WO2021237096A1

WO2021237096A1 - Durable implants and microparticles for long-term ocular therapy

Info

Publication number: WO2021237096A1
Application number: PCT/US2021/033662
Authority: WO
Inventors: Ming Yang; Yun Yu; Nu Hoang
Original assignee: Graybug Vision, Inc.
Priority date: 2020-05-21
Filing date: 2021-05-21
Publication date: 2021-11-25
Also published as: TW202207943A

Abstract

A biodegradable implant or microparticles of a timolol prodrug, optionally with timolol or a pharmaceutically acceptable salt thereof, typically for ocular therapy.

Description

DURABLE IMPLANTS AND MICROPARTICLES FOR LONG-TERM OCULAR THERAPY

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of provisional U.S. Application No. 63/028,417 filed May 21, 2020, which is incorporated by reference in its entirety.

FIELD OF THE INVENTION

This invention is in the area of implants and microparticles comprising a compound of Formula I, optionally with timolol or a pharmaceutically acceptable salt thereof, as described herein for medical, including ocular, therapy.

BACKGROUND

The structure of the eye can be divided into two segments referred to as the anterior and posterior. The anterior segment comprises the front third of the eye and includes the structures in front of the vitreous humor: the cornea, iris, ciliary body (including the pars plana), and lens. The posterior segment includes the back two-thirds of the eye and includes the sclera, choroid, retinal pigment epithelium, neural retina, optic nerve, and vitreous humor.

Important diseases affecting the anterior segment of the eye include glaucoma, allergic conjunctivitis, anterior uveitis, and cataracts. Diseases affecting the posterior segment of the eye include dry and wet age-related macular degeneration (AMD), cytomegalovirus (CMV) infection, choroidal neovascularization, acute macular neuroretinopathy, macular edema (such as cystoid macular edema and diabetic macular edema), Behcet’s disease, retinal disorders, diabetic retinopathy (including proliferative diabetic retinopathy), retinal arterial occlusive disease, central retinal vein occlusion, uveitis retinal disease, retinal detachment, ocular trauma, damage caused by ocular laser treatment or photodynamic therapy, photocoagulation, radiation retinopathy, epiretinal membrane disorders, branch retinal vein occlusion, anterior ischemic optic neuropathy, non-retinopathy diabetic retinal dysfunction and retinitis pigmentosa. Glaucoma is sometimes also considered a posterior ocular condition because a therapeutic goal of glaucoma treatment is to prevent or reduce the loss of vision due to damage or loss of retinal cells or optic nerve cells.

Typical routes of drug administration to the eye include topical, systemic, intravitreal, intraocular, intracameral, subconjunctival, sub-tenon, suprachoroidal, retrobulbar, and posterior juxtascleral. (Gaudana, R., et al., “Ocular Drug Delivery”, The American Association of Pharmaceutical Scientist Journal, 12(3)348-360, 2010).

A number of types of delivery systems have been developed to deliver therapeutic agents to the eye, including conventional (solution, suspension, emulsion, ointment, inserts, and gels), vesicular (liposomes, niosomes, discomes, and pharmacosomes), advanced materials (scleral plugs, gene delivery, siRNA, and stem cells), and controlled-release systems (implants, hydrogels, dendrimers, iontophoresis, collagen shields, polymeric solutions, therapeutic contact lenses, cyclodextrin carriers, microneedles, microemulsions, and particulates (microparticles and nanoparticles)).

Anterior drug delivery methods are common and are most often topical dosage forms, such as eye drops and ointments. While topical eyedrops are easy to administer, ocular bioavailability is often low because a topical dosage form needs to reside on the surface of the eye long enough to penetrate and enter multiple layers of the eye, including the tear film, cornea, conjunctiva, and the sclera. Blinking and wash out by tears and nasolacrimal drainage are two common barriers that prevent penetration into the eye. Furthermore, topical eye drops cannot reach the posterior of the eye. A common method of targeting the posterior of the eye includes injections and/or implants that target the vitreous or other surrounding tissue of the eye.

The first intravitreal implant, ganciclovir implant (Vitrasert, Bausch + Lomb), was approved by the FDA for the treatment of cytomegalovirus (CMV) retinitis in AIDS patients in 1996. The implant comprised a pellet of ganciclovir coated in a laminated system of biocompatible polymers. Ozurdex (Allergan) is an FDA-approved dexamethasone intravitreal implant for the treatment of macular edema secondary to RVO, noninfectious posterior uveitis, and DME. FDA- approved fluocinolone acetonide implants include Retisert (Bausch + Lomb) for the treatment of chronic noninfectious posterior uveitis and Iluvien (Alimera Sciences) for the treatment of DME in patients who are not steroid responders. In March 2020, the FDA approved the bimatoprost implant Durysta (Allergan) for the treatment of open-angle glaucoma or ocular hypertension.

Allergan has disclosed a biocompatible intraocular polymeric implant that can comprise a beta-adrenergic receptor antagonist, for example timolol maleate, in U.S. Patent No. 8,715,709 and PCT Application WO 2005/110380. Drug load of the disclosed implants varied from 10% to 50%, but at 50%, the implants exhibited very fast one day release and the optimal drug load for the implants was determined to be 26%. U.S. Patent Nos. 8,802,129; 8,911,768; and 9,233,071 also assigned to Allergan describe implants for the vitreous for the extended treatment of an ocular disorder after release of the active agent from the implant. Active agents that can be included in the implant include a VEGF inhibitor, a beta-adrenergic receptor antagonist, a prostamide, an alpha-2 adrenergic receptor agonist, and a retinoid.

Allegan has also disclosed ocular polymeric implants made by a double extrusion process wherein at least two polymers, such as PLGA ester and PLGA acid, are separately micronized and then blended together with an active agent, for example, dexamethasone, prior to extrusion into a filament in U.S. Patent Nos. 8,034,370; 8,034,366; 8,048,445; 8,506,897; 8,318,070; 8,778,381; 9,192,511; and 10,076,526. These implants are then cut into rods and administered for the treatment of ocular disorders.

Implants comprising a core of an antihypertensive agent, for example, a hypotensive lipid, a prostaglandin analogue, a beta-adrenergic receptor antagonist, or an alpha-adrenergic agonist, surrounded by a polymer are described in US Application US 2013/0017243 and US 2016/0256382 assigned to Allergan. Additional implants for ocular delivery are described in U.S. Patent No. 8,956,655 assigned to Allergan. The implants of the ‘655 patent are segmented and the segments provide individual and different drug release characteristics.

Allergan has disclosed a composite drug delivery material that can be injected into the eye of a patient that includes a plurality of microparticles dispersed in a media, wherein the microparticles contain a drug and a biodegradable or bioerodible coating and the media includes the drug dispersed in a depot-forming material, wherein the media composition may gel or solidify on injection into the eye (WO 2013/112434 Al, claiming priority to January 23, 2012). Allergan states that this invention can be used to provide a depot means to implant a solid sustained drug delivery system into the eye without an incision. In general, the depot on injection transforms to a material that has a viscosity that may be difficult or impossible to administer by injection.

In addition, Allergan has disclosed biodegradable microspheres between 40 and 200 pm in diameter, with a mean diameter between 60 and 150 pm that are effectively retained in the anterior chamber of the eye without producing hyperemia (US 2014/0294986). The microspheres contain a drug effective for an ocular condition with greater than seven-day release following administration to the anterior chamber of the eye. The administration of these large particles is intended to overcome the disadvantages of injecting 1-30 pm particles which are generally poorly tolerated. Dose Medical Corp has disclosed implants and medical devices for treating glaucoma, including a trabecular stunt and stenting device that in one embodiment allows aqueous humor to move between the anterior chamber and Schlemm’s canal in U.S. Patent Nos. 6,638,239; 7,135,009; 7,867,186; 7,708,711; 8,348,877; 9,066,782; and 9,789,001. Additional implants that allow for aqueous humor drainage from the anterior chamber to the uveoscleral outflow pathway are disclosed in U.S. Patent No. 9,636,255 and 10,206,813 and US 2017/0135857 assigned to Dose Medical Corp. Biodegradable ocular resorbable implants that comprise a hydrogel for delivery of a therapeutic agent are described in US 2019/0125581 assigned to Dose Medical Corp.

Glaukos Corporation has disclosed medical devices and methods for treating glaucoma with the goal of directing aqueous outflow from Schlemm’ s canal through the trabecular meshwork to restore normal intraocular pressure in U.S. Patent Nos. 7,094,225; 7,273,475; and 8,337,445. Glaukos Corporation has also disclosed anterior chamber ocular implants in U.S. Patent No. 10,245,178 and US 2019-0224046.

Oxular Limited has disclosed ophthalmic compositions for delivery to the suprachoroidal space comprising a solid or a semi-solid elongate body that undergoes biodegradation in the suprachoroidal space after injection (WO 2016/042163) and compositions that remain localized after administration comprising biodegradable polymer particles, biodegradable excipient, and bulking agents (WO2019/053466).

Incept, LLC has disclosed a drug implant that changes shape in vivo when the active agent is released in PCT Application WO 2017/091749.

Johns Hopkins University has filed a number of patents claiming formulations for ocular injections including WO2013/138343 titled “Controlled Release Formulations for the Delivery of HIF-1 Inhibitors”, WO2013/138346 titled “Non-linear Multiblock Copolymer-drug Conjugates for the Delivery of Active Agents”, WO2011/106702 titled “Sustained Delivery of Therapeutic Agents to an Eye Compartment”, WO2016/025215 titled “Glucorticoid-loaded Nanoparticles for Prevention of Corneal Allograft Rejection and Neovascularization”, W02016/100392 titled “Sunitinib Formulations and Methods for Use Thereof in Treatment of Ocular Disorders”, W02016/100380 titled “Sunitinib Formulation and Methods for Use Thereof in Treatment of Glaucoma” and WO2016/118506 titled “Compositions for the Sustained Release of Anti- Glaucoma Agents to Control Intraocular Pressure”. GrayBug Vision, Inc. discloses prodrugs for the treatment of ocular therapy in granted U. S. Patent Nos. 9,808,531; 9,956,302; 10,098,965; 10,117,950; 10,111,964; 10,159,747; and 10,458,876; U.S. Applications US 2020/0031783; US 2020-0308162; and US 2021-0040111; and, and PCT Application WO 2020/069353. Aggregating microparticles for ocular therapy are described in U.S. Patent No. 10,441,548, U.S. Application No. US 2018-0326078, and PCT Application WO 2020/102758. U.S. Application US 2021/085607 describes aggregating microparticles and processes for making aggregating microparticles.

To treat ocular diseases, and in particular diseases of the posterior segment, the drug must be delivered in therapeutic levels and for a sufficient duration to achieve efficacy. This seemingly straightforward goal is difficult to achieve in practice.

The object of this invention is to provide improved compositions and methods for durable, long-term, controlled drug delivery of an active agent for the treatment of a range of medical disorders, including ocular disorders.

SUMMARY

The present invention provides new controlled release implant and implant formulations with advantageous properties comprising a compound of Formula I, which is a prodrug of the b- adrenergic antagonist timolol, for the treatment of a medical disorder, including an ocular disease that is responsive to timolol, as described herein. Systemically, timolol is used, for example, to reduce blood pressure to treat a range of indications. Timolol is also known to reduce intraocular pressure and ocular hypertension via topical eyedrops. Although eye drops are easy to administer, ocular bioavailability with eye drops is typically low because blinking, tear wash out, and nasolacrimal drainage often prevent the solution from residing on the eye long enough to penetrate through the required layers of the eye, including the initial tear film. Further, topical eye drops are unable to reach the posterior of the eye.

In some embodiments, the microparticle and implant formulations of the present invention comprise both a compound of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate.

Due to the high solubility of timolol maleate in aqueous medium, it is difficult to formulate an implant or microparticle comprising timolol or a pharmaceutically acceptable salt thereof that does not exhibit high burst release within hours or even one day. Once the implant contacts the aqueous medium, due to the high solubility of timolol, any timolol on the surface or close to the surface may quickly diffuse from the formulation, resulting in an initial high burst release. This is especially common with high drug loaded formulations, which limits the loading of timolol in an implant or microparticle.

As disclosed herein, it has been surprisingly discovered that the incorporation of timolol maleate with a timolol prodrug of Formula I in an ocular formulation results in linear, sustained release of the timolol prodrug and timolol maleate for about at least three months or more. As discussed in Example 8 and a non-limiting exemplary illustration of the present invention, implants that incorporate both timolol maleate and a prodrug compound of Formula I with a combined drug loading as high as 70% by weight exhibit linear, sustained release that lasts for 6 months. As shown in FIG. 17 and discussed in Example 8, an implant incorporating 40% timolol maleate alone exhibited high burst release with 80% cumulative release at timepoint 0. It has been unexpectedly discovered that the formulations of the present invention do not exhibit burst release.

Therefore, in one embodiment of the present invention, a durable controlled release formulation comprising both Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example, timolol maleate, in a biodegradable microparticle or implant is provided that is suitable for long-term ocular therapy. In certain embodiments, the combined drug load of Formula I and timolol of a pharmaceutically acceptable salt thereof is about 40% or greater, for example about 45% or greater, about 50% or greater, about 60% or greater, about 75% or greater, about 90% or greater or even as high as about 100% by weight. In certain embodiments, the implant provides sustained linear release of the compound of Formula I and timolol for at least about one month, at least about two months, at least about three months, at least about four months, at least about five months, or at least about six months or more.

The present invention also provides implants that comprise only a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof with drug loads of greater than 45%, 60%, 90%, or even 100% by weight. As discussed herein, it is difficult to formulate timolol maleate at high drug loads without high burst release. The implants of the present invention are advantageous because even at high drug loads, the implants have linear sustained of the timolol prodrug. Formulations with high drug loads are advantageous because the dosing can be minimized, which improves patient comfort and compliance. As discussed in Example 6 and as a non-limiting exemplary illustration, implants with drug loads as high as 90% by weight exhibit sustained release for 6 months (FIG. 14). These improved and advantageous drug release kinetics could not have been predicted in advance. Therefore, the present invention provides implants comprising a compound of Formula I that provide sustained linear release of the compound of Formula I for at least about one month, at least about two months, at least about three months, at least about four months, at least about five months, or at least about six months or more.

The implant can be any desired shape, and is typically a rod or cylinder, including a cylindrical pellet. The rod is typically, for example, in the range of at least about 150 to about 1000 micrometers or less (pm, microns) in diameter and at least about 1 to about 10 millimeters (mm) or less in length, and more typically, for example, in the range of at least about 300- to 500-micron diameter and at least about 3 to about 7.5 mm or less in length or at least about 3 to about 8 mm or less in length. In a preferred embodiment, the rod is between at least about 300 to 600 microns or less in diameter and between about at least 1 and 10 or less mm in length.

A cylindrical pellet is typically, for example, in the range of at least about 400 to about 1000 microns or less in width, and often no more than about 10 mm in length, and in the range, for example, of at least about 400 to about 1000 microns or less in height, and more typically in the range, for example, of at least about 800 to about 1000 microns or less in width, for example at least about 800 to about 1000 or less microns in height, and for example about not more than about 7 mm in length. In one embodiment, the cylindrical pellet is at least about 150 to about 1200 microns or less in width, at least about 1 mm to about 10 mm or less in length, and at least about 150 to about 1200 or less microns in height. In another embodiment, the cylindrical pellet is at least about 400 to about 1000 or less microns in width, at least about 3 mm to about 10 mm or less in length, and at least about 400 to about 1000 or less microns in height.

In certain embodiments, the implant has a length of between at least about 3 to about 10 or less mm and for every 6 mm of implant, the average dose of the timolol prodrug of Formula 1 ranges from at least about 0.10 mg to at least about 1.10 mg. In certain embodiments, the average dose of the timolol prodrug of Formula I for every 6 mm of implant is at least about 0.10 mg, 0.20 mg, 0.30 mg, 0.40 mg. 0.50 mg, 0.60 mg, 0.70 mg, 0.80 mg, 0.90 mg, 1.0 mg, or 1.10 mg.

In certain embodiments, the implant comprises both timolol or a pharmaceutically acceptable salt thereof and a timolol prodrug of Formula I and has a length of between at least about 3 to about 10 mm or less and for every 6 mm of implant, the average dose of the timolol prodrug of Formula 1 ranges from at least about 0.50 mg to at least about 1.10 mg and the average dose of timolol ranges from about 0.05 mg to about 0.40 mg. In certain embodiments, the average dose of the timolol prodrug of Formula I for every 6 mm of implant is at least about 0.50 mg, 0.60 mg, 0.70 mg, 0.80 mg, 0.90 mg, 1.0 mg, or 1.10 mg and the average dose of timolol for every 6 mm of implant is at least about 0.05 mg, 0.10 mg, 0.20 mg, 0.30 mg, or 0.40 mg.

In certain embodiments, the durable ocular implant comprising a timolol prodrug of Formula I is provided and the implant is constructed of at least about 80, 85, 90, 95 or even about 100% by weight of the compound of Formula I. In another aspect, the implant is a blend of a high load of Formula I in a biodegradable polymeric material. In one embodiment, the implant is a blend of a high load of Formula I in a biodegradable polymeric material and an excipient, such as a sugar or a plasticizer. In one embodiment, the plasticizer is polyethylene glycol. In another embodiment, the implant comprises a compound of Formula I and an excipient and does not have a polymeric material.

In certain embodiments, a durable ocular implant comprising both a timolol prodrug of Formula I and timolol or a pharmaceutically acceptable salt, for example, timolol maleate, is provided. In certain embodiments, the implant comprises at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, or even at least about 99% or 100% by weight of the compound of Formula I and timolol or a pharmaceutically acceptable salt combined. In one embodiment, the implant further comprises an excipient, such as a sugar. In one embodiment, timolol or a pharmaceutically acceptable salt thereof is timolol maleate.

The implant can be administered via needle or device into any area of the eye that requires therapy or which can serve as a depot location for drug release, including but not limited to the vitreous, suprachoroidal, subchoroidal, subconjunctival, scleral, episcleral, intracameral or other convenient location, or as selected by the health care practitioner. These polymeric implants allow for drug delivery directly at the target site and are administered via a procedure that is minimally invasive. In certain embodiments, the implant delivers timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof for one month, two months, three months, fourth months, five months, six months or more, limiting the amount of required injections.

In certain embodiments, the polymeric implant of the present invention is in the shape of a rod, a cylindrical pellet, a disc, a wafer, a sheet, or a plug. The implant of the present invention can be, for example, fabricated by a variety of techniques, including compression, solvent casting, hot melt extrusion, injection molding, and 3D printing.

In certain embodiments, a powder of a timolol prodrug of Formula I is used to formulate the implant via, for example, compression, solvent casting, or hot melt extrusion.

In alternative embodiments, microparticles comprising a timolol prodrug of Formula I are used as the starting material to formulate the implants via, for example, compression, solvent casting, or hot melt extrusion. In this embodiments, pre-mixing in not required because the components are already well-mixed during the microparticle formulation. The drug load of the microparticles used as a starting material can be any amount that fulfills the intended purpose, including but not limited to up to at least about 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or even 100% by weight. Example 10 is a non-limiting illustrative example of the process to form an implant from microparticles. In certain embodiments, the microparticles are surface-treated as described herein. In certain embodiments, the microparticles are not surface-treated as described herein.

As described in non-limiting Example 11, implants of the present invention can also be formulated from (a) microparticles comprising a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and (b) un encapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof. In one embodiment, the unencapsulated prodrug of Formula I is used in micronized form. In certain embodiments, these implants are formed via compression, solvent casting, or hot melt extrusion. In certain embodiments, the implant comprises up to at least about 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or even 100% by weight of unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof.

In other certain embodiments, the implant is formulated from a powder that comprises both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate. In alternative embodiments, the implant is formulated from microparticles that comprise both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate. In certain embodiments, the microparticles are surface- treated as described herein. In certain embodiments, the microparticles are not surface-treated as described herein. In a further alternative embodiment, the implant is formulated from (a) microparticles that comprise a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and/or timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate and (b) unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof. In one embodiment, the unencapsulated prodrug of Formula I is micronized. Alternatively, the implant is formulated from (a) microparticles that comprise both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate and (b) unencapsulated micronized timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate.

The present invention also includes implants formulated from (a) microparticles that comprise both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and/or timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate and (b) unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and micronized timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate. In one embodiment, the unencapsulated prodrug of Formula I is micronized.

The present invention further includes implants formulated from (a) microparticles that comprise both timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate and/or a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and (b) unencapsulated micronized timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate.

In certain embodiments, the implant is inserted via a needle, including but not limited to a 21, 22, 23, 24, 25, 26 or 27 gauge needle, which may optionally have a thin or ultra-thin needle wall. In one embodiment, the implant is inserted intravitreally. In an alternative embodiment, the implant is inserted into the subconjunctival or suprachoroidal space. In certain embodiments, the needle is attached to an applicator, a device, or an inserter for minimally invasive injections. In another embodiment, the implant is delivered using a non-needle based medical device. In an alternative embodiment, the implant is surgically inserted.

In certain embodiments, the biodegradable implant is polymeric, and the polymer comprises no more than about 10, no more than about 20, no more than about 30, no more than about 40, no more than about 50, or no more than about 60 weight percent of the implant with the balance of the weight being a compound of Formula I or a pharmaceutically acceptable salt thereof and other non-active agents dispersed in the biocompatible biodegradable polymer. Example 5 provides a non-limiting illustrative embodiment of a compound of Formula I formulated into a polymeric implant for ocular delivery.

In alternative embodiments, the biodegradable implant is polymeric and the polymer comprises no more than about 10, no more than about 20, no more than about 30, no more than about 40, no more than about 50, or no more than about 60 weight percent of the implant with the balance of the weight being a compound of Formula I or a pharmaceutically acceptable salt thereof, timolol or a pharmaceutically acceptable salt thereof, and other non-active agents dispersed in the biocompatible biodegradable polymer. Example 7 provides illustrative non-limiting embodiments of polymeric implants comprising both a prodrug of Formula I and timolol maleate.

In certain embodiments, the non-active ingredient is an additive, such as a plasticizer, which helps to improve the flexibility and processability of the implant. Non-limiting examples of plasticizers as non-active ingredients include benzyl alcohol, benzyl benzoate, ethyl heptanoate, propylene carbonate, triacetin, and triethyl citrate.

Non-limiting examples of polymers included in the implants and polymeric microparticles of the present invention include, but are not limited to: poly(lactide co-glycolide); poly(lactic acid); poly(lactide-co-glycolide) covalently linked to polyethylene glycol; more than one biodegradable polymer or copolymer mixed together, for example, a mixture of poly(lactide-co-glycolide) and poly(lactide-co-glycolide) covalently linked to polyethylene glycol, a mixture of poly(lactic acid) and poly(lactide-co-glycolide) covalently linked to polyethylene glycol, or a mixture of poly(lactic acid), poly(lactide-co-glycolide) and poly(lactide-co-glycolide) covalently linked to polyethylene glycol; and, poly(lactic acid).

In certain embodiments, the controlled-release formulation comprises a biodegradable polymer such as PLGA, PLA, PLGA-PEG, PLA-PEG or a combination thereof. In some embodiments, the formulation comprises PLGA and PLGA-PEG, or PLGA, PLA and PLGA-PEG. In some embodiments, the formulation comprises PLA and PLGA-PEG or PLA-PEG.

In certain aspects, the biodegradable implant (or insert) does not include a polymer, but instead the implant is made from the compound of Formula I or a pharmaceutically acceptable salt thereof with the balance of the weight being a non-active agent or excipient, or a second biologically active compound. In one aspect, the implant is non-polymeric and the compound of Formula I or a pharmaceutically acceptable salt thereof comprises about 100 weight percent of the implant.

Alternatively, the non-polymeric biodegradable implant (or insert) is made from timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I or a pharmaceutically acceptable salt thereof with the balance of the weight being a non-active agent or excipient. In this embodiment, the implant is non-polymeric and timolol or a pharmaceutically acceptable salt thereof and the compound of Formula I or a pharmaceutically acceptable salt thereof comprise about 100 weight percent of the implant.

In certain embodiments the polymeric or non-polymeric implant exhibits a hardness rating of at least about 5 gram -force needed to compress the implant at 30% of strain. In certain embodiments, the implant exhibits a hardness rating of at least about 10 gram -force, 15 gram- force, 20 gram-force, 40 gram-force, 50 gram-force, 70 gram-force, 100 gram-force, 120 gram- force, 150 gram-force, 170 gram -force, or more when measured in vitro. The hardness of the aggregated microparticle depot can be confirmed in vitro in vitreous fluid, in phosphate buffered saline, or in water or other physiologically acceptable aqueous solution, including an aqueous solution that includes one or more components of the vitreous, which are well-known. The vitreous humor fluid in vivo typically contains 98-99% water, salts, sugars, vitrosin, fibrils with glycosaminoglycan, hyaluronan (i.e., hyaluronic acid), opticin, and various proteins. The vitreous humor typically has a viscosity of approximately 2-4 times that of water. In one embodiment, the hardness is tested in a hyaluronic acid-based solution with a viscosity that in one embodiment approximately mimics that of the vitreous. In certain embodiments, the hardness is measured in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

In certain embodiments, the implant is polymeric, and the polymer comprises no more than about 30, 40, or 50 weight percent of the implant with the balance of the weight being a compound of Formula I or a pharmaceutically acceptable salt thereof or other non-active agents and the implant exhibits a hardness rating of at least about 5 gram-force needed to compress the implant at 30% of strain.

In one embodiment, the implant is non-polymeric and the compound of Formula I or a pharmaceutically acceptable salt thereof comprises about 100 weight percent of the implant and the implant exhibits a hardness rating of at least about 5 gram-force needed to compress the implant at 30% of strain.

In an alternative embodiment, the implant is polymeric, and the polymer comprises no more than about 30, 40, or 50 weight percent of the implant with the balance of the weight being timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I or a pharmaceutically acceptable salt thereof or other non-active agents and the implant exhibits a hardness rating of at least about 5 gram-force needed to compress the implant at 30% of strain.

In an alternative embodiment, the implant is non-polymeric and timolol or a pharmaceutically acceptable salt thereof and the compound of Formula I or a pharmaceutically acceptable salt thereof comprise about 100 weight percent of the implant and the implant exhibits a hardness rating of at least about 5 gram -force needed to compress the implant at 30% of strain.

In an alternative aspect of the present invention, the controlled release formulation is a microparticle, optionally with a diameter from about 25 pm to about 45 pm. In one embodiment, the microparticle is treated as described herein to form an aggregated microparticle (which may be a pellet or a depot), in vivo of at least about 500 microns.

In certain embodiments, a durable controlled release formulation of Formula I in a biodegradable microparticle is provided that is suitable for long-term ocular therapy and is prepared with a Formula I load of about 42% or greater, for example about 45% or greater, about 50% or greater, about 60% or greater, about 75% or greater, about 90% or greater or even as high as about 100%.

In some embodiments, the microparticles of the present invention have been mildly surface-treated, for example with a surface-treatment agent comprising an aqueous base in an organic solvent, such as NaOH in EtOH, and aggregate in vivo to an aggregated microparticle depot of at least 500 pm. In certain embodiments, the concentration of the NaOH solution is between about 2.0 mM and about 12 mM. In certain embodiments, the concentration of the NaOH solution is between about 2 mM and about 4 mM, between about 4 mM and 10 mM or between about 6 mM and 8 mM. In certain embodiments, the percentage of EtOH in the NaOH/EtOH solution is at least about 10%, about 30%, about 40%, about 45%, about 50%, about 55%, or about 70%.

In some embodiments, the aggregated microparticle depot exhibits a hardness rating of at least about 10, 15, 20, 40, 50, 60, 70, 80, 90, 100, or more gram-force needed to compress the depot at 30% of strain when measured in vitro. In certain embodiments, the hardness is measured in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

It is advantageous to provide an aggregated microparticle depot with increased hardness and durability because the viscosity of vitreous fluid decreases with age while ocular diseases and problems become more prevalent. It is also advantageous to provide a microparticle with high drug load to limit the amount of non-therapeutic polymeric carrier delivered with the active agent. In certain embodiments, the microparticles of the present invention with high drug loads and minimal polymeric content are able to provide sustained drug release over an extensive time period, for example one month, two months, three months, four months, five months, six months or more. This long-term drug release requires fewer invasive procedures to administer the drug.

As discussed in Example 2, in one non-limiting example, microparticles with a drug load of 45% by weight of Formula I mildly treated with 55% EtOH and 5 mM NaOH aggregated to a depot in vitro and exhibited a hardness score (the gram force required to compress the depot at 30% of strain) of 76.0 g of force when suspended in sodium hyaluronate solution at a concentration of 200 mg/mL and a hardness score of 582 g of force when suspended at a concentration of 400 mg/mL (Lot N, Table 2). Further, microparticles with a drug load of 60% by weight (Example 3) and 100% (Example 4) that had been surface-treated with EtOH and NaOH aggregated in vitro and were resistant to disintegration in an oscillation assay to determine the integrity of the depot.

In certain embodiments, the aggregating biodegradable microparticles with high loading of one or more active agents described herein, for example loadings of 42% or greater, for example greater than about 45%, 50%, 60%, 75%, 90% or even as high as about 100% by weight, aggregate in vivo to an aggregated microparticle depot with improved hardness and durability for long-term ocular therapy. In one embodiment, the aggregating microparticles have a drug load of at least about 60% by weight. In one embodiment, the aggregating microparticles have a drug load of about 100% by weight. In certain embodiments, the microparticles of the present invention with drug loads ranging from about 42%-100% by weight form an aggregated microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10 gram-force, and in some embodiments, at least about 20, 40, 50, 70, and even 100 or greater gram-force needed to compress the depot at 30% of strain. In certain embodiments, the hardness is measured in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

In an alternative embodiment, the aggregating biodegradable microparticles of the present invention comprise both a compound of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example, timolol maleate. In certain embodiments, the drug load of both the compound of Formula I and timolol or a pharmaceutically acceptable salt together is between about 1% and 10% by weight, between about 10% and 20% by weight, between about 20% and 30% by weight, between about 30% and 40% by weight, between about 40% and 50% by weight, between about 50% and 60% by weight, between about 60% and 70% by weight, between about 70% and 80% by weight, between about 80% and 90% by weight, or even greater than 90% by weight.

The present invention further includes a suspension of aggregating biodegradable microparticles with high loading of one or more active agents described herein, for example loadings of 42% by weight or greater, for example greater than about 45%, 50%, 60%, 75%, 90% or even as high as about 100% by weight in a diluent for injection that comprises an additive that softens the surface polymer of the microparticle and improves aggregation prior to injection. In one embodiment, the additive is a plasticizer, for example benzyl alcohol or triethyl citrate.

In a principal embodiment, the microparticles, which may be treated for in vivo aggregation, or the implant, of the present invention comprise an effective amount of a compound of Formula I or a pharmaceutically acceptable salt thereof to a host to treat an ocular or other disorder that can benefit from local delivery. Nonlimiting examples of such diseases include dry and wet age-related macular degeneration (AMD), cytomegalovirus (CMV) infection, choroidal neovascularization, acute macular neuroretinopathy, macular edema (such as cystoid macular edema and diabetic macular edema), diabetic retinopathy (including proliferative diabetic retinopathy) and glaucoma.

The timolol prodrug in the implant or microparticle of the present invention is a compound of Formula I:

or a pharmaceutically acceptable salt thereof; wherein:

R¹ and R² are independently selected from (i) hydrogen and -C(0)R³;

wherein R¹ and R² cannot both be hydrogen;

R³ is independently selected from H, alkyl, cycloalkyl, cycloalkylalkyl, heterocycle, heterocycloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, aryloxy, and alkyloxy; R⁴ is independently selected from hydrogen, -C(0)R³, aryl, alkyl, cycloalkyl, cycloalkylalkyl, heterocyclyl, heterocycloalkyl, arylalkyl, heteroaryl, and heteroarylalkyl; x and y are integers independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20; z is an integer independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

In certain embodiments, the compound of Formula I is a compound selected from:

or a pharmaceutically acceptable salt thereof. In an embodiment, the compound of Formula I is:

or a pharmaceutically acceptable salt thereof.

In an embodiment, the compound of Formula I is:

or a pharmaceutically acceptable salt thereof.

The present invention describes implants comprising a prodrug of Formula I or a pharmaceutically acceptable salt thereof and includes at least the following embodiments: (a) a biodegradable implant comprising a compound of Formula I or a pharmaceutically acceptable salt thereof;

(b) a biodegradable implant comprising both timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I or a pharmaceutically acceptable salt thereof;

(c) a biodegradable implant formed from microparticles comprising a compound of Formula I or a pharmaceutically acceptable salt thereof;

(d) a biodegradable implant formed from microparticles comprising both timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I or a pharmaceutically acceptable salt thereof; (e) a biodegradable implant formed from (a) microparticles that comprise a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and/or timolol or a pharmaceutically acceptable salt thereof and (b) unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof;

(f) a biodegradable implant formed from (a) microparticles that comprise both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof and (b) unencapsulated micronized timolol or a pharmaceutically acceptable salt thereof;

(g) a biodegradable implant formed from (a) microparticles that comprise both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof and (b) unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and micronized timolol or a pharmaceutically acceptable salt thereof;

(h) the implant of (a)-(g) wherein timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof is encapsulated or dispersed in at least one biodegradable polymer;

(i) the implant of (h) wherein the implant comprises PLGA;

(j) the implant of (h) or (i) wherein the implant comprises PLA;

(k) the implant of (h)-(j) wherein the implant further comprises PLGA conjugated to PEG;

(l) the implant of (h)-(k) wherein the implant further comprises PLA conjugated to PEG;

(m) the implant of (h)-(l) wherein the implant further comprises PEG;

(n) the implant of (a)-(m) wherein the implant further comprises a non-active excipient;

(o) the implant of (n) wherein the excipient is a plasticizer;

(p) the implant of (o) wherein the plasticizer is benzyl alcohol;

(q) the implant of (o) wherein the plasticizer is tri ethyl citrate;

(r) the implant of (a)-(q) wherein the implant releases the compound of Formula I over a sustained period of at least one month;

(s) the implant of (a)-(q) wherein the implant releases the compound of Formula I over a sustained period of at least two months;

(t) the implant of (a)-(q) wherein the implant releases the compound of Formula I over a sustained period of at least three months; (u) the implant of (a)-(q) wherein the implant releases the compound of Formula I over a sustained period of at least four months;

(v) the implant of (a)-(q) wherein the implant releases the compound of Formula I over a sustained period of at least five months;

(w) the implant of (a)-(q) wherein the implant releases the compound of Formula I over a sustained period of at least six months or more;

(x) the implant of (b) and (d)-(q) wherein the implant releases timolol and the compound of Formula I over a sustained period of at least one month;

(y) the implant of (b) and (d)-(q) wherein the implant releases timolol and the compound of Formula I over a sustained period of at least two months;

(z) the implant of (b) and (d)-(q) wherein the implant releases timolol and the compound of Formula I over a sustained period of at least three months;

(aa) the implant of (b) and (d)-(q) wherein the implant releases timolol and the compound of Formula I over a sustained period of at least four months;

(bb) the implant of (b) and (d)-(q) wherein the implant releases timolol and the compound of Formula I over a sustained period of at least five months;

(cc) the implant of (b) and (d)-(q) wherein the implant releases timolol and the compound of Formula I over a sustained period of at least six months or more;

(dd) the implant of (a)-(cc) wherein timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof comprises between about 15 - 40 weight percent of the implant;

(ee) the implant of (a)-(cc) wherein timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof comprises between about 40 - 65 weight percent of the implant;

(ff) the implant of (a)-(cc) wherein timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof comprises between about 65 - 99 weight percent of the implant;

(gg) the implant of (a) and (c)-(w) wherein timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof comprises 100% weight percent of the implant; (hh) the implant of (b), (d)-(q), and (x)-(ff) wherein timolol or a pharmaceutically acceptable salt thereof is timolol maleate;

(ii) the implant of (a)-(hh) wherein the implant exhibits a hardness rating of at least 5-gram force needed to compress the particle at 30% strain in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water;

(jj) the implant of (ii) wherein the implant exhibits a hardness rating of at least 10-gram force need to compress the particle at 30% strain;

(kk) the implant of (ii) wherein the implant exhibits a hardness rating of at least 15-gram force need to compress the particle at 30% strain;

(11) the implant of (ii) wherein the implant exhibits a hardness rating of at least 30-gram force need to compress the particle at 30% strain;

(mm) the implant of (ii) wherein the implant exhibits a hardness rating of at least 40-gram force need to compress the particle at 30% strain;

(nn) the implant of (a)-(mm) in the shape of a rod;

(oo) the implant of (a)-(mm) in the shape of a cylindrical pellet;

(pp) the implant of (a)-(mm) in the shape of a sphere;

(qq) the implant of (a)-(oo) wherein the length of implant is between about 3 and 10 mm; (rr) the implant of (qq) wherein the diameter of the implant is between about 0.3 and 0.6 mm;

(ss) the implant of (a)-(rr) wherein R¹ and R² in the compound of Formula I are independently selected from:

(tt) the implant of (a)-(rr) wherein R¹ and R² in the compound of Formula I are independently selected from:

(uu) the implant of (a)-(rr) wherein R¹ and R² in the compound of Formula I are independently selected from:

5

or a pharmaceutically acceptable salt thereof;

(ww) the implant of (a)-(rr) wherein the compound of Formula I is selected from

or a pharmaceutically acceptable salt thereof;

(xx) the implant of (a)-(rr) wherein the compound of Formula I is

or a pharmaceutically acceptable salt thereof;

(yy) the implant of (a)-(rr) wherein the compound of Formula I is

or a pharmaceutically acceptable salt thereof;

(zz) the implant of (a)-(rr) wherein the compound of Formula I is

or a pharmaceutically acceptable salt thereof;

(aaa) a method to treat a medical disorder selected from glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves. In another embodiment more generally, the disorder treated is allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy comprising administering the implant of embodiments (a)-

(zz);

(bbb) the method of (aaa) wherein the implant is administered intravitreally;

(ccc) the method of (aaa) wherein the implant is administered to the suprachoroidal space; (ddd) the method of (aaa) wherein the implant is administered to the subconjunctival space; (eee) the method of (aaa) wherein the disorder is glaucoma;

(fff) the method of (eee) wherein the glaucoma is primary open angle glaucoma; and (ggg) embodiments (aaa)-(fff) wherein the host is a human.

The present invention also describes microparticles comprising a prodrug of Formula I or a pharmaceutically acceptable salt and includes at least the following embodiments:

(a) solid microparticles comprising a compound of Formula I or a pharmaceutically acceptable salt thereof and surfactant wherein the microparticles are sufficiently small to be injected in vivo ;

(b) solid microparticles comprising timolol or a pharmaceutically acceptable salt thereof, a compound of Formula I or a pharmaceutically acceptable salt thereof, and surfactant wherein the microparticles are sufficiently small to be injected in vivo ;

(c) the solid microparticles of (a) wherein the microparticles are surface-modified biodegradable solid aggregating microparticles and wherein

(i) the drug loading of the compound of Formula I or pharmaceutically acceptable salt is about at least 42% by weight or greater;

(ii) the microparticles have a modified surface which has been treated under mild conditions to partially remove surfactant;

(iii) are sufficiently small to be injected in vivo ; and (iv) aggregate in vivo to form at least one aggregated microparticle depot of at least 500 pm in vivo in a manner that provides sustained drug delivery in vivo for at least one month;

(d) the solid microparticles of (b) wherein the microparticles are surface-modified biodegradable solid aggregating microparticles and wherein

(i) the microparticles have a modified surface which has been treated under mild conditions to partially remove surfactant;

(ii) are sufficiently small to be injected in vivo ; and

(iii) aggregate in vivo to form at least one aggregated microparticle depot of at least 500 pm in vivo in a manner that provides sustained drug delivery in vivo for at least one month;

(e) embodiment (c) or (d) wherein the drug loading is 60% by weight or greater;

(f) embodiment (c) or (d) wherein the drug loading is 70% by weight or greater;

(g) embodiment (c) or (d) wherein the drug loading is 85% by weight or greater;

(h) embodiment (c) or (d) wherein the drug loading is 90% by weight or greater;

(i) embodiment (c) or (d) wherein the drug loading is about 100% by weight;

(j) embodiments (a)-(i) wherein timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof is encapsulated or dispersed in at least one hydrophobic polymer and at least one hydrophobic polymer conjugated to a hydrophilic polymer;

(k) embodiment (j) wherein the at least one hydrophobic polymer is PLGA;

(l) embodiment (j) wherein the at least one hydrophobic polymer is PLA;

(m) embodiments (j)-(l) wherein at least one hydrophobic polymer conjugated to a hydrophilic polymer is PLGA conjugated to PEG;

(n) embodiments (j)-(l) wherein at least one hydrophobic polymer conjugated to a hydrophilic polymer is PLA conjugated to PEG;

(o) embodiments (a)-(i) wherein timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof is encapsulated or dispersed in PLGA and PLGA conjugated to PEG; (p) embodiments (a)-(i) wherein timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof is encapsulated or dispersed in PLGA, PL A, and PLGA conjugated to PEG;

(q) the surface-modified biodegradable solid aggregating microparticles of embodiments (c)-(p) wherein the surface-modified biodegradable solid aggregating microparticles are surface treated with a base and an organic solvent;

(r) embodiment (q) wherein the base is sodium hydroxide, potassium hydroxide, or lithium hydroxide;

(s) embodiment (r) wherein the base is sodium hydroxide; (t) embodiment (q)-(s) wherein the organic solvent in an alcohol;

(u) embodiment (t) wherein the alcohol is methanol;

(v) embodiments (a)-(u) wherein the timolol or a pharmaceutically acceptable thereof is timolol maleate;

(w) any of the above embodiments wherein R¹ and R² in the compound of Formula I are independently selected from:

(x) any of the above embodiments wherein R¹ and R² in the compound of Formula I are independently selected from:

(y) any of the above embodiments wherein R¹ and R² in the compound of Formula I are independently selected from:

5

or a pharmaceutically acceptable salt thereof;

or a pharmaceutically acceptable salt thereof;

(bb) any of the above embodiments wherein the compound of Formula I is

or a pharmaceutically acceptable salt thereof; (cc) any of the above embodiments wherein the compound of Formula I is

or a pharmaceutically acceptable salt thereof;

(dd) any of the above embodiments wherein the compound of Formula I is

or a pharmaceutically acceptable salt thereof;

(ee) a suspension of microparticles as described in embodiments (a)-(dd) in a diluent for injection that includes an additive that softens the surface of the microparticle before administration to prepare the microparticles for aggregation; (ff) embodiment (ee) wherein the additive is a plasticizer;

(gg) embodiment (ff) wherein the plasticizer is benzyl alcohol;

(hh) embodiment (ff) wherein the plasticizer is tri ethyl citrate;

(ii) embodiments (ee)-(hh) wherein the aggregated microparticle depot exhibits a hardness rating of at least 10 gram -force needed to compress the depot at 30% strain in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water;

(jj) embodiment (ii) wherein the hardness rating is at least 20 gram-force;

(kk) embodiment (ii) wherein the hardness rating is at least 40 gram-force;

(11) embodiment (ii) wherein the hardness rating is at least 50 gram-force;

(mm) embodiment (ii) wherein the hardness rating is at least 70 gram-force;

(nn) embodiment (ii) wherein the hardness rating is at least 100 gram-force;

(oo) a method to treat a medical disorder selected from (i) glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves; (ii) allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy or (iii) cytomegalovirus (CMV) infection, choroidal neovascularization, acute macular neuroretinopathy, macular edema (such as cystoid macular edema and diabetic macular edema), Behcet’s disease, retinal disorders, diabetic retinopathy (including proliferative diabetic retinopathy), retinal arterial occlusive disease, central retinal vein occlusion, uveitis retinal disease, retinal detachment, ocular trauma, damage caused by ocular laser treatment or photodynamic therapy, photocoagulation, radiation retinopathy, epiretinal membrane disorders, branch retinal vein occlusion, anterior ischemic optic neuropathy, non-retinopathy diabetic retinal dysfunction or retinitis pigmentosa; comprising administering the biodegradable solid microparticles of embodiments (a)-(dd) and (ee)-(nn) or the suspension of embodiments (w)-(z) in a host in need thereof;

(pp) the method of (oo) wherein the microparticles are administered intravitreally;

(qq) the method of (oo) wherein the microparticles are administered to the suprachoroidal space;

(rr) the method of (oo) wherein the microparticles are administered to the subconjunctival space; (ss) the method of (oo) wherein the disorder is glaucoma;

(tt) the method of (ss) wherein the glaucoma is primary open angle glaucoma; and

(uu) embodiments (oo)-(tt) wherein the host is a human.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A are an aggregated microparticles from Lot A suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot A are in Table 1.

FIG. IB are an aggregated microparticles from Lot A suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot A are in Table 1.

FIG. 1C are an aggregated microparticles from Lot A suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot A are in Table 1.

FIG. ID are an aggregated microparticles from Lot A suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot A are in Table 1.

FIG. IE are an aggregated microparticles from Lot B suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot B are in Table 1.

FIG. IF are an aggregated microparticles from Lot B suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot B are in Table 1.

FIG. 1G are an aggregated microparticles from Lot B suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot B are in Table 1.

FIG. 1H are an aggregated microparticles from Lot B suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot B are in Table 1.

FIG. II are an aggregated microparticles from Lot C suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot C are in Table 1.

FIG. 1J are an aggregated microparticles from Lot C suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot C are in Table 1.

FIG. IK are an aggregated microparticles from Lot C suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot C are in Table 1.

FIG. 1L are an aggregated microparticles from Lot C suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot C are in Table 1.

FIG. 1M are an aggregated microparticles from Lot D suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot D are in Table 1.

FIG. IN are an aggregated microparticles from Lot D suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot D are in Table 1. FIG. 10 are an aggregated microparticles from Lot D suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot D are in Table 1.

FIG. IP are an aggregated microparticles from Lot D suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot D are in Table 1.

FIG. 2A are an aggregated microparticles from Lot F suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot F are in Table 1.

FIG. 2B are an aggregated microparticles from Lot F suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot F are in Table 1.

FIG. 2C are an aggregated microparticles from Lot F suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot F are in Table 1.

FIG. 2D are an aggregated microparticles from Lot F suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot F are in Table 1.

FIG. 2E are an aggregated microparticles from Lot G suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot G are in Table 1.

FIG. 2F are an aggregated microparticles from Lot G suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot G are in Table 1.

FIG. 2G are an aggregated microparticles from Lot G suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot G are in Table 1.

FIG. 2H are an aggregated microparticles from Lot G suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot G are in Table 1.

FIG. 21 are an aggregated microparticles from Lot H suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot H are in Table 1.

FIG. 2J are an aggregated microparticles from Lot H suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 15 minutes as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot H are in Table 1.

FIG. 2K are an aggregated microparticles from Lot H suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot H are in Table 1.

FIG. 2L are an aggregated microparticles from Lot H suspended in 0.0625% sodium hyaluronate at a concentration of 400 mg/mL that have been incubated for 2 hours as described in the test tube assay of Example 2. The image was taken post-roll. The surface treatment conditions for Lot H are in Table 1.

FIG. 3 A are an aggregated microparticles from Lot F suspended in sodium hyaluronate that have been incubated for 5 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot F are in Table 1 and the % of UV transmittance is in Table 3. The arrow indicates dispersed microparticles. FIG. 3B are an aggregated microparticles from Lot F suspended in sodium hyaluronate that have been incubated for 10 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot F are in Table 1 and the % of UV transmittance is in Table 3.

FIG. 3C are an aggregated microparticles from Lot I suspended in sodium hyaluronate that have been incubated for 5 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot I are in Table 1 and the % of UV transmittance is in Table 3. The arrow indicates dispersed microparticles.

FIG. 3D are an aggregated microparticles from Lot I suspended in sodium hyaluronate that have been incubated for 10 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot I are in Table 1 and the % of UV transmittance is in Table 3.

FIG. 3E are an aggregated microparticles from Lot J suspended in sodium hyaluronate that have been incubated for 5 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot J are in Table 1 and the % of UV transmittance is in Table 3.

FIG. 3F are an aggregated microparticles from Lot J suspended in sodium hyaluronate that have been incubated for 10 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot J are in Table 1 and the % of UV transmittance is in Table 3.

FIG. 3G are an aggregated microparticles from Lot K suspended in sodium hyaluronate that have been incubated for 5 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot K are in Table 1 and the % of UV transmittance is in Table 3. The arrow indicates dispersed microparticles.

FIG. 3H are an aggregated microparticles from Lot K suspended in sodium hyaluronate that have been incubated for 10 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot K are in Table 1 and the % of UV transmittance is in Table 3.

FIG. 4A are an aggregated microparticles from Lot J suspended in sodium hyaluronate that have been incubated for 5 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot J are in Table 1 and the % of UV transmittance is in Table 4.

FIG. 4B are an aggregated microparticles from Lot J suspended in sodium hyaluronate that have been incubated for 10 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot J are in Table 1 and the % of UV transmittance is in Table 4.

FIG. 5A are an aggregated microparticles from Lot M suspended in sodium hyaluronate that have been incubated for 5 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot M are in Table 1 and the % of UV transmittance is in Table 4.

FIG. 5B are an aggregated microparticles from Lot M suspended in sodium hyaluronate that have been incubated for 10 minutes as described in the flow cell evaluation assay of Example 2. The surface treatment conditions for Lot M are in Table 1 and the % of UV transmittance is in Table 4.

FIG. 6A are an aggregated microparticles from Lot L suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot L are in Table 7.

FIG. 6B are an aggregated microparticles from Lot L suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot L are in Table 7.

FIG. 6C are an aggregated microparticles from Lot L suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot L are in Table 7.

FIG. 6D are an aggregated microparticles from Lot L suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot L are in Table 7. FIG. 6E are an aggregated microparticles from Lot M suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot M are in Table 7.

FIG. 6F are an aggregated microparticles from Lot M suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot M are in Table 7.

FIG. 6G are an aggregated microparticles from Lot M suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot M are in Table 7.

FIG. 6H are an aggregated microparticles from Lot M suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot M are in Table 7.

FIG. 61 are an aggregated microparticles from Lot N suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot N are in Table 7.

FIG. 6J are an aggregated microparticles from Lot N suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot N are in Table 7.

FIG. 6K are an aggregated microparticles from Lot N suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot N are in Table 7.

FIG. 6L are an aggregated microparticles from Lot N suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot N are in Table 7.

FIG. 6M are an aggregated microparticles from Lot O suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot O are in Table 7.

FIG. 6N are an aggregated microparticles from Lot O suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot O are in Table 7.

FIG. 60 are an aggregated microparticles from Lot O suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot O are in Table 7.

FIG. 6P are an aggregated microparticles from Lot O suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot O are in Table 7.

FIG. 6Q are an aggregated microparticles from Lot P suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot P are in Table 7.

FIG. 6R are an aggregated microparticles from Lot P suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot P are in Table 7.

FIG. 6S are an aggregated microparticles from Lot P suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken before oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot P are in Table 7. FIG. 6T are an aggregated microparticles from Lot P suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken after oscillation as described in the test tube assay of Example 3. The surface treatment conditions for Lot P are in Table 7.

FIG. 7A are an aggregated microparticles from Lot T suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken before oscillation as described in the test tube assay of Example 4. The surface treatment conditions for Lot T are in Table 8.

FIG. 7B are an aggregated microparticles from Lot T suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken after oscillation as described in the test tube assay of Example 4. The surface treatment conditions for Lot T are in Table 8.

FIG. 7C are an aggregated microparticles from Lot T suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken before oscillation as described in the test tube assay of Example 4. The surface treatment conditions for Lot T are in Table 8.

FIG. 7D are an aggregated microparticles from Lot T suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 2 hours. The image was taken after oscillation as described in the test tube assay of Example 4. The surface treatment conditions for Lot T are in Table 8.

FIG. 7E are an aggregated microparticles from Lot S suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken before oscillation as described in the test tube assay of Example 4. The surface treatment conditions for Lot S are in Table 8.

FIG. 7F are an aggregated microparticles from Lot S suspended in 0.125% sodium hyaluronate at a concentration of 200 mg/mL that have been incubated for 15 minutes. The image was taken after oscillation as described in the test tube assay of Example 4. The surface treatment conditions for Lot S are in Table 8.

FIG. 8 is an image of a polymeric implant comprising PLA and timolol-bis-N,0-glycolic acid-acetyl PLA (n=4) (Compound A) on a ruler prepared by solvent casting into a water bath as described in Example 5. The implant is approximately 1 cm long and has a diameter of 196.10 pm, which is small enough for insertion using a 27-guage thin-walled needle.

FIG. 9 is an image of a polymeric implant comprising PLA, PLGA, and PEG and timolol- bis-N,0-glycolic acid-acetyl PLA (n=4) (Compound A) in the shape of a rectangular prism made by the powder compression method as described in Example 5. The pellet has a dimeter of 13 mm.

FIG. 10 is an image of an implant comprising timolol -bis-N,0-gly colic acid-acetyl PLA (n=4) (Compound A) in a phosphate buffered saline obtained from the pellet in FIG. 9 using a razor blade as described in Example 5. Implants obtained by this method are typically smaller with widths ranging from 400 to 1000 um, lengths not more than 10 mm, and heights ranging from 400 to 1000 um.

FIG. 11 is an image of a non-sintered pellet (left) and a sintered pellet (right) comprising timolol-bis-N,0-glycolic acid-acetyl PLA (n=4) (Compound A) and PLA, PLGA, and PEG. As described in Example 5, the sintered pellet was heated at approximately 60 °C for 10 minutes, while the non-sintered pellet was not. The image was taken prior to oscillation to test the mechanical strength of both pellets and sintering improved the mechanical strength of the pellet.

FIG. 12 is an image of a sintered implant comprising timolol-bis-N,0-glycolic acid-acetyl PLA (n=4) (Compound A) that has been made smaller using a razor blade as described in Example 5. The implant has dimensions of 6.9 mm L x 0.9 mm H x 1 mm W.

FIG. 13 is an in vitro drug release profile of implants comprising Compound A with different diameters (0.29 mm, 0.35 mm, and 0.62 mm). As described in Example 6, the diameter of the impact on release rate. The x-axis is time measured in days and the y-axis is cumulative release measured in percent.

FIG. 14 is an in vitro drug release profile of implants with different drug loading of Compound A (45%, 58%, 70%, and 90%). As described in Example 6, the release rate is slightly more linear and durable when the drug load is higher. The x-axis is time measured in days and the y-axis is cumulative release measured in percent.

FIG. 15 is an in vitro drug release profile of implants encapsulating Compound A with different polymeric compositions. As described in Example 6, the replacement of PLGA 85:15 5.5A (Lot 9) with PLGA 5050 2A (Lot 11 and Lot 12) resulted in accelerating the overall release rate and shortening the duration of the release. The x-axis is time measured in days and the y-axis is cumulative release measured in percent. FIG. 16 is an image of an implant prepared as described in Example 7 shown next to a dime for scale. The implant is approximately 6 mm in length and approximately 0.5 mm in diameter.

FIG. 17 is an in vitro drug release profile of implants formulated with Compound A, timolol maleate, and both Compound A and timolol maleate. As described in Example 8, the dual API implants formulated with both Compound A and timolol maleate provided a more controlled release performance compared to implants formulated with only Compound or timolol maleate. The x-axis is time measured in days and the y-axis is cumulative release measured in percent.

FIG. 18 is an in vitro drug release profile of implants encapsulating Compound A and timolol maleate with different polymeric compositions. As described in Example 8, the implant with PLGA, PLA, and PLGA-PEG resulted in a long release duration than the implant with only PLGA and PLGA-PEG.

FIG. 19 are representative images of the evaluation of particle aggregation in a test-tube in vitro aggregation assay. As described in Example 12, the incorporation of benzyl alcohol in the diluent of the suspension of microparticles significantly improved particle aggregation at the 5- and 10-minute incubation timepoint.

FIG. 20 are representative images of the evaluation of particle aggregation in an artificial vitreous model. As described in Example 12, the incorporation of benzyl alcohol in the diluent of the suspension of microparticles significantly improved particle aggregation at the 0- and 5 -minute incubation timepoint.

FIG. 21 is an in vitro drug release profile of microparticle aggregates suspended in diluent with and without benzyl alcohol. As described in Example 13, there is no significant difference in the drug release, including the initial burst release, of microparticle aggregates suspended with and without benzyl alcohol.

DETAILED DESCRIPTION

The present invention provides new controlled release implant or microparticle formulations with advantageous properties that comprise a prodrug of timolol and are suitable for long-term ocular therapy. Due to the high solubility of timolol maleate in aqueous medium, it is difficult to formulate an implant or microparticle comprising timolol or a pharmaceutically acceptable salt thereof that does not exhibit high burst release within hours or even one day. It is especially hard to develop high drug loaded formulations of timolol because quickly after the formulation contacts the aqueous medium, surface timolol or timolol close to the surface immediately diffuses from the formulation, resulting in burst release.

It has been surprisingly discovered that by formulating timolol or a pharmaceutically acceptable salt thereof with a prodrug of timolol of Formula I in an implant or microparticle as further described herein, linear, sustained release of timolol or a pharmaceutically acceptable salt thereof and the timolol prodrug of Formula I can be achieved, and the release can last for greater than three months. In certain embodiments, the implant or microparticle provides sustained release of timolol and the prodrug of Formula I of greater than four months, greater than five months, greater than six months, or even greater than seven or eight months or more.

The present invention also provides implants or microparticles comprising a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof with drug loading of greater than 40%, 50%, 60%, 70%, 80% by weight, and even as high as 90% or 100% by weight that release the timolol prodrug in a linear fashion without exhibiting burst release.

In certain embodiments, the biodegradable implant is polymeric, and the polymer comprises no more than about 10, no more than about 20, no more than about 30, no more than about 40, no more than about 50, or no more than about 60 weight percent of the implant with the balance of the weight being a compound of Formula I or a pharmaceutically acceptable salt thereof or other non-active agents dispersed in the biocompatible biodegradable polymer.

In certain embodiments, the biodegradable implant is polymeric, and the polymer comprises no more than about 70, no more than about 80, no more than about 90, or no more than about 95, weight percent of the implant with the balance of the weight being a compound of Formula I or a pharmaceutically acceptable salt thereof or other non-active agents dispersed in the biocompatible biodegradable polymer.

In certain embodiments, the non-active agent is a plasticizer, including but not limited to, benzyl alcohol, benzyl benzoate, and triethyl citrate. In one embodiment, the plasticizer is benzyl alcohol.

In certain embodiments, the weight percent of the timolol prodrug of Formula I is between about 40% and about 60% with the weight percent of timolol or a pharmaceutically acceptable salt thereof between about 5% and 25% with the balance of the weight being at least one polymer. In one embodiment, the biodegradable implant (or insert) does not include a polymer, but instead the implant is made from the compound of Formula I or a pharmaceutically acceptable salt thereof with the balance of the weight being a non-active agent or excipient, or a second biologically active compound. In one embodiment, the implant is non-polymeric and the compound of Formula I or a pharmaceutically acceptable salt thereof comprises about 100 weight percent of the implant.

In an alternative embodiment, a durable ocular implant comprising both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof is provided. In certain embodiments, the biodegradable implant is polymeric and the polymer comprises no more than about 10, no more than about 20, no more than about 30, no more than about 40, no more than about 50, or no more than about 60 weight percent of the implant with the balance of the weight being a compound of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof or other non-active agents dispersed in the biocompatible biodegradable polymer. In certain embodiment, the implant is non-polymeric and the compound of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof comprises about 100 weight percent of the implant.

In a further embodiment, a durable ocular implant comprising (a) a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof; (b) timolol and a pharmaceutically acceptable salt thereof; and (c) timolol is provided. In certain embodiments, the biodegradable implant is polymeric and the polymer comprises no more than about 10, no more than about 20, no more than about 30, no more than about 40, no more than about 50, or no more than about 60 weight percent of the implant with the balance of the weight being a compound of Formula I or a pharmaceutically acceptable salt thereof, timolol, and timolol and a pharmaceutically acceptable salt thereof or other non-active agents dispersed in the biocompatible biodegradable polymer. In certain embodiment, the implant is non-polymeric and the compound of Formula I or a pharmaceutically acceptable salt thereof, timolol, and timolol and a pharmaceutically acceptable salt thereof comprises about 100 weight percent of the implant.

In certain embodiments the polymeric or non-polymeric implant exhibits a hardness rating of at least about 5 gram-force needed to compress the implant at 30% of strain when tested in vitro. In certain embodiments, the implant exhibits a hardness rating of at least about 10 gram-force, 15 gram -force, 20 gram-force, 40 gram-force, 50 gram -force, 70 gram-force, 100 gram -force, 120 gram-force, 150 gram-force, 170 gram-force, or more. In certain embodiments, the hardness is measured in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

In an alternative aspect, the formulation is a microparticle formulation, and in some embodiments, the microparticles have been surface-treated and form an aggregated microparticle in vivo , for example a pellet or a depot.

In alternative embodiments, the durable controlled release formulation of Formula I is in a biodegradable microparticle suitable for long-term ocular therapy and can be prepared with a drug (i.e., Formula I) load of about 42% by weight or greater, for example about 43% or greater, about 44% or greater, about 45% or greater, about 50% or greater, about 60% or greater, about 75% or greater, about 90% or greater or even as high as about 100% by weight. In certain embodiments, the controlled-release formulation comprises a biodegradable polymer such as PLGA, PLA, PLGA-PEG, PLA-PEG or a combination thereof.

In some embodiments, microparticles of the present invention have been mildly surface- treated, for example with a surface-treatment agent comprising an aqueous base in an organic solvent, such as NaOH in EtOH, and these microparticles aggregate in vivo to an aggregated microparticle depot of at least 500 pm. In certain embodiments, the concentration of the NaOH solution is between about 2.0 mM and about 12 mM. In certain embodiments, the percentage of EtOH in the NaOH/EtOH solution is at least about 10%, about 30%, about 40%, about 45%, about 50%, about 55%, or about 70%.

In certain embodiments, the microparticles of the present invention with drug loads ranging from about 42%-100% by weight form an aggregated microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10 gram -force, and in some embodiments, at least about 20, 40, 50, 70, and even 100 or greater gram-force needed to compress the depot at 30% of strain. In certain embodiments, the hardness is measured in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

I. TERMINOLOGY

Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this presently described subject matter belongs.

Compounds are described using standard nomenclature. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this invention belongs.

The terms “a” and “an” do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced items.

Recitation of ranges of values are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. The endpoints of all ranges are included within the range and are independently combinable. All methods described herein can be performed in a suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of examples, or exemplary language (e.g., “such as”), is intended merely to better illustrate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed.

The term “carrier” refers to a diluent, excipient, or vehicle.

A “dosage form” means a unit of administration of a composition that includes a surface treated microparticle and a therapeutically active compound or an implant and a therapeutically active compound. Examples of dosage forms include injections, suspensions, liquids, emulsions, implants, particles, spheres, topical, gel, mucosal, and the like. A “dosage form” can also include, for example, a surface treated microparticle comprising a pharmaceutically active compound in a carrier.

The term “microparticle” means a particle whose size is measured in micrometers (pm). Typically, the microparticle has an average diameter of from about 0.5 or 1 pm to 100 or 150 pm. In some embodiments, the microparticle has an average diameter of from about 1 pm to 60 pm, for instance from about 1 pm to 40 pm; from about 10 pm to 40 pm; from about 20 pm to 40 pm; from about 25 pm to 40 pm; from about 25 pm to about 30 pm; from about 20 pm to 35 pm. For example, the microparticle may have an average diameter of from 20 pm to 40 pm, and in certain embodiments, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 or 33. As used herein, the term “microsphere” means a substantially spherical microparticle.

A “patient” or “host” or “subject” is typically a human, however, may be more generally a mammal. In an alternative embodiment it can refer to, for example, a cow, sheep, goat, horse, dog, cat, rabbit, rat, mouse, bird and the like. Unless otherwise stated, the subject is a human.

The term “mild” or “mildly” when used to describe the surface modification of the microparticles means that the modification (typically the removal, or partial removal, of surfactant from the surface, as opposed to the inner core, of the particle) is less severe, pronounced or extensive than when carried out at room temperature with the otherwise same conditions. In general, the surface modification of the solid microparticles of the present invention is carried out in a manner that does not create significant channels or large pores that would significantly accelerate the degradation of the microparticle in vivo , yet serves to soften and decrease the hydrophilicity of the surface to facilitate in vivo aggregation.

The term “solid” as used to characterize the mildly surface treated microparticle means that the particle is substantially continuous in material structure as opposed to heterogeneous with significant channels and large pores that would undesirably shorten the time of biodegradation.

The term “sonicate” means to subject the microparticle suspension to ultrasonic vibration or high frequency sound waves.

The term “vortex” means to mix by means of a rapid whirling or circular motion.

“Hardness,” is a measure of resistance to deformation in units of the gram-force (gf) required to compress the microparticle aggregate depot at 30% of strain. In certain embodiments, the aggregated microparticle depot of the present invention exhibits a hardness of at least about 40 gram-force, at least 50 gram-force, 70 gram-force, at least about 100 gram-force, or at least about 150 gram-force. In one embodiment, hardness is measured via a Texture Analyzer.

“Gram-force” is a metric unit of force (gf) and is used in this application as a measure of microparticle hardness. The term “additive” is used to describe any reagent or solvent that increases the plasticity or flexibility of a polymer, decreases the viscosity or the glass transition temperature of a polymer, or partially dissolves a polymer. In some embodiments, the additive is a plasticizer. Non-limiting examples of additives of the present invention include triethyl citrate, benzyl alcohol, polyethylene glycol, N-methyl-2-pyrrolidone (NMP), 2-pyrrolidone, DMSO, triacetin, benzyl acetate, benzyl benzoate, acetyltributyl citrate, dibutyl sebacate, dimethylphthalate, tributyl O-acetylcitrate, ethanol, methanol, polysorbate 80, ethyl acetate, propylene carbonate, isopropyl acetate, methyl acetate, methyl ethyl ketone, butyl lactate, and isovaleric acid.

“Aggregated microparticle depot” (or alternatively “aggregated microparticle pellet”, or “aggregated microparticle”) as used herein, is a solid aggregation of individual microparticles wherein the individual microparticles prior to aggregation typically have a mean diameter between about, for example, 10 pm and about 60 or 75 microns, and more typically between about 20 and about 40 microns (or between about 15 and about 40 or between about 25 and about 40 microns or 20 and 30 microns). The aggregated microparticle depot of the present invention are distinct from ocular implants which are injected in vivo in an already formed shape, and also are distinct from microparticles that are held together by a depot-forming material such as a gel, or other material intended to hold the microparticles together other than the microparticles themselves.

“Implant” refers to a polymeric device or element that is structured, sized, or otherwise configured to be implanted, for example, by injection or surgical implantation, in a specific region of the body so as to provide therapeutic benefit by releasing one or more active agents over an extended period of time at the site of implantation. For example, intraocular implants are polymeric devices or elements that are structured, sized, or otherwise configured to be placed in the eye, for example, by injection or surgical implantation, and to treat one or more diseases or disorders of the eye by releasing one or more drugs over an extended period.

“Light transmittance” is the percentage of light that is transmitted through the solution of microparticles suspended in a diluent, for example hyaluronate solution as described in Example 2. In certain embodiments, a solution of microparticles suspended in a diluent has a light transmittance of greater than about 90%, greater than about 92%, greater than about 94%, greater than about 96%, greater than 98%, or greater than 99%. II. Implants

In one embodiment, the present invention provides biodegradable implants that encapsulate and/or have dispersed therein a compound of Formula I or a pharmaceutically acceptable salt thereof. In certain embodiments, the present invention provides biodegradable implants that encapsulate and/or have dispersed therein both a compound of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example, timolol maleate. In one embodiment, the implant comprises a timolol prodrug of Formula I or a pharmaceutically acceptable salt, timolol, and timolol and a pharmaceutically acceptable salt. In one embodiment, the timolol or a pharmaceutically acceptable salt is timolol maleate.

In preferred embodiments, the implants are intraocular implants. Suitable implants include, but are not limited to, rods, discs, pellets, and wafers. In one embodiment, the implant is formed of any of the biodegradable polymers described herein. In one embodiment, the implant comprises poly lactic-co-gly colic acid (PLGA) and/or polylactic acid (PLA). In one embodiment, the implant further comprises PLGA conjugated to a polyalkylene glycol, such as polyethylene glycol (PEG).

The composition of the polymer matrix may be selected based on the time required for in vivo stability, i.e., that time required for distribution of timolol or a pharmaceutically acceptable salt thereof and/or the compound of Formula I or a pharmaceutically acceptable salt thereof to the site where delivery is desired, and the time desired for delivery. The implants may be of any geometry such as fibers, sheets, films, microspheres, spheres, prisms, circular discs, rods, or plaques.

In certain embodiments, timolol or a pharmaceutically acceptable salt thereof and/or a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof is delivered in an implant that is a blend of two polymers, for example (i) a PLGA polymer or PLA polymer as described herein and (ii) a PLGA-PEG or PLA-PEG copolymer. In another embodiment, the implant is a blend of three polymers, such as, for example, (i) a PLGA polymer; (ii) a PLA polymer; and (iii) a copolymer of PLGA-PEG or PLA-PEG. In one embodiment, the implant is a blend of (i) a PLGA polymer; (ii) a PLGA polymer that has a different ratio of lactide and glycolide monomers than the PLGA in (i); and (iii) a PLGA-PEG or PLA-PEG copolymer. In an additional embodiment, the implant is a blend of (i) a PLA polymer; (ii) a PLGA polymer; (iii) a PLGA polymer that has a different ratio of lactide and glycolide monomers than the PLGA in (ii); and (iv) a PLGA-PEG or PLA-PEG copolymer. Any ratio of lactide and glycolide in the PLGA can be used that achieves the desired therapeutic effect. In certain illustrative non-limiting embodiments, the ratio of PLA to PLGA by weight in a polymer blend as described is about 77/22, 69/30, 49/50, 54/45, 59/40, 64/35, 69/30, 74/25, 79/20, 84/15, 89/10, 94/5, or 99/1.

In certain embodiments, a blend of two polymers has (i) PLGA and (ii) PLGA with a different ratio of lactide and glycolide monomers than PLGA in (i) wherein the ratio by weight is about 74/20/5 by weight, about 69/20/10 by weight, about 69/25/5 by weight, or about 64/20/15 by weight. In certain embodiments, the PLGA in (i) has a ratio of lactide to glycolide of about 85/15, about 75/25, or about 50/50. In certain embodiments the PLGA in (ii) has a ratio of lactide to glycolide of about 85/15, about 75/25, or about 50/50.

In certain embodiments, a blend of three polymers has (i) PLA (ii) PLGA (iii) PLGA with a different ratio of lactide and glycolide monomers than PLGA in (ii) wherein the ratio by weight is about 74/20/5 by weight, about 69/20/10 by weight, about 69/25/5 by weight, or about 64/20/15 by weight. In certain embodiments, the PLGA in (ii) has a ratio of lactide to glycolide of about 85/15, about 75/25, or about 50/50. In certain embodiments the PLGA in (iii) has a ratio of lactide to glycolide of about 85/15, about 75/25, or about 50/50.

In certain aspects, the drug may be delivered in an implant that is a blend of PLGA or PLA and PEG-PLGA, including but not limited to (i) PLGA + approximately by weight 1% PEG-PLGA or (ii) PLA + approximately by weight 1% PEG-PLGA. In certain aspects, the drug may be delivered in a blend of (iii) PLGA/PLA + approximately by weight 1% PEG-PLGA. In certain embodiments, the blend of PLA, PLGA, or PLA/PGA with PLGA-PEG contains approximately from about 0.5% to about 10% by weight of a PEG-PLGA, from about 0.5% to about 5% by weight of a PEG-PLGA, from about 0.5% to about 4% by weight of a PEG-PLGA, from about 0.5% to about 3% by weight of a PEG-PLGA, from about 1.0% to about 3.0% by weight of a PEG-PLGA, from about 0.1% to about 10% of a PEG-PLGA, from about 0.1% to about 5% of a PEG-PLGA, from about 0.1% to about 1% PEG-PLGA, or from about 0.1% to about 2% PEG-PLGA.

In certain non-limiting embodiments, the ratio by weight percent of PLGA to PEG-PLGA in a two polymer blend as described is about or at least about 40/1, 45/1, 50/1, 55/1, 60/1, 65/1, 70/1, 75/1, 80/1, 85/1, 90/1, 95/1, 96/1, 97/1, 98/1, 99/1. The PLGA can be acid or ester capped. In non-limiting aspects, the drug can be delivered in a two polymer blend of PLGA75:25 4A + approximately 1% PEG-PLGA50:50; PLGA85:15 5A + approximately 1% PEG-PLGA5050; PLGA75:25 6E + approximately 1% PEG-PLGA50:50; or PLGA50:50 2A + approximately 1% PEG-PLGA50:50.

In certain non -limiting embodiments, the ratio by weight percent of PLA/PLGA-PEG in a polymer blend as described is about or at least about 40/1, 45/1, 50/1, 55/1, 60/1, 65/1, 70/1, 75/1, 80/1, 85/1, 90/1, 95/1, 96/1, 97/1, 98/1, 99/1. The PLA can be acid capped or ester capped. In cetain aspects, the PLA is PLA 4.5A. In non-limiting aspects, the drug is delivered in a blend of PLA 4.5A + 1% PEG-PLGA.

The PEG segment of the PEG-PLGA may have, for example, in non-limiting embodiments, a molecular weight of at least about or about 1 kDa, 2 kDa, 3 kDa, 4 kDa, 5 kDa, 6 kDa, 7 kDa, 8 kDa, 9 kDa, or 10 kDa, and typically not greater than 10 kDa, 15 kDa, 20 kDa, or 50 kDa, or in some embodiments, 6 kDa, 7 kDa, 8 kDa, or 9kDa. In certain embodiment, the PEG segment of the PEG-PLGA has a molecular weight between about 3 kDa and about 7 kDa or between about 2 kDa and about 7 kDa. Non-limiting examples of the PLGA segment of the PEG-PLGA is PLGA50:50, PLGA75:25, or PLGA85:15. In one embodiment, the PEG-PLGA segment is PEG (5 kDa)-PLGA50:50.

When the drug is delivered in a blend of PLGA + PEG-PLGA, any ratio of lactide and glycolide in the PLGA or the PLGA-PEG can be used that achieves the desired therapeutic effect. Non-limiting illustrative embodiments of the ratio of lactide/glycolide in the PLGA or PLGA-PEG are about or at least about 5/95, 10/90, 15/85, 20/80, 25/75, 30/70, 35/65, 40/60, 45/55, 50/50, 55/45, 60/40, 65/35, 70/30, 75/25, 80/20, 85/15, 90/10, or 95/5 by weight percent. In one embodiment, the PLGA is a block co-polymer, for example, diblock, triblock, multiblock, or star shaped block. In one embodiment, the PLGA is a random co-polymer. In certain aspects, the PLGA is PLGA75:25 4A; PLGA85:15 5A; PLGA75:25 6E; or PLGA50:502A.

In certain embodiments, the biodegradable polymer(s) comprises no more than about 10, no more than about 20, no more than about 30, no more than about 40, no more than about 50, no more than about 60, no more than about 70, no more than about 80, or no more than about 90 weight percent of the implant with the balance of the weight being timolol or a pharmaceutically acceptable salt and/or a compound of Formula I or a pharmaceutically acceptable salt thereof or other non-active agents dispersed in the biocompatible biodegradable polymer.

In certain embodiments, the non-active agent is a plasticizer that increases the flexibility and processability of the implant. Non-limiting examples of the non-active agent include benzyl alcohol, benzyl benzoate, ethyl heptanoate, propylene carbonate, triacetin, and triethyl citrate. In one embodiment, the non-active agent is benzyl alcohol.

Intraocular implants are generally biocompatible with physiological conditions of an eye and do not cause adverse side effects. Generally, intraocular implants may be placed in an eye without disrupting vision of the eye.

In certain embodiments the implants of the present invention comprise about 35-55% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and 15-30% by weight timolol or a pharmaceutically acceptable salt thereof with the remaining weight being at least one polymer and non-active excipients.

In certain embodiments the implants of the present invention comprise about 50-70% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and 5-20% by weight timolol or a pharmaceutically acceptable salt thereof with the remaining weight being at least one polymer and non-active excipients.

In certain embodiments the implants of the present invention comprise about 1-30% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and 1-30% by weight timolol or a pharmaceutically acceptable salt thereof with the remaining weight being at least one polymer and non-active excipients.

In certain embodiments the implants of the present invention comprise about 1-30% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and 30-60% by weight timolol or a pharmaceutically acceptable salt thereof with the remaining weight being at least one polymer and non-active excipients.

In certain embodiments the implants of the present invention comprise about 30-60% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and 1-30% by weight timolol or a pharmaceutically acceptable salt thereof with the remaining weight being at least one polymer and non-active excipients.

In certain embodiments, the implants of the present invention are non-polymeric and comprise both timolol or a pharmaceutically acceptable salt thereof and a prodrug of timolol of Formula I or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is non-polymeric and comprises about at least about 50% by weight of timolol or a pharmaceutically acceptable salt thereof and no greater than 50% by weight of timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is at least about 40% timolol or a pharmaceutically acceptable salt thereof and no greater than about 60% timolol prodrug or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is at least about 30% timolol or a pharmaceutically acceptable salt thereof and no greater than about 70% timolol prodrug or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is at least about 20% timolol or a pharmaceutically acceptable salt thereof and no greater than about 80% timolol prodrug or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is at least about 10% timolol or a pharmaceutically acceptable salt thereof and no greater than about 90% timolol prodrug or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is at least about 60% timolol or a pharmaceutically acceptable salt thereof and no greater than about 40% timolol prodrug or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is at least about 70% timolol or a pharmaceutically acceptable salt thereof and no greater than about 30% timolol prodrug or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is at least about 80% timolol or a pharmaceutically acceptable salt thereof and no greater than about 20% timolol prodrug or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant is at least about 90% timolol or a pharmaceutically acceptable salt thereof and no greater than about 10% timolol prodrug or a pharmaceutically acceptable salt thereof.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 5% by weight (with or without salt) to about 95% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 10% by weight (with or without salt) to about 90% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 15% by weight (with or without salt) to about 85% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 20% by weight (with or without salt) to about 80% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 25% by weight (with or without salt) to about 75% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 30% by weight (with or without salt) to about 70% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 35% by weight (with or without salt) to about 65% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 40% by weight (with or without salt) to about 60% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 45% by weight (with or without salt) to about 55% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 50% by weight (with or without salt) to about 50% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 55% by weight (with or without salt) to about 45% or less (with or without salt) by weight. In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 60% by weight (with or without salt) to about 40% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 65% by weight (with or without salt) to about 35% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 70% by weight (with or without salt) to about 30% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 75% by weight (with or without salt) to about 25% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 80% by weight (with or without salt) to about 20% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 85% by weight (with or without salt) to about 15% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 90% by weight (with or without salt) to about 10% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the implants of the present invention is selected from up to about 95% by weight (with or without salt) to about 5% or less (with or without salt) by weight.

In one embodiment, the implant comprises (a) timolol and a pharmaceutically acceptable salt thereof; (b) timolol; and (c) a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof. In one embodiment, the implant comprises up to about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof with the remaining balance being timolol and a pharmaceutically salt thereof, timolol, at least one polymer, and non-active excipients. In one embodiment, the implant comprises up to about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof with the remaining balance being timolol and a pharmaceutically salt thereof, timolol, and non-active excipients.

Implant size is determined by factors such as toleration for the implant, location of the implant, size limitations in view of the proposed method of implant insertion, and/or ease of handling. The size and shape of the implant can also be used to control the rate of release, period of treatment, and drug concentration at the site of implantation. Larger implants will deliver a proportionately larger dose, but depending on the surface to mass ratio, may have a slower release rate. The particular size and geometry of the implant are chosen to suit the site of implantation.

The vitreous chamber in humans is able to accommodate relatively large implants of varying geometries, having a length of about 1 mm to about 15 mm and a diameter of between about 100 pm and about 1000 pm. In certain embodiments, the implant has a length of at least about 2 mm to no less than about 12 mm, at least about 3 mm to about 10 mm or less, at least about 4 mm to about 7 mm or less, or at least about 5 mm to about 6 mm or less. In certain embodiments, the diameter is between at least about 100 pm to about 800 pm or less, at least about 200 pm to about 600 pm or less, or between at least about 300 pm to about 500 pm or less. In certain embodiments, the implant has a diameter between at least about 200 pm and 600 pm or less and length between at least about 3 mm and 10 mm or less. In an alternative embodiment, the implant has a diameter between about at least 300 pm and 600 pm or less and length between about at least 1 mm and 10 mm or less.

In certain embodiments, the implant is in the shape of a cylindrical pellet with a width ranging from at least about 400 pm to about 1200 pm or less, a length of not more than 15 mm, and a height ranging from at least 400 pm to 1200 pm or less. In certain embodiments, the cylindrical pellet has a width between about at least 400 pm to about 600 pm or less, at least about 500 pm to about 700 pm or less, at least about 600 pm to about 800 pm or less, at least about 700 pm to about 900 pm or less, at least about 800 pm to about 1000 pm or less, or at least about 900 pm to about 1100 pm or less. In certain embodiments, the cylindrical pellet has a length of not more than about 15 mm, not more than about 12 mm, not more than about 10 mm, not more than about 9 mm, not more than about 8 mm, not more than about 7 mm, not more than about 6 mm, not more than about 5 mm, not more than about 4 mm, not more than about 3 mm, not more than about 2 mm, or not more than about 1 mm. In certain embodiments, the cylindrical pellet has a width between about at least 400 pm to about 600 pm or less, about at least 500 pm to about 700 pm or less, at least about 600 pm to about 800 pm or less, at least about 700 pm to about 900 pm or less, at least about 800 pm to about 1000 pm or less, or about at least 900 pm to about 1100 pm or less.

In certain embodiments, the cylindrical pellet has a height between at least about 700 pm and about 1000 pm or less, a length of not more than about 7 mm, and a width between at least about 800 pm and about 1100 pm or less. In certain embodiments, the cylindrical pellet has a height between at least about 800 pm and about 950 pm or less, a length of not more than about 7 mm, and a width between at least about 900 pm and 1000 pm or less. In one particular embodiment, the cylindrical pellet has a height of about 900 pm, a length of about 7 mm, and a width of about 1000 pm.

In certain embodiments, the implant is a rod with a diameter of between at least about 550 pm and about 50 pm or less. In certain embodiments, the implant is a rod with a diameter of between about at least 550 pm and about 100 pm or less, between at least about 450 pm and about 150 pm or less, between at least about 400 pm and about 200 pm or less, or between at least about 350 pm and about 250 pm or less. In certain embodiments, the implant is a rod with a diameter of between at least about 500 pm and about 350 pm or less. In certain embodiments, the implant is a rod with a diameter of between at least about 500 pm and about 400 pm or less or between at least about 400 pm and about 300 pm or less. In alternative embodiments, the implant is a rod with a diameter greater than about 550 gm, for example greater than about 575 pm, greater than about 600 pm, greater than about 625 pm, or greater than about 650 pm.

In a further embodiment, the implant is a rod with a length of no greater than about 10 mm, no greater than about 9 mm, no greater than about 8 mm, no greater than about 7 mm, no greater than about 6 mm, no greater than about 5.5 mm, no greater than about 5 mm, no greater than about 4.5 mm, no greater than about 4 mm, no greater than about 3.5 mm, no greater than about 3 mm, no greater than about 2.5 mm, no greater than about 2 mm, no greater than about 1.5 mm, or no greater than about 1 mm.

In certain embodiments, the implant is a rod with a diameter between at least about 550 pm and 100 pm or less, between at least about 500 pm and 300 pm or less, or between at least about 500 pm and 400 pm or less with a length of no greater than 7 mm or 6 mm. In certain embodiments, the implant is a rod with a diameter between at least about 500 pm and about 400 pm or less with a length of no greater than 6 mm.

In certain embodiments, the implant is a rod with a diameter between at least about 400 pm and 100 pm or less, between at least about 400 pm and 200 pm or less, or between at least about 400 pm and 300 pm or less with a length of no greater than 4 mm or 3.5 mm. In certain embodiments, the implant is a rod with a diameter between at least about 400 pm and about 300 pm or less with a length of no greater than 3.5 mm.

In certain embodiments, the implant is a rod with a diameter between at least about 250 pm and 100 pm or less or between about at least 200 pm and 100 pm or less with a length of no greater than about 10 mm. In certain embodiments, the implant is a rod with a diameter between at least about 250 pm and about 150 pm or less with a length of no greater than about 10 mm.

In certain embodiments, the implant, for example the rod or cylindrical pellet, has syringeability with a regular-walled 21-, 22-, 23-, 24-, 25-, 26-, 27-, 28-, 29-, or 30-gauge needle with no clogging of the syringe. In certain embodiments, the implant, for example the rod or cylindrical pellet, has syringeability with a regular-walled 21-, 22-, 23-, 24-, or 25-gauge needle with no clogging of the syringe.

In certain embodiments, the implant, for example the rod, has syringeability with a thin- walled or ultra thin-walled 21-, 22-, 23-, 24-, 25-, 26-, 27-, 28-, 29-, or 30-gauge needle with no clogging of the syringe. In certain embodiments, the implant has syringeability with a thin-walled or ultra thin-walled 27-gauge. In certain embodiments, the implant, for example the rod, has syringeability with a thin-walled or ultra thin-walled 26-, 27-, 28-, 29-, or 30-gauge needle with no clogging of the syringe. In certain embodiments, the implant has syringeability with a thin- walled or ultra thin-walled 27-gauge.

Intraocular implants may also be designed to be least somewhat flexible so as to facilitate both insertion of the implant in the eye, such as in the vitreous humor, and subsequent accommodation of the implant. The total weight of the implant is usually at least about 250 to 5000 pg or less, for example, at least about 500 - 1000 pg or less. In certain embodiments, the intraocular implant has a mass of about 500 pg, 750 pg, or 1000 pg.

In certain embodiments, the implant exhibits a hardness rating in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water of at least 5, and in some embodiments, at least about 10, 15, 20, 30, 40, 50, 60, 70, 75, 100, 120, 150, or more gram-force needed to compress the implant at 30% of strain. In one embodiment, the implant exhibits a hardness rating about at least about 40 gram-force needed to compress the particle at 30% of strain.

In certain embodiments, the biodegradable polymer(s) comprises between about 10 and about 30 weight percent of the implant and the implant exhibits a hardness rating in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water of at least about 40, 50, 60, 70, 75, 100, 120, 150, or more gram-force needed to compress the implant at 30% of strain. In certain embodiments, the implant exhibits a hardness rating about at least about 40 gram-force need to compress the particle at 30% of strain. In certain embodiments, the hardness is measured in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

In certain embodiments, the biodegradable polymer(s) comprises between about 30 and about 50 weight percent of the implant and the implant exhibits a hardness rating in vivo in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water of at least 40, 50, 60, 70, 75, 100, 120, 150, or more gram-force needed to compress the implant at 30% of strain. In one embodiment, the implant exhibits a hardness rating about at least about 40 gram-force need to compress the particle at 30% of strain.

In one embodiment, the implant is non-polymeric and timolol or a pharmaceutically acceptable salt and/or a compound of Formula I or a pharmaceutically acceptable salt thereof comprises between about 85 and about 100 weight percent of the implant with the balance of the weight being non-active agents or excipients. In one embodiment, the compound of Formula I or a pharmaceutically acceptable salt thereof and/or timolol or a pharmaceutically acceptable salt comprise 100 weight percent of the implant. In one embodiment, timolol or a pharmaceutically acceptable salt thereof is timolol maleate.

In one embodiment, the non-polymeric implant comprises between about 85 and about 100 weight percent of timolol or a pharmaceutically acceptable salt and/or a compound of Formula I or a pharmaceutically acceptable salt thereof and exhibits a hardness rating in vivo in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water of at least 5, and in some embodiments, at least about 10, 15, 20, 30, 40, 50, 60, 70, 75, 100, 120, 150, or more gram-force needed to compress the implant at 30% of strain. In one embodiment, the non-polymeric implant comprises about 100 weight percent of timolol or a pharmaceutically acceptable salt and/or a compound of Formula I or a pharmaceutically acceptable salt thereof and exhibits a hardness rating of at least about 40 gram-force needed to compress the implant at 30% of strain.

In certain embodiments, the implant is inserted via a needle, including but not limited to a 21, 22, 23, 24, 25, 26, 27, 29, 30, or 31 gauge needle, which may optionally have a thin or ultra- thin needle wall. In an alternative embodiment, the needle has an inner diameter of between about 100 pm and 1000 pm and a length between about 1 mm and 15 mm. In certain embodiments, the needle has an inner diameter of between about 100 pm and about 300 pm, between about 200 pm and about 400 pm, between about 300 pm and about 500 pm, between about 400 pm and about 700 pm, between about 500 pm and about 800 pm, or between about 600 pm and about 900 pm. In certain embodiments, the needle has a length of about 2 mm to about 12 mm, about 3 mm to about 10 mm, about 5 mm to about 7 mm, or about 6 mm to about 10 mm.

In certain embodiments, the needle has an inner diameter of between about 200 pm and about 600 pm and a length between about 3 mm and 10 mm. In certain embodiments, the needle has an inner diameter of between about 400 mih and about 500 mih and a length between about 4 mm and 6 mm.

In certain embodiments, the implant has a length of between at least about 3 to about 10 mm or less and for every 6 mm of implant, the average dose of the timolol prodrug of Formula 1 ranges from about 0.10 mg to about 1.10 mg. In certain embodiments, the average dose of the timolol prodrug of Formula I for every 6 mm of implant is at least about 0.10 mg, 0.20 mg, 0.30 mg, 0.40 mg. 0.50 mg, 0.60 mg, 0.70 mg, 0.80 mg, 0.90 mg, 1.0 mg, or 1.10 mg.

In certain embodiments, the implant comprises both timolol or a pharmaceutically acceptable salt thereof and a timolol prodrug of Formula I and has a length of between at least about 3 to about 10 mm or less and for every 6 mm of implant, the average dose of the timolol prodrug of Formula 1 ranges from about 0.50 mg to about 1.10 mg and the average dose of timolol ranges from about 0.05 mg to about 0.40 mg. In certain embodiments, the average dose of the timolol prodrug of Formula I for every 6 mm of implant is at least about 0.50 mg, 0.60 mg, 0.70 mg, 0.80 mg, 0.90 mg, 1.0 mg, or 1.10 mg and the average dose of timolol for every 6 mm of implant is at least about 0.05 mg, 0.10 mg, 0.20 mg, 0.30 mg, or 0.40 mg. In certain embodiments, the average dose of the timolol prodrug of Formula I for every 6 mm of implant is at between about 0.60 mg and 0.90 mg and the average dose of timolol for every 6 mm of implant is at between about 0.20 mg and 0.35 mg.

The implants of the present invention provides sustained delivery of timolol or a pharmaceutically acceptable salt and/or a compound of Formula I for at least one month, or at least two months, or at least three months, or at least four months, or at least five months, or at least six months, or at least seven months, or at least eight months, or at least nine months, or at least ten months, or at least eleven months, or at least twelve months. In certain embodiments, timolol or a pharmaceutically acceptable salt thereof is timolol maleate.

In certain embodiments, an implant comprising a compound of Formula I allows a substantially zero or first order release rate of the compound of Formula I from the implant. A zero order release rate is a constant release of the compound of Formula I over a defined time and such release is difficult to achieve using known delivery methods.

The present invention also includes pharmaceutical compositions of the implants as described herein. In certain embodiments, the pharmaceutical composition comprises an additive that improves the flexibility of the implant, for example a plasticizer. In one embodiment, the plasticizer is benzyl alcohol.

In another embodiment, a method for the treatment of an ocular disorder is provided that includes administering to a host in need thereof the polymeric implants described herein that include an effective amount of timolol or a pharmaceutically acceptable salt and/or a compound of Formula I, wherein the implant is injected into the eye and provides sustained drug delivery for at least approximately one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve or more months. In certain embodiments, the solid biodegradable microparticles release about 1 to about 20 percent, about 1 to about 15 percent, about 1 to about 10 percent, or about 5 to 20 percent, for example, up to about 1, 5, 10, 15 or 20 percent, of the therapeutic agent over the first twenty-four- hour period.

Implants can be manufactured using any suitable technique known in the art. Examples of suitable techniques for the preparation of implants include solvent evaporation methods, phase separation methods, interfacial methods, molding methods, injection molding methods, extrusion methods, coextrusion methods, carver press method, die cutting methods, compression, solvent casting, 3D printing and combinations thereof. In one embodiment, the implant is splinted, or exposed to heat, and typically compressed. In one embodiment, the splintered by exposing the pellet to a hot water bath. In one embodiment, implant is not splinted. Suitable methods for the manufacture of implants can be selected in view of many factors including the properties of the polymer/polymers present in the implant, the properties of the one or more drugs present in the implant, and the desired shape and size of the implant. Suitable methods for the preparation of implants are described, for example, in U.S. Pat. No. 4,997,652 and U.S. Patent Application Publication No. US 2010/0124565.

In certain cases, extrusion methods may be used to avoid the need for solvents during implant manufacture. When using extrusion methods, the polymer/polymers and active compound are chosen so as to be stable at the temperatures required for manufacturing, usually at least about 85° C. However, depending on the nature of the polymeric components and the one or more compounds, extrusion methods can employ temperatures of about 25° C to about 150° C, for example, about 65° C to about 130° C. Implants may be coextruded in order to provide a coating covering all or part of the surface of the implant. Such coatings may be erodible or non-erodible, and may be impermeable, semi -permeable, or permeable to the compound, water, or combinations thereof. Such coatings can be used to further control release of the compound from the implant. In one embodiment, the implant is manufactured using hot-melt extrusion wherein the material is subjected to elevated temperature or pressure to cause the material to soften or melt.

Compression methods may be used to make the implants. Compression methods frequently yield implants with faster release rates than extrusion methods. Compression methods may employ pressures of about 50-150 psi, for example, about 70-80 psi, even more for example, about 76 psi, and use temperatures of about 0° C to about 115° C, for example, about 25° C.

In an alternative embodiment, microparticles comprising a timolol prodrug of Formula I are used as the starting material to formulate the implants via, for example, compression, solvent casting, or hot melt extrusion. In this embodiments, pre-mixing in not required because the components are already well-mixed during the microparticle formulation. The drug load of the microparticles used as a starting material can up to about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or even 100% by weight. Example 10 is a non-limiting illustrative example of the process to form an implant from microparticles. In one embodiment, the microparticles are surface -treated as described herein. In one embodiment, the microparticles are not surface-treated.

In certain embodiments, implants of the present invention can also be formulated from (a) microparticles comprising a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and (b) unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof. In one embodiment, the unencapsulated timolol prodrug is micronized.

In one embodiment, these implants are formed via compression, solvent casting, or hot melt extrusion. In certain embodiments, the implant comprises about 0.05 to 0.1%, about 0.1% to 1.0%, about 1.0% to 5.0%, about 5.0% to about 10%, about 10% to about 30% by weight of unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof. In certain embodiments, the implant comprises greater than about 30%, greater than about 40%, or greater than about 50% by weight of unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof.

In other certain embodiments, the implant is formulated from a powder that comprises both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate. In alternative embodiments, the implant is formulated from microparticles that comprise both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate.

In a further alternative embodiment, the implant is formulated from (a) microparticles that comprise a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and/or timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate and (b) unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof. In one embodiment, the unencapsulated timolol prodrug is micronized. Alternatively, the implant is formulated from (a) microparticles that comprise both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate and (b) unencapsulated micronized timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate.

The present invention also includes implants formulated from (a) microparticles that comprise both a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate and (b) unencapsulated timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and micronized timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate. In one embodiment, the unencapsulated timolol prodrug is micronized.

III. Microparticles

In one embodiment, the present invention provides solid microparticles comprising a compound of Formula I or a pharmaceutically acceptable salt thereof and surfactant wherein the microparticles are sufficiently small to be injected in vivo and wherein the compound of Formula I or the pharmaceutically acceptable salt has the structure:

wherein R¹, R², R³, R⁴, x, y, and z are defined herein.

In certain embodiments, the particle is not surface-treated before use.

The present invention also provides solid microparticles comprising both timolol or a pharmaceutically acceptable salt thereof, for example timolol maleate, and a compound of Formula I or a pharmaceutically acceptable salt thereof and surfactant wherein the microparticles are sufficiently small to be injected in vivo. In one embodiment, these microparticles are suitable for long term (for example, up to or at least three month, up to four month, up to five month, up to six months, up to seven months, up to eight months, up to nine months or longer) sustained delivery of timolol or a pharmaceutically acceptable salt thereof and/or a compound of Formula I or a pharmaceutically acceptable salt thereof. In one embodiment, are suitable for ocular injection. The microparticles of the present invention can be administered via intravitreal, intrastromal, intracameral, subtenon, sub-retinal, retrobulbar, peribulbar, suprachoroidal, subchoroidal, conjunctival, subconjunctival, episcleral, posterior juxtascleral, circumcorneal, or tear duct injections. In one embodiment, the microparticles are injected via subchoroidal injection. In one embodiment, the microparticles are injected via subconjunctival injection. In one embodiment, the microparticles are injected via intravitreal injection.

In an alternative embodiment, the microparticles are also suitable for systemic, parenteral, transmembrane, transdermal, buccal, subcutaneous, endosinusial, intra-abdominal, intra-articular, intracartilaginous, intracerebral, intracoronal, dental, intradiscal, intramuscular, intratumor, topical, or vaginal delivery in any manner useful for in vivo delivery.

In one embodiment, the microparticles comprise at least one biodegradable polymer, for example at least one hydrophobic polymer and at least one hydrophobic polymer conjugated to a hydrophilic polymer. In one embodiment, the hydrophobic polymer is poly lactic-co-glycolic acid (PLGA) and/or polylactic acid (PLA). In one embodiment, the hydrophobic polymer conjugated to a hydrophilic polymer is PLGA conjugated to polyalkylene glycol, such as polyethylene glycol (PEG).

In certain embodiments, the microparticles of the present invention have a drug loading of the compound of Formula I or a pharmaceutically acceptable salt thereof of greater than about 42%, 43%, 44%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100% by weight. In certain embodiments, the microparticles have a drug load between about 42% and about 65%, between about 55% and about 75%, between about 65% and about 85%, between about 75% and 95%, or between about 85% and 100% by weight. In an alternative embodiment, the microparticles have a drug load between about 1 and about 15%, between about 15 and about 30%, or between about 30 and about 42% by weight.

In certain embodiments, the microparticles of the present invention have a combined drug loading of timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I or a pharmaceutically acceptable salt thereof of greater than about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100% by weight. In certain embodiments, the microparticles have a combined drug load between about 5% and about 15%, between about 15% and about 30%, between about 30% and 45%, between about 45% and about 65%, between about 55% and about 75%, between about 65% and about 85%, between about 75% and 95%, or between about 85% and 100% by weight. In an alternative embodiment, the microparticles have a drug load between about 1 and about 15%, between about 15 and about 30%, or between about 30 and about 42% by weight.

In one embodiment, the microparticles comprise at least one biodegradable polymer. In certain embodiments, these polymeric microparticles have a drug load of at least or greater than about 42%, 45%, 50%, 60%, 70%, or 80% by weight. In one embodiment, the at least one biodegradable polymer is PLGA and/or PLA and PLGA conjugated to PEG.

In certain embodiments, the microparticles comprise at least one non-active agent, such as an excipient or a non-active agent. In certain embodiments, these microparticles have a drug load of at least or greater than about 42%, 45%, 50%, 60%, 70%, or 80% by weight. In one embodiment, the non-active agent is a sugar, for example mannitol.

In one embodiment, the microparticles comprise at least one biodegradable polymer and at least one non-active agent, such as an excipient or a non-active agent. In certain embodiments, these microparticles have a drug load of at least or greater than about 42%, 45%, 50%, 60%, 70%, or 80% by weight. In one embodiment, the at least one biodegradable polymer is PLGA and/or PLA and PLGA conjugated to PEG. In one embodiment, the non-active agent is a sugar, for example mannitol.

In one embodiment, the microparticles comprise about 100% by weight of the compound of Formula I or a pharmaceutically acceptable salt thereof. In one embodiment, the microparticles comprise about 100% of timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I or a pharmaceutically acceptable salt thereof. In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 5% by weight (with or without salt) to about 95% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 10% by weight (with or without salt) to about 90% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 15% by weight (with or without salt) to about 85% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 20% by weight (with or without salt) to about 80% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 25% by weight (with or without salt) to about 75% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 30% by weight (with or without salt) to about 70% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 35% by weight (with or without salt) to about 65% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 40% by weight (with or without salt) to about 60% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 45% by weight (with or without salt) to about 55% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 50% by weight (with or without salt) to about 50% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 55% by weight (with or without salt) to about 45% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 60% by weight (with or without salt) to about 40% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 65% by weight (with or without salt) to about 35% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 70% by weight (with or without salt) to about 30% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 75% by weight (with or without salt) to about 25% or less (with or without salt) by weight. In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 80% by weight (with or without salt) to about 20% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 85% by weight (with or without salt) to about 15% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 90% by weight (with or without salt) to about 10% or less (with or without salt) by weight.

In certain embodiments, the ratio of a compound of Formula I or a pharmaceutically acceptable salt to timolol or a pharmaceutically acceptable salt in the microparticles of the present invention is selected from up to about 95% by weight (with or without salt) to about 5% or less (with or without salt) by weight.

In one embodiment, the microparticles comprise (a) timolol and a pharmaceutically acceptable salt thereof; (b) timolol; and (c) a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof. In one embodiment, the microparticles comprise up to about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof with the remaining balance being timolol and a pharmaceutically salt thereof, timolol, at least one polymer, and non-active excipients. In one embodiment, the microparticles comprise up to about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, or 95% by weight timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof with the remaining balance being timolol and a pharmaceutically salt thereof, timolol, and non-active excipients.

The microparticles typically have a size in their longest dimension, or their diameter if they are substantially spherical, of more than at least about 1 pm and less than about 100 pm. The microparticles more typically have a size in their longest dimension, or their diameter, of less than about 75 pm. The microparticles, for example, may have a size in their longest dimension, or their diameter, of about 1 or more pm and about 40 or less pm, more typically, between about 20 pm and about 40 mih. Polymer particles of the desired size may, for example, in one embodiment, pass through a sieve or filter with a pore size of about 40 pm. In certain embodiments the microparticle has a mean diameter between about 10 and 60 pm, about 20 and 50 pm, about 20 and 40 pm, about 20 and 30 pm, about 25 and 40 pm, or about 25 and 35 pm.

The microparticles of the present invention provides sustained delivery of timolol or a pharmaceutically acceptable salt thereof and/or a compound of Formula I for at least about one month, or at least about two months, or at least about three months, or at least four months, or at least five months, or at least six months, or at least seven months, or at least eight months, or at least nine months, or at least ten months, or at least eleven months, or at least twelve months. In one embodiment, timolol or a pharmaceutically acceptable salt thereof is timolol maleate.

In one embodiment, the microparticles are mildly surface-treated and upon injection in vivo , aggregate to a microparticle depot in a manner that reduces unwanted side effects of the smaller particles and are suitable for long term (for example, up to or at least three month, up to four month, up to five month, up to six months, up to seven months, up to eight months, up to nine months or longer) sustained delivery of timolol or a pharmaceutically acceptable salt thereof and/or a compound of Formula I or a pharmaceutically acceptable salt thereof.

In one embodiment, the lightly surface treated solid biodegradable microparticles are suitable for ocular injection, at which point the particles aggregate to form a microparticle depot and thus remain outside the visual axis as not to significantly impair vision. The particles can aggregate into one or several pellets or depots. The size of the aggregate depends on the mass (weight) of the particles injected.

The mildly surface treated biodegradable microparticles provided herein are distinguished from “scaffold” microparticles, which are used for tissue regrowth via pores that cells or tissue material can occupy. In contrast, the present microparticles are designed to be solid materials of sufficiently low porosity so that they can aggregate to form a larger combined particle that erodes primarily by surface erosion for long-term controlled drug delivery.

The surface modified solid aggregating microparticles of the present invention are suitable, for example, for intravitreal injection, periocular delivery, or delivery in vivo outside the eye.

In this embodiment, the surface-modified solid aggregating microparticles comprise a compound of Formula I or a pharmaceutically acceptable salt thereof and surfactant wherein the microparticles: a) have a modified surface which has been treated under mild conditions to partially remove surfactant; b) are sufficiently small to be injected in vivo ; c) aggregate in vivo to form at least one aggregated microparticle depot of at least 500 pm in vivo in a manner that provides sustained drug delivery in vivo for at least one month; and d) have a weight loading of about 42% or greater of the compound of Formula I:

or a pharmaceutically acceptable salt thereof; wherein R¹, R², R³, R⁴, x, y, and z are defined herein.

In an alternative embodiment, the surface-modified solid aggregating microparticles further comprise timolol or a pharmaceutically acceptable salt thereof, for example, timolol maleate.

In certain embodiments, the surface-modified microparticles of the present invention have a drug loading of the compound of Formula I or a pharmaceutically acceptable salt thereof of greater than about 42%, 43%, 44%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100% by weight.

In certain embodiments, the surface-modified microparticles comprise both timolol or a pharmaceutically acceptable salt thereof and a timolol prodrug of Formula I or a pharmaceutically acceptable salt thereof and have a combined drug loading of greater than about 5%, 10%, 15%, 20%, 30%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or 100% by weight.

In certain embodiments, the surface-modified microparticles comprise at least one biodegradable polymer, for example at least one hydrophobic polymer and at least one hydrophobic polymer conjugated to a hydrophilic polymer. In one embodiment, the hydrophobic polymer is poly lactic-co-glycolic acid (PLGA) and/or polylactic acid (PLA). In one embodiment, the hydrophobic polymer conjugated to a hydrophilic polymer is PLGA conjugated to polyalkylene glycol, such as polyethylene glycol (PEG).

In one embodiment, the surface-modified microparticles comprise one or more non-active agents, such as an excipient, for example a sugar or a plasticizer. In one embodiment, the sugar is mannitol. In one embodiment, the plasticizer comprises polyethylene glycol.

In certain embodiments, surface-treated aggregating microparticles that encapsulate timolol or a pharmaceutically acceptable salt thereof and/or a compound of Formula I or a pharmaceutically acceptable salt thereof aggregate to a microparticle depot in vivo that exhibits increased hardness and durability. For example, in certain embodiments, the microparticle depot exhibits a hardness rating in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water of at least about 10, and in some embodiments, at least about 15, 20, 30, 40, 50, 60, 70, 75, 100, 120, 150, or more gram-force needed to compress the particle at 30% of strain. In a preferred embodiment, the fluid is vitreous fluid in a human eye.

In certain embodiments, the hardness of the microparticle depot, upon injection in the vitreous, increase at least two-fold, at least three-fold, at least four-fold, at least five-fold, or more in four hours or less following injection compared to microparticles administered immediately after injection (for example, less than one minute or even 30 seconds after administration). In certain embodiments, the hardness increases in about three hours or less, in two hours or less, in one hour or less, in thirty minutes or less, in fifteen minutes or less, in ten minutes or less, in five minutes or less, in two minutes or less, or in one minute or less.

In certain embodiments, the surface-modified microparticles have a drug loading between about 42% and about 65% by weight of a timolol prodrug of Formula I and the microparticles aggregate to a microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10, 20, 40, 50, 60, 70, 75, 100, 120, 150, 170, 200, or more gram-force needed to compress the particle at 30% of strain in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

In certain embodiments, the surface-modified microparticles have a drug loading between about 65% and about 85% by weight of a timolol prodrug of Formula I and the microparticles aggregate to a microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10, 20, 40, 50, 60, 70, 75, 100, 120, 150, 170, 200, or more gram-force needed to compress the particle at 30% of strain.

In certain embodiments, the surface-modified microparticles have a drug loading between about 85% and about 100% by weight of a timolol prodrug of Formula I and the microparticles aggregate to a microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10, 20, 40, 50, 60, 70, 75, 100, 120, 150, 170, 200, or more gram-force needed to compress the particle at 30% of strain.

In certain embodiments, the surface-modified microparticles have a combined drug loading between about 5% and about 30% by weight of timolol or a pharmaceutically acceptable salt thereof and a timolol prodrug of Formula I and the microparticles aggregate to a microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10, 20, 40, 50, 60, 70, 75, 100, 120, 150, 170, 200, or more gram-force needed to compress the particle at 30% of strain in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

In certain embodiments, the surface-modified microparticles have a combined drug loading between about 30% and about 50% by weight of timolol or a pharmaceutically acceptable salt thereof and a timolol prodrug of Formula I and the microparticles aggregate to a microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10, 20, 40, 50, 60, 70, 75, 100, 120, 150, 170, 200, or more gram-force needed to compress the particle at 30% of strain.

In certain embodiments, the surface-modified microparticles have a combined drug loading between about 50% and about 85% by weight of timolol or a pharmaceutically acceptable salt thereof and a timolol prodrug of Formula I and the microparticles aggregate to a microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10, 20, 40, 50, 60, 70, 75, 100, 120, 150, 170, 200, or more gram-force needed to compress the particle at 30% of strain.

In certain embodiments, the surface-modified microparticles have a combined drug loading between about 85% and about 100% by weight of timolol or a pharmaceutically acceptable salt thereof and a timolol prodrug of Formula I and the microparticles aggregate to a microparticle depot in vivo of at least 500 microns that exhibits a hardness rating of at least about 10, 20, 40, 50, 60, 70, 75, 100, 120, 150, 170, 200, or more gram-force needed to compress the particle at 30% of strain.

The surface modified solid aggregating microparticles are suitable, for example, for an intravitreal injection, implant, including an ocular implant, periocular delivery or delivery in vivo outside of the eye. In certain embodiments, microparticles have also been treated for enhanced wettability by subjecting the microparticle suspensions to vacuum or sonication as described herein.

In some embodiments, the surface treatment is carried out at a temperature of not more than about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 °C, at a reduced temperature of about 5 to about 18 °C, about 5 to about 16 °C, about 5 to about 15 °C, about 0 to about 10 °C, about 0 to about 8 °C, or about 1 to about 5 °C, about 5 to about 20 °C, about 1 to about 10 °C, about 0 to about 15 °C, about 0 to about 10 °C, about 1 to about 8 °C, or about 1 to about 5 °C. Each combination of each of these conditions is considered independently disclosed as if each combination were separately listed. Alternatively, the surface treatment is conducted at a temperature at or less than about 10 °C, 8 °C or 5 °C. The decreased temperature of processing (less than room temperature, and typically less than 18 °C) assists to ensure that the particles are only “mildly” surface treated.

In certain embodiments, the surface treatment includes treating microparticles with a surface-treatment agent comprising a base, for example, sodium hydroxide or potassium hydroxide, and an organic solvent (such as an alcohol, for example ethanol or methanol, or an organic solvent such as DMF, DMSO or ethyl acetate) as otherwise described herein.

Additional non-limiting examples of a base for the surface-treatment include lithium hydroxide, calcium hydroxide, magnesium hydroxide, lithium amide, sodium amide, barium carbonate, barium hydroxide, barium hydroxide hydrate, calcium carbonate, cesium carbonate, cesium hydroxide, lithium carbonate, magnesium carbonate, potassium carbonate, sodium carbonate, strontium carbonate, ammonia, methylamine, ethylamine, propylamine, isopropylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, aniline, methylaniline, dimethylaniline, pyridine, azajulolidine, benzylamine, methylbenzylamine, dimethylbenzylamine, DABCO, 1,5- diazabicyclo[4.3.0]non-5-ene, l,8-diazabicyclo[5.4.0]non-7-ene, 2,6-lutidine, morpholine, piperidine, piperazine, Proton-sponge, l,5,7-Triazabicyclo[4.4.0]dec-5-ene, tripelennamine, ammonium hydroxide, triethanolamine, ethanolamine, and Trizma.

Additional non-limiting examples of an organic solvent for the surface-treatment include ether, acetone, acetonitrile, THF, dimethylacetamide, carbon disulfide, chloroform, 1,1- dichloroethane, di chi orom ethane, heptane, hexane, methanol, methyl acetate, methyl /-butyl ether (MTBE), pentane, propanol, 2-propanol, toluene, A^f-m ethyl pyrrolidinone (NMP), acetamide, piperazine, triethylenediamine, diols, and CO2 .

When carrying out the treatment in base, the pH may, for example, range from about 7.0 or 7.5 to about 14, including not more than about 8, 9, 10, 11, 12, 13 or 14. In one embodiment, the surface-treatment can be conducted in a pH between about 7.5 and 8.5. In one embodiment, the surface treatment can be conducted at a pH between about 8 and about 10. In one embodiment, the surface treatment can be conducted at a pH between about 10.0 and about 13.0. In one embodiment, the surface treatment can be conducted at a pH between about 10.0 and about 12.0. In one embodiment, the surface treatment can be conducted at a pH between about 12 and about 14.

Non-limiting examples of surface-treatment conditions include ethanol with an aqueous organic base; ethanol and aqueous inorganic base; ethanol and sodium hydroxide; and ethanol and potassium hydroxide.

In an alternative embodiment, the surface treatment includes treating microparticles under acidic or neutral conditions, for example at a pH ranging from about 7.5 to about 1, including not more than 1, 2, 3, 4, 5, 6, or 7. When carrying out the treatment in acid, the pH may range from about 6.5 to about 1, including not less than 1, 2, 3, 4, 5, 6, 7, or 8. When carrying out under neutral conditions, the pH may typically range from about 6.4 or 6.5 to about 7.4 or 7.5.

In certain embodiments, the surface treatment as described above is carried out in an inorganic acid including, but not limited to, hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like; or organic acids including, but not limited to, acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, mesylic, esylic, besylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, HOOC-(CH2)_n- COOH where n is 0-4, and the like. Each combination of each of these conditions described herein is considered independently disclosed as if each combination were separately listed.

The treatment conditions should simply mildly treat the surface in a manner that allows the particles to remain as solid particles, be injectable without undue aggregation or clumping, and form at least one aggregate particle of at least 500 pm. In one embodiment, the treatment partially removes the surface surfactant.

In certain embodiments, the surface treatment includes treating microparticles with an organic solvent at a reduced temperature of about 0 to about 18 °C, about 0 to about 16 °C, about 0 to about 15 °C, about 0 to about 10 °C, about 0 to about 8 °C, or about 0 to about 5 °C. In certain embodiments, the organic solvent is ethanol.

In certain embodiments, the surface treatment includes treating microparticles with an aqueous solution of pH = 6.6 to 7.4 or 7.5 and an organic solvent at a reduced temperature of about 0 to about 18 °C, about 5 to about 15 °C, or about 7 to about 13 °C. In one embodiment, the organic solvent is ethanol.

In certain embodiments, the surface treatment includes treating microparticles with an base at a concentration between about 2.5 mM and about 12 mM and an organic solvent at a reduced temperature of about 0 to about 18 °C, about 5 to about 15 °C, or about 7 to about 13 °C. In one embodiment, the organic solvent is ethanol. In one embodiment, the base is NaOH. In certain embodiments, the base concentration is between about 2.5 mM and about 10 mM, between about 2 mM and about 4 mM, between about 4 mM and 8 mM, or between about 5 mM and 7.5 mM. In certain embodiments, the base concentration is about 2.5 mM, about 5.0 mM, about 7.5 mM, or about 10 mM. In certain embodiments, the organic solvent concentration in the base/organic solvent solution is between about 10% and about 80%, between about 20% and about 70%, between about 30% and about 60%, between about 40% and about 55%, or between about 45% and about 50%. In certain embodiments, the concentration is at least about 10%, at least about 20%, at least about 30%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, or at least about 70%. In one embodiment, the organic solvent is an alcohol, for example ethanol.

In certain embodiments, the surface treatment conditions include treating a microparticle with 2.5 mM NaOH/ethanol wherein the solution is approximately 90:10, 30:70, 45:55, 55:45, 60:40, 65:35, 70:20, or 75: 25, v:v. In certain embodiments, the surface treatment conditions include treating a microparticle with 5.0 mM NaOH/ethanol wherein the solution is approximately 90:10, 30:70, 45:55, 55:45, 60:40, 65:35, 70:20, or 75: 25, v:v.

In certain embodiments, the surface treatment conditions include treating a microparticle with 7.5 mM NaOH/ethanol wherein the solution is approximately 90:10, 30:70, 45:55, 55:45, 60:40, 65:35, 70:20, or 75: 25, v:v.

In certain embodiments, the surface treatment conditions include treating a microparticle with 10 mM NaOH/ethanol wherein the solution is approximately 90:10, 30:70, 45:55, 55:45, 60:40, 65:35, 70:20, or 75: 25, v:v.

In certain embodiments, the microparticles have a mean size of about 20 pm to about 50 pm, 25 pm to about 45 pm, 25 pm to about 30 pm, or 30 to 33 pm and a median size of about 31 pm to about 33 pm after surface treatment with approximately 2.0 mM NaOH/ethanol to 8.0 mM NaOH/ethanol (approximately 30:70, v:v).

In certain embodiments, the microparticles have a mean size of about 20 pm to about 50 pm, 25 pm to about 45 pm, 25 pm to about 30 pm or 30 to 33 pm and a median size of about 31 pm to about 33 pm after surface treatment with approximately 2.0 mM NaOH/ethanol to 8.0 mM NaOH/ethanol (approximately 50:50, v:v).

In certain embodiments, the microparticles have a mean size of about 20 pm to about 50 pm, about 25 pm to about 45 pm, about 25 pm to about 30 pm or 30 to 33 pm and a median size of about 31 pm to about 33 pm after surface treatment with approximately 2.0 mM NaOH/ethanol to 8.0 mM NaOH/ethanol (approximately 70:30, v:v).

In certain embodiments, the microparticles have a drug loading between about 45% and about 60% and are surface treated with approximately 2.0 mM NaOH/ethanol to 6.0 mM NaOH/ethanol where the concentration of ethanol in the solution is between about 50% and 60% by volume. In one embodiment, the microparticles with a drug loading of about 45% are surface- treated with approximately 5.0 mM NaOH/EtOH (45:55, v/v). In one embodiment, the microparticles with a drug loading of about 45% are surface-treated with approximately 2.5 mM NaOH/EtOH (45:55 or 50:50, v/v).

In one embodiment, the microparticles have a drug loading of 100% and are surface treated with approximately 2.0 mM NaOH/ethanol to 6.0 mM NaOH/ethanol where the concentration of ethanol in the solution is between about 20% and 40% by volume. In one embodiment, the microparticles with a drug loading of 100% are surface-treated with approximately 2.5 mM NaOH/EtOH (70:30, v/v).

In order for the surface treated microparticles to form a consolidated aggregate, the temperature around the particles, for example in the human or non-human animal where the composition is administered, is approximately equal to, or greater than, the glass transition temperature (T_g) of the polymer particles. At such temperatures the polymer particles will cross link to one or more other polymer particles to form a consolidated aggregate. By cross-link it is meant that adjacent polymer particles become joined together. For example, the particles may cross-link due to entanglement of the polymer chains at the surface of one particle with polymer chains at the surface of another particle. There may be adhesion, cohesion or fusion between adjacent particles.

Where more than one type of polymer is used, each surface treated microparticle may have a different solidifying or setting property. For example, the surface treated microparticles may be made from similar polymers but may have different gelling pHs or different melting temperatures or glass transition points. Typically, the injectable surface treated microparticles which are formed of a polymer or a polymer blend have a glass transition temperature (T_g) either close to or just above body temperature (such as from about 30 °C to 45 °C, e.g., from about 35 °C to 40 °C, for example, from about 37 °C to 40 °C). Accordingly, at room temperature the surface treated microparticles are below their T_g and behave as discrete particles, but in the body the surface treated microparticles soften and interact/stick to themselves. Typically, agglomeration begins within 20 seconds to about 15 minutes of the raise in temperature from room to body temperature.

The surface treated microparticles may be formed from a polymer which has a T_g from about 35 °C to 40 °C, for example from about 37 °C to 40 °C, wherein the polymer is a poly(a- hydroxyacid) (such as PLA, PGA, PLGA, or PDLLA or a combination thereof), or a blend thereof with PLGA-PEG. Typically, these particles will agglomerate at body temperature. The injectable surface treated microparticles may comprise only poly(a-hydroxyacid) particles or other particle types may be included. The microparticles can be formed from a blend of poly(D,L-lactide-co- glycolide)(PLGA), PLGA-PEG and PVA which has a T_g at or above body temperature. In one embodiment, at body temperature the surface treated microparticles will interact to form a consolidated aggregate. The injectable microparticle may comprise only PLGA/PLGA-PEG/PVA surface treated microparticles or other particle types may be included. The composition may comprise a mixture of temperature sensitive surface treated microparticles and non-temperature sensitive surface treated microparticles. Non-temperature sensitive surface treated microparticles are particles with a glass transition temperature which is above the temperature at which the composition is intended to be used. Typically, in a composition comprising a mixture of temperature sensitive surface treated microparticles and non-temperature sensitive particles the ratio of temperature sensitive to non-temperature sensitive surface treated microparticles is about 3:1, or lower, for example, 4:3. The temperature sensitive surface treated microparticles are advantageously capable of crosslinking to each other when the temperature of the composition is raised to or above the glass transition of these microparticles. By controlling the ratio of temperature sensitive surface treated microparticles to non-temperature sensitive surface treated microparticles it may be possible to manipulate the porosity of the resulting consolidated aggregate. The surface treated microparticles may be solid, that is with a solid outer surface, or they may be porous. The particles may be irregular or substantially spherical in shape.

In certain embodiments, the microparticles have a mean size of about 25 pm to about 50 pm, 25 pm to about 45 pm, 25 pm to about 30 pm and a median size of about 29 pm to about 31 pm before surface treatment.

Further, in various embodiments, the surface-modified solid aggregating microparticles of the disclosed invention can aggregate to produce at least one depot when administered in vivo that has a diameter of at least about 300 pm, 400 pm, 500 pm, 600 pm, 700 pm, 1 mm, 1.5 mm, 2 mm, 3 mm, 4 mm, or 5 mm.

Formation of the consolidated aggregate from the composition, once administered to a human or non-human animal, typically takes from about 20 seconds to about 24 hours, for example, between about 1 minute and about 5 hours, between about 1 minute and about 1 hour, less than about 30 minutes, less than about 20 minutes. Typically, the solidification occurs in between about 1 minute and about 20 minutes from administration.

In certain embodiments, the surface-modified solid aggregating microparticles of the present invention produce a microparticle depot in vivo that releases the therapeutic agent without a burst of more than about 10 percent or 15 percent of the total payload of the therapeutic agent over a one week, or a five, four, three, two day or one day period.

In some embodiments, the long-term controlled drug delivery is accomplished by a combination of surface erosion of an aggregated microparticle depot over several months (for example, one, two, three, or four months or more) followed by erosion of remaining parts of the aggregated microparticle depot, followed by slow release of active material from in vivo proteins to which it has bound over the period of long term release from the aggregated particle. In another embodiment, the microparticle degrades substantially by surface erosion over a period of at least about one, two, three, four, five or six months or more.

In one embodiment, the agent that removes surface surfactant is not a degrading agent of the biodegradable polymer under the conditions of the reaction. The hydrophilicity of the microparticles can be decreased by removing surfactant. In one embodiment, the surface-treated microparticles contain less surfactant than a microparticle prior to the surface modification. In one embodiment, the surface-treated microparticles contain from about 0.001 percent to about 1 percent surfactant following surface-treatment.

In one embodiment, the surface-modified solid aggregating microparticles are more hydrophobic than the microparticles prior to the surface modification.

In an alternative embodiment, the weight percent of surface-modified solid aggregating microparticles that are not aggregated into a larger depot in vivo is about 10 percent or less, 7 percent or less, 5 percent or less, or 2 percent or less by total weight administered.

In one embodiment, the surface-modified solid aggregating microparticles do not cause substantial inflammation in the eye.

In another embodiment, the surface-modified solid aggregating microparticles do not cause an immune response in the eye.

In one embodiment, the microparticles after surface treatment have about the same mean size and median size. In another embodiment, the microparticles after surface treatment have a mean size which is larger than the median size. In another embodiment, the microparticles after surface treatment have a mean size which is smaller than the median size.

In one embodiment, a surface-modified solid aggregating microparticle is manufactured using a wet microparticle.

In one embodiment, a surface-modified solid aggregating microparticle is less inflammatory than a non-surface treated microparticle.

In one embodiment, the agent that removes the surface surfactant of a surface-modified solid aggregating microparticle comprises a solvent that partially dissolves or swells the surface- modified solid aggregating microparticle. In one embodiment, the surface-modified solid aggregating microparticles are capable of releasing a compound of Formula I over a longer period of time compared to a non-surface treated microparticle.

In one embodiment, a microparticle comprising a compound of Formula I allows a substantially zero or first order release rate of the compound of Formula I from the consolidated aggregate once the consolidated aggregate has formed. A zero order release rate is a constant release of the compound of Formula I over a defined time; such release is difficult to achieve using known delivery methods.

In one embodiment, the microparticles of the present invention have a solid core. In certain embodiments, the solid core is less than 10 percent porosity, 8 percent porosity, 7 percent porosity, 6 percent porosity, 5 percent porosity, 4 percent porosity, 3 percent porosity, or 2 percent porosity. Porosity as used herein is defined by ratio of void space to total volume of the surface-modified solid aggregating microparticle.

The encapsulation efficiency of the process of manufacturing microparticles depends on the microparticle forming conditions and the properties of the therapeutic agent. In certain embodiments, the encapsulation efficiency can be greater than about 50 percent, greater than about 75 percent, greater than about 80 percent, or greater than about 90 percent.

In certain embodiments, the solid biodegradable microparticles release about 1 to about 20 percent, about 1 to about 15 percent, about 1 to about 10 percent, or about 5 to 20 percent, for example, up to about 1, 5, 10, 15 or 20 percent, of the therapeutic agent over the first twenty-four- hour period.

In one embodiment, the microparticles have only residual solvents that are pharmaceutically acceptable.

In one embodiment, the microparticles afford a total release of greater than eighty percent by day 14.

In certain embodiments, the microparticles have syringeability with a regular-walled 26-, 27-, 28-, 29- or 30-gauge needle of 200 mg/ml with no clogging of the syringe.

In certain embodiments, the microparticles have syringeability with a thin-walled 26-, 27- , 28-, 29- or 30-gauge needle of 200 mg/ml with no clogging of the syringe.

In one embodiment, the microparticles have an endotoxin level of less than 0.02 EU/mg.

In one embodiment, the microparticles have a bioburden level of less than 10 CFU/g. In one embodiment, the microparticles are suspended in a diluent of 10X Pro Vi sc-diluted (0.1% HA in PBS) solution comprising additive that improves particle aggregation. In one embodiment, the microparticles are suspended in a diluent of 20X-diluted Pro Vise (0.05% HA in PBS) comprising additive that improves particle aggregation. In one embodiment, the microparticles are suspended in a diluent of 40X-diluted Pro Vise (0.025% HA in PBS) comprising additive that improves particle aggregation.

Non-limiting examples of additives include triethyl citrate, benzyl alcohol, polyethylene glycol, N-methyl-2-pyrrolidone (NMP), 2-pyrrolidone, DMSO, triacetin, benzyl acetate, benzyl benzoate, acetyltributyl citrate, dibutyl sebacate, dimethylphthalate, tributyl O-acetylcitrate, ethanol, methanol, polysorbate 80, ethyl acetate, propylene carbonate, isopropyl acetate, methyl acetate, methyl ethyl ketone, butyl lactate, and isovaleric acid.

In one embodiment, the microparticles are suspended in a diluent of 10X Pro Vise-diluted (0.1% HA in PBS) solution comprising benzyl alcohol. In one embodiment, the microparticles are suspended in a diluent of 20X-diluted Pro Vise (0.05% HA in PBS) comprising benzyl alcohol. In one embodiment, the microparticles are suspended in a diluent of 40X-diluted Pro Vise (0.025% HA in PBS) comprising benzyl alcohol.

In one embodiment, the microparticles are suspended in a diluent of 10X Pro Vise-diluted (0.1% HA in PBS) solution comprising triethyl citrate. In one embodiment, the microparticles are suspended in a diluent of 20X-diluted Pro Vise (0.05% HA in PBS) comprising triethyl citrate. In one embodiment, the microparticles are suspended in a diluent of 40X-diluted Pro Vise (0.025% HA in PBS) comprising triethyl citrate.

In one embodiment, the particles are suspended in the diluent comprising additive that improves particle aggregation at a concentration of 100 mg/mL, 150 mg/mL, 200 mg/mL, 250 mg/mL, 300 mg/mL, 350 mg/mL, 400 mg/mL, 450 mg/mL or 500 mg/mL. In one embodiment, the particles are suspended in 10X-diluted Pro Vise (0.1% HA in PBS) solution comprising additive that improves particle aggregation, and the suspension has a final concentration of 200 mg/mL. In one embodiment, the particles are suspended in 10X-diluted Pro Vise (0.1% HA in PBS) solution comprising additive that improves particle aggregation, and the suspension has a final concentration of 400 mg/mL. In one embodiment, the particles are suspended in a 20X-diluted Pro Vise (0.05% HA in PBS) solution comprising additive that improves particle aggregation, and the suspension has a final concentration of 200 mg/mL. In one embodiment, the particles are suspended in a 20X-diluted ProVisc (0.05% HA in PBS) solution comprising additive that improves particle aggregation, and the suspension has a final concentration of 400 mg/mL. In one embodiment, the particles are suspended in a 40X-diluted ProVisc (0.025% HA in PBS) solution comprising additive that improves particle aggregation, and the suspension has a concentration of 200 mg/mL. In one embodiment, the particles are suspended in a 40X-diluted ProVisc (0.025% HA in PBS) solution comprising additive that improves particle aggregation, and the suspension has a concentration of 400 mg/mL.

In certain embodiments, the diluent for suspending particles is ProVisc comprising additive that improves particle aggregation. In one embodiment, the diluent for suspending particles is sodium hyaluronate comprising additive that improves particle aggregation. In some embodiments, the microparticles are diluted from about 10-fold to about 40-fold, from about 15- fold to about 35-fold, or from about 20-fold to about 25-fold. In some embodiments, the diluent for suspending particles is a 10X-diluted ProVisc (0.1% HA in PBS) solution, a 20X-diluted ProVisc (0.05% HA in PBS) solution, or a 40X-diluted ProVisc (0.025% HA in PBS) solution comprising additive. In some embodiment, the particles are suspended in the diluent comprising additive at a concentration of at least about 100 mg/mL, 200 mg/mL, 300 mg/mL, 400 mg/mL, or 500 mg/mL. In further embodiments, the additive is benzyl alcohol. In further embodiments, the additive is triethyl citrate. In some embodiments, the diluent comprises more than one additive, for example benzyl alcohol and triethyl citrate.

In one embodiment, the additive is benzyl alcohol. In one embodiment, the additive is triethyl citrate. In one embodiment, the additive is selected from polyethylene glycol, N-methyl- 2-pyrrolidone (NMP), 2-pyrrolidone, and DMSO. In one embodiment, the additive is selected from triacetin, benzyl acetate, benzyl benzoate, and acetyltributyl citrate. In one embodiment, the additive is selected from dibutyl sebacate, dimethylphthalate, tributyl O -acetyl citrate, ethanol, and methanol. In one embodiment, the additive is selected from polysorbate 80, ethyl acetate, propylene carbonate, and isopropyl acetate. In one embodiment, the additive is selected from methyl acetate, methyl ethyl ketone, butyl lactate, and isovaleric acid.

In certain embodiments, the diluent contains approximately from about 0.01% to about 10% by weight of additive, from about 0.01% to about 0.1% by weight of additive, from about 0.05% to about 0.5% by weight of additive, from about 0.1% to about 1.0% by weight of additive, from about 0.1% to about 10% by weight of additive, from about 0.5% to about 5% by weight of additive, from about 0.5% to about 4% by weight of additive, from about 0.5% to about 3% by weight of additive, from about 0.5% to about 2.0% by weight of additive, from about 0.1% to about 0.5% by weight of additive, from about 0.1% to about 0.25% by weight of additive, from about 0.2% to about 2% by weight of additive, or from about 0.01% to about 0.05% by weight of additive.

The diluent is present in an amount in a range of from about 0.5 weight percent to about 95 weight percent of the drug delivery particles. The diluent can also be an aqueous diluent. Examples of aqueous diluent include, but are not limited to, an aqueous solution or suspension, such as saline, plasma, bone marrow aspirate, buffers, such as Hank's Buffered Salt Solution (HBSS), HEPES (4-(2-hydroxyethyl)-l-piperazineethanesulfonic acid), Ringers buffer, Pro Vise®, diluted Pro Vise®, Pro Vise® diluted with PBS, Krebs buffer, Dulbecco's PBS, normal PBS; sodium hyaluronate solution (HA, 5 mg/mL in PBS), simulated body fluids, plasma platelet concentrate and tissue culture medium or an aqueous solution or suspension comprising an organic solvent. Pro Vise® is a sterile, non-pyrogenic, high molecular weight, non-inflammatory highly purified fraction of sodium hyaluronate, dissolved in physiological sodium chloride phosphate buffer.

In one embodiment, the diluent is PBS.

In one embodiment, the diluent is HA, 5 mg/mL in PBS.

In one embodiment, the diluent is Pro Vise® diluted with water.

In one embodiment, the diluent is Pro Vise® dilution in PBS.

In one embodiment, the diluent is Pro Vise® 5-fold diluted with water.

In one embodiment, the diluent is Pro Vise® 5-fold dilution in PBS.

In one embodiment, the diluent is Pro Vise® 10-fold diluted with water.

In one embodiment, the diluent is Pro Vise® 10-fold dilution in PBS.

In one embodiment, the diluent is Pro Vise® 20-fold dilution with water.

In one embodiment, the diluent is Pro Vise® 20-fold dilution in PBS.

In one embodiment, the diluent is HA, 1.25 mg/mL in an isotonic buffer solution with neutral pH.

In one embodiment, the diluent is HA, 0.625 mg/mL in an isotonic buffer solution with neutral pH.

In one embodiment, the diluent is HA, 0.1-5.0 mg/mL in PBS. In one embodiment, the diluent is HA, 0.5-4.5 mg/mL in PBS. In one embodiment, the diluent is HA, 1.0-4.0 mg/mL in PBS. In one embodiment, the diluent is HA, 1.5-3.5 mg/mL in PBS. In one embodiment, the diluent is HA, 2.0-3.0 mg/mL in PBS. In one embodiment, the diluent is HA, 2.5-3.0 mg/mL in PBS.

IV. Compounds of Formula I

The compositions of the present invention for ocular delivery comprise a prodrug of Formula I:

or a pharmaceutically acceptable salt thereof; wherein:

R¹ and R² are independently selected from (i) hydrogen and -C(0)R³;

wherein R¹ and R² cannot both be hydrogen;

R³ is independently selected from H, alkyl, cycloalkyl, cycloalkylalkyl, heterocycle, heterocycloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, aryloxy, and alkyloxy;

R⁴ is independently selected from hydrogen, -C(0)R³, aryl, alkyl, cycloalkyl, cycloalkylalkyl, heterocyclyl, heterocycloalkyl, arylalkyl, heteroaryl, and heteroarylalkyl; x and y are integers independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20; z is an integer independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

The prodrugs of Formula I are prodrugs of the beta-adrenergic antagonist timolol:

Timolol as used in Formula I has (S)-stereochemistry as used in the commercial Timolol maleate ophthalmic solutions, such as Isatol® and Timoptic®. In any of the compounds of Formula I, if the stereochemistry of the chiral carbon is not specifically designated, it is intended that the carbon can be used as an R enantiomer, an S enantiomer, or a mixture of enantiomers include a racemic mixture. For example, moieties that have repetitive units, for example including but not limited to an oligomer of polylactic acid, polypropylene oxide, and polylactide-coglycolide that has a chiral carbon can be used with the chiral carbons all having the same stereochemistry, random stereochemistry, or ordered but different stereochemistry such as a block of S enantiomer units followed by a block of R enantiomer units in each oligomeric unit. In some embodiments lactic acid is used in its naturally occurring S enantiomeric form.

Certain prodrugs of Formula I have been described in U.S. Application US 2020/0031783. Aggregating microparticles for ocular therapy that encapsulate certain prodrugs of Formula I are described in U.S. Application No. US 2018-0326078 and US 2020-023-246, and PCT Application WO 2020/102758. Syntheses of certain prodrugs of Formula I are described in US 2020/0031783.

For example, in one embodiment, R¹ and R² are independently selected from

In one embodiment, R¹ and R² are independently selected from

wherein x and y are independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In one embodiment, R¹ and R² are independently selected from

In one embodiment, R¹ and R² are independently selected from

In one embodiment, R¹ and R² are independently selected from

In one embodiment, R¹ and R² are independently selected from

In one embodiment, R¹ and R² are independently selected from

In one embodiment, R¹ and R² are independently selected from

In one embodiment, R¹ is hydrogen and R² is selected from

wherein x and y are independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In one embodiment, R¹ is -C(0)R³ and R² is selected from

wherein R³ is alkyl and x and y are independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, or

10 In one embodiment, x and y are independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

In one embodiment, x and y are independently selected from 1, 2, 3, 4, 5, or 6. In one embodiment, x and y are independently selected from 1, 2, or 3. In one embodiment, x is 1 and y is 1. In one embodiment, x is 1 and y is 2. In one embodiment, x is 1 and y is 3. In one embodiment, x is 1 and y is 4. In one embodiment, x is 1 and y is 5. In one embodiment, x is 1 and y is 6. In one embodiment, x is 1 and y is 7. In one embodiment, x is 1 and y is 8. In one embodiment, x is 1 and y is 9. In one embodiment, x is 1 and y is 10. In one embodiment, x is 2 and y is 1. In one embodiment, x is 2 and y is 2. In one embodiment, x is 2 and y is 3. In one embodiment, x is 2 and y is 4. In one embodiment, x is 2 and y is 5. In one embodiment, x is 2 and y is 6. In one embodiment, x is 2 and y is 7. In one embodiment, x is 2 and y is 8. In one embodiment, x is 2 and y is 9. In one embodiment, x is 2 and y is 10. In one embodiment, x is 3 and y is 1. In one embodiment, x is 3 and y is 2. In one embodiment, x is 3 and y is 3. In one embodiment, x is 3 and y is 4. In one embodiment, x is 3 and y is 5. In one embodiment, x is 3 and y is 6. In one embodiment, x is 3 and y is 7. In one embodiment, x is 3 and y is 8. In one embodiment, x is 3 and y is 9. In one embodiment, x is 3 and y is 10. In one embodiment, x is 4 and y is 1. In one embodiment, x is 4 and y is 2. In one embodiment, x is 4 and y is 3. In one embodiment, x is 4 and y is 4. In one embodiment, x is 4 and y is 5. In one embodiment, x is 4 and y is 6. In one embodiment, x is 4 and y is 7. In one embodiment, x is 4 and y is 8. In one embodiment, x is 4 and y is 9. In one embodiment, x is 4 and y is 10. In one embodiment, x is 5 and y is 1. In one embodiment, x is 5 and y is 2. In one embodiment, x is 5 and y is 3. In one embodiment, x is 5 and y is 4. In one embodiment, x is 5 and y is 5. In one embodiment, x is 5 and y is 6. In one embodiment, x is 5 and y is 7. In one embodiment, x is 5 and y is 8. In one embodiment, x is 5 and y is 9. In one embodiment, x is 5 and y is 10. In one embodiment, x is 6 and y is 1. In one embodiment, x is 6 and y is 2. In one embodiment, x is 6 and y is 3. In one embodiment, x is 6 and y is 4. In one embodiment, x is 6 and y is 5. In one embodiment, x is 6 and y is 6. In one embodiment, x is 6 and y is 7. In one embodiment, x is 6 and y is 8. In one embodiment, x is 6 and y is 9. In one embodiment, x is 6 and y is 10. In one embodiment, x is 7 and y is 1. In one embodiment, x is 7 and y is 2. In one embodiment, x is 7 and y is 3. In one embodiment, x is 7 and y is 4. In one embodiment, x is 7 and y is 5. In one embodiment, x is 7 and y is 6. In one embodiment, x is 7 and y is 7. In one embodiment, x is 7 and y is 8. In one embodiment, x is 7 and y is 9. In one embodiment, x is 7 and y is 10. In one embodiment, x is 8 and y is 1. In one embodiment, x is 8 and y is 2. In one embodiment, x is 8 and y is 3. In one embodiment, x is 8 and y is 4. In one embodiment, x is 8 and y is 5. In one embodiment, x is 8 and y is 6. In one embodiment, x is 8 and y is 7. In one embodiment, x is 8 and y is 8. In one embodiment, x is 8 and y is 9. In one embodiment, x is 8 and y is 10. In one embodiment, x is 9 and y is 1. In one embodiment, x is 9 and y is 2. In one embodiment, x is 9 and y is 3. In one embodiment, x is 9 and y is 4. In one embodiment, x is 9 and y is 5. In one embodiment, x is 9 and y is 6. In one embodiment, x is 9 and y is 7. In one embodiment, x is 9 and y is 8. In one embodiment, x is 9 and y is 9. In one embodiment, x is 9 and y is 10. In one embodiment, x is 10 and y is 1. In one embodiment, x is 10 and y is 2. In one embodiment, x is 10 and y is 3. In one embodiment, x is 10 and y is 4. In one embodiment, x is 10 and y is 5. In one embodiment, x is 10 and y is 6. In one embodiment, x is 10 and y is 7. In one embodiment, x is 10 and y is 8. In one embodiment, x is 10 and y is 9. In one embodiment, x is 10 and y is 10.

Non-limiting examples of a compound of Formula I include:

Non-limiting examples of a compound of Formula I include:

Non-limiting examples of a compound of Formula I include:

In one embodiment, the compound of Formula I is selected from:

In one embodiment, the compound of Formula I is selected from:

In an alternative embodiment, the microparticles or the implant of the present invention for ocular delivery comprise timolol or a pharmaceutically acceptable salt thereof. In one embodiment, timolol or a pharmaceutically acceptable salt thereof is timolol maleate.

V. Biodegradable Polymers

In one embodiment, the formulations of the present invention that encapsulate timolol or a pharmaceutically acceptable salt thereof and/or a compound of Formula I or a pharmaceutically acceptable salt thereof include one or more biodegradable polymers or copolymers. These polymers should be biocompatible in that they can be administered to a patient without an unacceptable adverse effect. Biodegradable polymers are well known to those in the art and are the subject of extensive literature and patents. The biodegradable polymer or combination of polymers can be selected to provide the target characteristics of the microparticles, including the appropriate mix of hydrophobic and hydrophilic qualities, half-life and degradation kinetics in vivo , compatibility with the therapeutic agent to be delivered, appropriate behavior at the site of injection, etc.

In one embodiment, the implant or the microparticles of the present invention include poly(lactic-co-glycolic acid) (PLGA). In another embodiment, the implant or microparticles include a polymer or copolymer that has at least PLGA and PLGA-polyethylene glycol (PEG) (referred to as PLGA-PEG). In one embodiment, the implant or the microparticle includes poly(lactic acid) (PLA). In another embodiment, the implant or the microparticles include a polymer or copolymer that has at least PLA and PLA-polyethylene glycol (PEG) (referred to as PLA-PEG). In another embodiment, the implant or the microparticles include at least PLGA, PLGA-PEG and polyvinyl alcohol (PVA). In another embodiment, the implant or the microparticles include at least PLA, PLA-PEG and polyvinyl alcohol (PVA). Each combination of each of these conditions is considered independently disclosed as if each were separately listed.

In one embodiment, implant or the microparticles comprise (a) PLGA and/or PLGA and (b) a hydrophobic polymer covalently bound to a hydrophilic biodegradable polymer. The PLA and/or PLGA, for example, comprises at least about 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 99.9% of the microparticle. In one embodiment, the PLA and/or PLGA has a molecular weight between about 30 and 60 kD, about 35 and 55kD, or about 40 and 50kD. The implant or microparticle further includes a hydrophobic polymer covalently bound to a hydrophilic biodegradable polymer. Hydrophobic degradable polymers are known in the art, and include, but are not limited to, polyglycolic acid (PGA), poly(D,L-lactide-co-glycolide)(PLGA), and poly D,L-lactic acid (PDLLA); polycaprolactone; polyanhydrides, such as polysebacic anhydride, poly(maleic anhydride); and copolymers thereof. Hydrophilic polymers are known in the art and include, for example poly(alkylene glycols) such as polyethylene glycol (PEG), polyethylene oxide (PEO), and polyethylene glycol) amine; polysaccharides; poly(vinyl alcohol) (PVA); polypyrrolidone; polyacrylamide (PAM); polyethylenimine (PEI); poly(acrylic acid); poly(vinylpyrolidone) (PVP); or a copolymer thereof. Hydrophobic polymers covalently bound to hydrophilic polymers include, for example, PLGA- PEG, PLA-PEG, PCL-PEG in an amount from about 0.5 percent to about 10 percent, about 0.5 percent to about 5 percent, about 0.5 percent to about 4 percent, about 0.5 percent to about 3 percent, or about 0.1 percent to about 1, 2, 5, or 10 percent. In one embodiment, the hydrophobic polymer covalently bound to the hydrophilic polymer is PLGA-PEG.

In one embodiment, the microparticle includes PLGA.

In one embodiment, the microparticle includes PLA.

In one embodiment, the microparticle includes a copolymer of PLGA and PEG.

In one embodiment, the microparticle includes a copolymer of PLA and PEG.

In one embodiment, the microparticle includes PLGA and PLGA-PEG.

In one embodiment, the microparticle includes PLA and PLGA-PEG.

In one embodiment, the microparticle includes PLA and PLA-PEG.

In one embodiment, the microparticle includes PLGA and PLA-PEG.

In one embodiment, the microparticle includes PLGA, PLGA-PEG and PVA.

In one embodiment, the microparticle includes PLA, PLGA-PEG and PVA.

In one embodiment, the microparticle includes PLGA, PLA, and PLGA-PEG.

In one embodiment, the microparticle includes PLGA, PLA, PLGA-PEG and PVA.

In one embodiment, the microparticle comprises PLGA and PLGA-PEG, and combinations thereof.

In one embodiment, the microparticle includes PVA.

In one embodiment, the microparticles include PLGA, PLGA-PEG, PVA, or combinations thereof. In one embodiment, the microparticles include the biocompatible polymers PLA, PLA- PEG, PVA, or combinations thereof.

In one embodiment, the implant includes PLGA.

In one embodiment, the implant includes PLA.

In one embodiment, the implant includes a copolymer of PLGA and PEG.

In one embodiment, the implant includes a copolymer of PLA and PEG.

In one embodiment, the implant includes PLGA and PLGA-PEG.

In one embodiment, the implant includes PLA and PLGA-PEG.

In one embodiment, the implant includes PLA and PLA-PEG.

In one embodiment, the implant includes PLGA and PLA-PEG.

In one embodiment, the implant includes PLGA, PLGA-PEG and PVA.

In one embodiment, the implant includes PLA, PLGA-PEG and PVA.

In one embodiment, the implant includes PLGA, PLA, and PLGA-PEG.

In one embodiment, the implant includes PLGA, PLA, PLGA-PEG and PVA.

In one embodiment, the implant comprises PLGA and PLGA-PEG, and combinations thereof.

In one embodiment, the implant includes PVA.

In one embodiment, the implant includes PLGA, PLGA-PEG, PVA, or combinations thereof.

In one embodiment, the implant includes the biocompatible polymers PLA, PLA-PEG, PVA, or combinations thereof.

In certain embodiments, the implant or the microparticles contain from about 80 weight percent or 89 weight percent to about 99 weight percent PLGA, for example, at least about 80, 85, 90, 95, 96, 97, 98 or 99 weight percent PLGA. In other embodiments, PLA is used in place of PLGA. In yet other embodiments, a combination of PLA, PLGA and/or PCL is used.

In certain examples, the implant or the microparticle includes from about 0.5 weight percent to about 10 weight percent PLGA-PEG, about 0.5 weight percent to about 5 weight percent PLGA-PEG, about 0.5 weight percent to about 4 weight percent PLGA-PEG, about 0.5 weight percent to about 3 weight percent PLGA-PEG, or about 0.1 weight percent to about 1, 2, 5, or 10 weight percent PLGA-PEG. In other embodiments, PLA-PEG or PCL-PEG is used in place of PLGA-PEG. In other embodiments, any combination of PLGA-PEG, PLA-PEG or PCL-PEG is used in the polymeric composition with any combination of PLGA, PLA or PCL. Each combination is considered specifically described as if set out individually herein. In certain embodiments, the polymeric formulation includes up to about 1, 2, 3, 4, 5, 6, 10, or 14% of the selected pegylated polymer.

In certain embodiments, the PLGA polymer has a molecular weight of 30,000 to 60,000 g/mol (also kilodalton, kDa or kD). In certain embodiments, the PLGA polymer has a molecular weight of 40,000 to 50,000 g/mol (for example 40,000; 45,000 or 50,000g/mol). In certain embodiments, the PLA polymer has a molecular weight of 30,000 to 60,000 g/ mol (for example 40,000; 45,000 or 50,000g/mol). In certain embodiments, the PCL polymer is used in the same range of kDa as described for PLGA or PLA.

In certain embodiments the implant or the microparticle includes 5/95, 10/90, 15/85, 20/80, 25/75, 30/70, 35/65, 40/60, 45/55, 50/50, 55/45, 60/40, 65/35, 70/30, 75/25, 80/20, 85/15, 90/10, 95/5 PLGA as a biodegradable polymer. In certain embodiments, the polymeric implant or the microparticles include 50/50 PLGA as a biodegradable polymer.

Poly lactic acid (PLA), polyglycolic acid (PGA), and poly(D,L4actide-co-glycolide) (PLGA) are poly(a-hydroxyacids). Alternative poly(a-hydroxyacids) include, but are not limited to, poly D,L-lactic acid (PDLLA), polyesters, poly (e-caprolactone), poly (3 -hydroxy -butyrate), poly (s-caproic acid), poly (p-dioxanone), poly (propylene fumarate), poly (ortho esters), polyol/diketene acetals, polyanhydrides, poly (sebacic anhydride) (PSA), poly (carboxybis- carboxyphenoxyphosphazene) (PCPP), poly [bis (p-carboxyphenoxy) methane] (PCPM), copolymers of SA, CPP and CPM (as described in Tamat and Langer in Journal of Biomaterials Science Polymer Edition, 3, 315-353, 1992 and by Domb in Chapter 8 of The Handbook of Biodegradable Polymers , Editors Domb A J and Wiseman R M, Harwood Academic Publishers), and poly (amino acids).

In one embodiment, the implant or the microparticle includes about at least 90 percent hydrophobic polymer and about not more than 10 percent hydrophilic polymer. Examples of hydrophobic polymers include polyesters such as poly lactic acid (PLA), polyglycolic acid (PGA), poly(D,L-lactide-co-glycolide)(PLGA), and poly D,L-lactic acid (PDLLA); polycaprolactone; polyanhydrides, such as polysebacic anhydride, poly(maleic anhydride); and copolymers thereof. Examples of hydrophilic polymers include poly(alkylene glycols) such as polyethylene glycol (PEG), polyethylene oxide (PEO), and polyethylene glycol) amine; polysaccharides; poly(vinyl alcohol) (PVA); polypyrrolidone; polyacrylamide (PAM); polyethylenimine (PEI); poly(acrylic acid); poly(vinylpyrolidone) (PVP); or a copolymer thereof.

In one embodiment, the implant or the microparticle includes about at least 85 percent hydrophobic polymer and at most about 15 percent hydrophilic polymer.

In one embodiment, the implant or the microparticle includes about at least about 80 percent hydrophobic polymer and at most about 20 percent hydrophilic polymer.

In one embodiment, the implant or the microparticle includes PLA. In one embodiment, the PLA is acid-capped. In one embodiment, the PLA is ester-capped.

In certain embodiments, the implant or the microparticles of the present invention are a blend of two polymers, for example (i) a PLGA polymer or PLA polymer as described herein and (ii) a PLGA-PEG or PLA-PEG copolymer. In another embodiment, the implant or the microparticles is a blend of three polymers, such as, for example, (i) a PLGA polymer; (ii) a PLA polymer; and (iii) a copolymer of PLGA-PEG or PLA-PEG. In an additional embodiment, the implant or the microparticles is a blend of (i) a PLA polymer; (ii) a PLGA polymer; (iii) a PLGA polymer that has a different ratio of lactide and glycolide monomers than the PLGA in (ii); and (iv) a PLGA-PEG or PLA-PEG copolymer. Any ratio of lactide and glycolide in the PLGA can be used that achieves the desired therapeutic effect. In certain illustrative non-limiting embodiments, the ratio of PLA to PLGA by weight in a polymer blend as described is 77/22, 69/30, 49/50, 54/45, 59/40, 64/35, 69/30, 74/25, 79/20, 84/15, 89/10, 94/5, or 99/1.

In certain embodiments, a blend of three polymers that has (i) PLA (ii) PLGA (iii) PLGA with a different ratio of lactide and glycolide monomers than PLGA in (ii) wherein the ratio by weight is 74/20/5 by weight, 69/20/10 by weight, 69/25/5 by weight, or 64/20/15 by weight. In certain embodiments, the PLGA in (ii) has a ratio of lactide to glycolide of 85/15, 75/25, or 50/50. In certain embodiments the PLGA in (iii) has a ratio of lactide to glycolide of 85/15, 75/25, or 50/50.

In certain aspects, the implant or the microparticles comprises a blend of PLGA or PLA and PEG-PLGA, including but not limited to (i) PLGA + approximately by weight 1% PEG-PLGA or (ii) PLA + approximately by weight 1% PEG-PLGA. In certain aspects, the implant or the microparticles comprises a blend of (iii) PLGA/PLA + approximately by weight 1% PEG-PLGA. In certain embodiments, the blend of PLA, PLGA, or PLA/PGA with PLGA-PEG contains approximately from about 0.5% to about 10% by weight of a PEG-PLGA, from about 0.5% to about 5% by weight of a PEG-PLGA, from about 0.5% to about 4% by weight of a PEG-PLGA, from about 0.5% to about 3% by weight of a PEG-PLGA, from about 1.0% to about 3.0% by weight of a PEG-PLGA, from about 0.1% to about 10% of a PEG-PLGA, from about 0.1% to about 5% of a PEG-PLGA, from about 0.1% to about 1% PEG-PLGA, or from about 0.1% to about 2% PEG-PLGA.

In certain non-limiting embodiments, the ratio by weight percent of PLGAto PEG-PLGA in a two polymer blend as described is in the range of about or between the ranges of 40/1, 45/1, 50/1, 55/1, 60/1, 65/1, 70/1, 75/1, 80/1, 85/1, 90/1, 95/1, 96/1, 97/1, 98/1, 99/1. The PLGA can be acid or ester capped. In non-limiting aspects, the drug can be delivered in a two polymer blend of PLGA75:25 4A + approximately 1% PEG-PLGA50:50; PLGA85:15 5A + approximately 1% PEG-PLGA5050; PLGA75:25 6E + approximately 1% PEG-PLGA50:50; or PLGA50:50 2A + approximately 1% PEG-PLGA50:50.

In certain non -limiting embodiments, the ratio by weight percent of PLA/PLGA-PEG in a polymer blend as described is in the range of about or between the ranges of 40/1, 45/1, 50/1, 55/1, 60/1, 65/1, 70/1, 75/1, 80/1, 85/1, 90/1, 95/1, 96/1, 97/1, 98/1, 99/1. The PLA can be acid capped or ester capped. In cetain aspects, the PLA is PLA 4.5A. In non-limiting aspects, the drug is delivered in a blend of PLA 4.5A + 1% PEG-PLGA.

The PEG segment of the PEG-PLGA may have, for example, in non-limiting embodiments, a molecular weight of at least about or between 1 kDa, 2 kDa, 3 kDa, 4 kDa, 5 kDa, 6 kDa, 7 kDa, 8 kDa, 9 kDa, or 10 kDa, and typically not greater than 10 kDa, 15 kDa, 20 kDa, or 50 kDa, or in some embodiments, 6 kDa, 7 kDa, 8 kDa, or 9kDa. In certain embodiment, the PEG segment of the PEG-PLGA has a molecular weight between about 3 kDa and about 7 kDa or between about 2 kDa and about 7 kDa. Non-limiting examples of the PLGA segment of the PEG-PLGA is PLGA50:50, PLGA75:25, or PLGA85:15. In one embodiment, the PEG-PLGA segment is PEG (5 kDa)-PLGA50:50.

In a blend of PLGA + PEG-PLGA, any ratio of lactide and glycolide in the PLGA or the PLGA-PEG can be used that achieves the desired therapeutic effect. Non-limiting illustrative embodiments of the ratio of lactide/glycolide in the PLGA or PLGA-PEG are in the range of about or between the ranges of 5/95, 10/90, 15/85, 20/80, 25/75, 30/70, 35/65, 40/60, 45/55, 50/50, 55/45, 60/40, 65/35, 70/30, 75/25, 80/20, 85/15, 90/10, or 95/5. In certain embodiments, the PLGA is a block co-polymer, for example, diblock, triblock, multiblock, or star-shaped block. In certain embodiments, the PLGA is a random co-polymer. In certain aspects, the PLGA is PLGA75:254A; PLGA85:15 5A; PLGA75:25 6E; or PLGA50:50 2A.

In one embodiment, the ratio of PLA and/or PLGA to hydrophobic polymer covalently bound to a hydrophilic polymer in the microparticle or implant is between about 40/1 to about 120/1 by weight. In certain embodiments, the ratio by weight of PLA and/or PLGA to hydrophobic polymer covalently bound to hydrophilic polymer in the microparticle is about 45/1, 50/1, 55/1, 60/1, 65/1, 70/1, 75/1, 80/1, 85/1, 90/1, 95/1, 96/1, 97/1, 98/1, 99/1, 99.5/1, 99.9/1, 100/1, 101/1, 102/1, 103/1, 104/1, 105/1, or greater than 105/1. In one embodiment, the hydrophobic polymer covalently bound to a hydrophilic polymer is PLGA-PEG.

In certain embodiments, the microparticle or implant contains PLA, PLGA, and PLGA- PEG. In certain embodiments, the ratio by weight of PLA/PLGA/PLGA-PEG in the microparticle is about 5/95/1, 10/90/1, 15/85/1, 20/80/1, 25/75/1, 30/70/1, 35/65/1, 40/60/1, 45/55/1, 40/60/1, 45/55/1, 50/50/1, 55/45/1, 60/40/1, 65/35/1, 70/30/1, 75/25/1, 80/20/1, 85/15/1, 90/10/1, 95/5/1, or 100/1/1. In one embodiment, PLA-PEG or PLC-PEG is substituted for PLGA-PEG.

In one embodiment, the microparticle or implant comprises PLA/PLGA45k-PEG5k. The PLA can be ester or acid end-capped. In one embodiment, the PLA is acid end-capped. In certain embodiments, the microparticle or implant comprises PLA/PLGA45k-PEG5k in a ratio by weight of between about 100/1 to 80/20, about 100/1, 95/5, 90/10, 85/15, or 80/20. In certain embodiments, the microparticle or implant comprises PLA/PLGA7525/PLGA45k-PEG5k in a ratio of between about 99/1/1 to 1/99/1, about 99/1/1, 95/5/1, 90/10/1, 85/15/1, 80/20/1, 75/25/1, 70/30/1, 65/35/1, 60/40/1, 55/45/1, 50/50/1, 45/55/1, 40/60/1, 35/65/1, 30/70/1, 25/75/1, 20/80/1, 15/85/1, 10/90/1, 5/95/1, or 1/99/1. The PLGA7525 and PLA can be acid or ester end capped. In one embodiment, both the PLGA7525 and PLA are acid end-capped. In one embodiment, the microparticles comprise PLA/PLGA5050/PLGA45k-PEG5k. In certain embodiments, the microparticle or implant comprise PLA/PLGA5050/PLGA45k-PEG5k in a ratio by weight of about 99/1/1, 95/5/1, 90/10/1, 85/15/1, 80/20/1, 75/25/1, 70/30/1, 65/35/1, 60/40/1, 55/45/1, 50/50/1, 45/55/1, 40/60/1, 35/65/1, 30/70/1, 25/75/1, 20/80/1, 15/85/1, 10/90/1, 5/95/1, or 1/99/1. The PLA and PLGA5050 can be acid or ester end-capped. In one embodiment, both the PLA and PLGA are acid end-capped.

In another embodiment, the implant or the microparticles includes a polyethylene oxide (PEO) or polypropylene oxide (PPO). In certain aspects, the polymer can be a random, block, diblock, triblock or multiblock copolymer (for example, a polylactide, a polylactide-co-glycolide, polyglycolide or Pluronic). For injection into the eye, the polymer is pharmaceutically acceptable and typically biodegradable so that it does not have to be removed.

It should be understood by one skilled in the art that by manufacturing a microparticle from multiple polymers with varied ratios of hydrophobic, hydrophilic, and biodegradable characteristics that the properties of the microparticle can be designed for the target use. As an illustration, a microparticle or implant manufactured with 90 weight percent PLGA and 10 weight percent PEG is more hydrophilic than a microparticle or implant manufactured with 95 weight percent PLGA and 5 weight percent PEG. Further, a microparticle or implant manufactured with a higher content of a less biodegradable polymer will in general degrade more slowly. This flexibility allows the polymeric formulations of the present invention to be tailored to the desired level of solubility, rate of release of pharmaceutical agent, and rate of degradation.

VI. Surfactants

In certain embodiments, the manufacture of the microparticle or the implant of the present invention includes a surfactant. Examples of surfactants include, for example, polyoxyethylene glycol, polyoxypropylene glycol, decyl glucoside, lauryl glucoside, octyl glucoside, polyoxyethylene glycol octylphenol, Triton X-100, glycerol alkyl ester, glyceryl laurate, cocamide MEA, cocamide DEA, dodecyldimethylamine oxide, and poloxamers. Examples of poloxamers include, poloxamers 188, 237, 338 and 407. These poloxamers are available under the trade name Pluronic® (available from BASF, Mount Olive, N.J.) and correspond to Pluronic® F-68, F-87, F- 108 and F-127, respectively. Poloxamer 188 (corresponding to Pluronic® F-68) is a block copolymer with an average molecular mass of about 7,000 to about 10,000 Da, or about 8,000 to about 9,000 Da, or about 8,400 Da. Poloxamer 237 (corresponding to Pluronic® F-87) is a block copolymer with an average molecular mass of about 6,000 to about 9,000 Da, or about 6,500 to about 8,000 Da, or about 7,700 Da. Poloxamer 338 (corresponding to Pluronic® F- 108) is a block copolymer with an average molecular mass of about 12,000 to about 18,000 Da, or about 13,000 to about 15,000 Da, or about 14,600 Da. Poloxamer 407 (corresponding to Pluronic® F-127) is a polyoxyethylene-polyoxypropylene triblock copolymer in a ratio of between about E101 P56 E101 to about E106 P70 E106, or about E101 P56E101, or about E106 P70 E106, with an average molecular mass of about 10,000 to about 15,000 Da, or about 12,000 to about 14,000 Da, or about 12,000 to about 13,000 Da, or about 12,600 Da.

Additional examples of surfactants that can be used in the invention include, but are not limited to, polyvinyl alcohol (which can be hydrolyzed polyvinyl acetate), polyvinyl acetate, Vitamin E-TPGS, poloxamers, cholic acid sodium salt, dioctyl sulfosuccinate sodium, hexadecyltrimethyl ammonium bromide, saponin, TWEEN® 20, TWEEN® 80, sugar esters, Triton X series, L-a-phosphatidylcholine (PC), 1 ,2-dipalmitoylphosphatidycholine (DPPC), oleic acid, sorbitan trioleate, sorbitan mono-oleate, sorbitan monolaurate, polyoxyethylene (20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monooleate, natural lecithin, oleyl polyoxyethylene (2) ether, stearyl polyoxyethylene (2) ether, lauryl polyoxyethylene (4) ether, block copolymers of oxyethylene and oxypropylene, synthetic lecithin, diethylene glycol dioleate, tetrahydrofurfuryl oleate, ethyl oleate, isopropyl myristate, glyceryl monooleate, glyceryl monostearate, glyceryl monoricinoleate, cetyl alcohol, stearyl alcohol, cetylpyridinium chloride, benzalkonium chloride, olive oil, glyceryl monolaurate, com oil, cotton seed oil, sunflower seed oil, lecithin, oleic acid, and sorbitan trioleate.

In certain embodiments, the surfactant is polyvinyl alcohol (PVA). Any molecular weight PVA can be used that achieves the desired results. In certain embodiments, the PVA has a molecular weight of up to about 10, 15, 20, 25, 30, 35 or 40 kd. In some embodiments, the PVA is partially hydrolyzed polyvinyl acetate, including but not limited to, up to about 70, 75, 80, 85, 88, 90 or even 95% hydrolyzed polyvinyl acetate. In certain embodiments, the PVA is about 88% hydrolyzed polyvinyl acetate. In certain embodiments, the PVA polymer has a molecule weight of 20,000 to 40,000 g/mol. In certain embodiments, the PVA polymer has a molecular weight of 24,000 to 35,000 g/mol.

In certain embodiments, the polyvinyl alcohol is a partially hydrolyzed polyvinyl acetate. For example, the polyvinyl acetate is at least about 78% hydrolyzed so that the polyvinyl acetate is substantially hydrolyzed. In one example, the polyvinyl acetate is at least about 88% to 98% hydrolyzed so that the polyvinyl acetate is substantially hydrolyzed.

In some examples, the microparticle or implant contains from about 0.01 percent to about 0.5 percent surfactant, about 0.05 percent to about 0.5 percent surfactant, about 0.1 percent to about 0.5 percent surfactant, or about 0.25 percent to about 0.5 percent surfactant. In some examples, the microparticle or implant contains from about 0.001 percent to about 1 percent surfactant, about 0.005 percent to about 1 percent surfactant, about 0.075 percent to about 1 percent surfactant, or about 0.085 percent to about 1 percent surfactant. In some examples, the microparticle or implant contains from about 0.01 percent to about 5.0 percent surfactant, about 0.05 percent to about 5.0 percent surfactant, about 0.1 percent to about 5.0 percent surfactant, about 0.50 percent to about 5.0 percent surfactant. In some examples, the microparticle or implant contains from about 0.10 percent to about 1.0 percent surfactant or about 0.50 percent to about 1.0 percent. In some embodiments, the microparticle or implant contains up to about 0.10, 0.15, 0.20, 0.25, 0.30, 0.40 or 0.5% surfactant. Any molecular weight surfactant can be used that achieves the desired results. In certain embodiments, the surfactant has a molecular weight of up to about 10, 15, 20, 25, 30, 35 or 40 kd.

In certain embodiments, the surfactant is PVA. In some embodiments, the PVA is partially hydrolyzed polyvinyl acetate, including but not limited to, up to about 70, 75, 80, 85, 88, 90 or even 95% hydrolyzed polyvinyl acetate. In certain embodiments, the PVA is about 88% hydrolyzed polyvinyl acetate. In certain embodiments, the PVA polymer has a molecule weight of 20,000 to 40,000 g/mol. In certain embodiments, the PVA polymer has a molecular weight of 24,000 to 35,000 g/mol.

It should be recognized by one skilled in the art that some surfactants can be used as polymers in the manufacture of the microparticle. It should also be recognized by one skilled in the art that in some manufacture the microparticle or implant may retain a small amount of surfactant which allows further modification of properties as desired.

VII. Excipients

Non-limiting examples of excipients that may be included in the implant or microparticle formulations of the present invention include a sugar, plasticizer, buffering agent, preservative, thermal binder, drug stabilizer, drug solubilizer or drug-release controlling excipient. Other excipients may be added to improve the processability, increase the dissolution rate and bioavailability of timolol and/or the compound of Formula I, control or modulate release of timolol and/or the compound of Formula I, and/or stabilize timolol and/or the compound of Formula I.

Preservatives which may be used include, but are not limited to, sodium bisulfite, sodium bisulfate, sodium thiosulfate, benzalkonium chloride, chlorobutanol, thimerosal, phenylmercuric acetate, phenylmercuric nitrate, methylparaben, polyvinyl alcohol and phenylethyl alcohol. Examples of buffering agents that may be employed include, but are not limited to, sodium carbonate, sodium borate, sodium phosphate, sodium acetate, croscarmellose sodium, sodium bicarbonate, and the like, as approved by the FDA for the desired route of administration. Electrolytes such as sodium chloride and potassium chloride may also be included in the formulation.

Non-limiting examples of sugars include sucrose, mannitol, trehalose, glucose, arabinose, fucose, mannose, rhamnose, xylose, D-xylose, glucose, fructose, ribose, D-ribose, galactose, dextrose, dextran, lactose, maltodextrin, maltose, glycerol, erythritol, threitol, arabitol, xylitol, ribitol, sorbitol, galactitol, fucitol, iditol, inositol, volemitol, isomalt, maltitol, lactitol, maltotriitol, maltotetraitol, and polyglycitol. In an alternative embodiment, the sugar is selected from aspartame, saccharin, stevia, sucralose, acesulfame potassium, advantame, alitame, neotame, and sucralose.

Non-limiting examples of plasticizers include polyethylene glycol, glycerin, poloxamer 188, MGHS 40, tri ethyl citrate, benzyl alcohol, polyethylene glycol, N-methyl-2-pyrrolidone (NMP), 2-pyrrolidone, DMSO, triacetin, benzyl acetate, benzyl benzoate, acetyltributyl citrate, dibutyl sebacate, dimethylphthalate, tributyl O-acetylcitrate, ethanol, methanol, polysorbate 80, ethyl acetate, propylene carbonate, isopropyl acetate, methyl acetate, methyl ethyl ketone, butyl lactate, and isovaleric acid.

Non-limiting examples of stabilizing and solubilizing agents include acacia, alginic acid, colloidal silicone dioxide, cellulose, carboxymethylcellulose calcium, gelatin, glyceryl monostearate, hydroxy propyl cellulose, hydroxyl propyl methyl cellulose, hypromellose, methyl cellulose, Polysorbate 80, propylene glycol, Polaxamer 407 or 188, polyoxyl40 stearate, sucrose, sodium alginate, and sorbiton monooleate.

In certain embodiments, a formulation of the present invention, for example, an implant comprises a thermal binder. Non-limiting examples of thermal binders include cross-linked polyvinylpyrrolidone or microcrystalline cellulose, alginate, candelilla wax, carnuba wax, corn starch, copolyvidone, starch pregelatinized, acacia gum, gum tragacanth, gelatin, sucrose, starch paste, sodium alginate, methyl cellulose, ethyl cellulose, hydroxy propyl methyl cellulose, and magnesium aluminum silicate.

In certain embodiments a formulation of the present invention, for example, an implant contains an excipient for hot-melt extrusion. Non-limiting examples of an excipient for hot melt extrusion include a polymer. Non-limiting examples of polyvinyl-based homopolymers include poly(vinyl pyrrolidone) (Kollidon®), poly(vinyl acetate) (Sentry® plus), and polyvinyl alcohol (Elvanol®). Non-limiting examples of polyvinyl-based copolymers include polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®), polyvinyl alcohol-polyethylene glycol Copolymer (Kollicoat IR®), polyvinylpyrrolidone- co-vinyl acetate (Kollidon® VA64), poly(ethylene-co-vinyl acetate) (Elvax® 40W), ethylene-vinyl acetate copolymer (Evatane®), poly(vinyl acetate-co-methacrylic acid) (CIBA-I). Non-limiting examples of macrogols (PEG) or polyethylenoxides (PEO) homopolymers include polyehtyleneglycol (Carbowax®) and polyethyleneoxide (Poly ox® WSR). Non-limiting examples of poly-acrylate homopolymers include carbomer (Carbopol® 974P) and polycarbophil (Noveon® AA-1). Non limiting examples of polymethacrylate copolymers include poly(dimethylaminoethylmethacrylate-comethacrylic esters) (Eudragit® E), ammonio methacrylate copolymer (Eudragit® RS/RL), poly(methyl acrylate-co-methyl methacrylateco-methacrylic acid) 7:3:1 (Eudragit® 4135F), poly(methacrylic acid-co-methyl methacrylate) 1:2 (Eudragit® S), and poly(methacylic acid-co-ethyl acrylate) 1:1 (Eudragit® L100-55). Non-limiting examples of polysaccharides, such as cellulose derivatives or chitosans, include hydroxypropyl methylcellulose acetate succinate (Aqoat-AS®), hydroxypropyl cellulose (Klucel®), hydroxypropyl methylcellulose (Methocel®), ethyl cellulose (Ethocel®), cellulose acetate butyrate (CAB 381-0.5), cellulose acetate phthalate, hydroxypropyl methylcellulose acetate succinate (Aqoat-AS®), hydroxypropyl methylcellulose phthalate, and chitosan. A non-limiting example of a polypropylene oxide copolymer is a poloxamer (Lutrol® F127).

VIII. Sustained release of pharmaceutically active compound

The rate of release of timolol and/or the compound of Formula I can be related to the concentration of the compound dissolved in the microparticles or the implants of the present invention. In some embodiments, the polymeric composition of the microparticle or implant includes non-therapeutic agents that are selected to provide a desired solubility of timolol and/or the compound of Formula I in the microparticle or implant. The selection of the polymeric composition can be made to provide the desired solubility of timolol and/or the compound of Formula I in the microparticle or the implant, for example, a hydrogel may promote solubility of a hydrophilic material. In some embodiments, functional groups can be added to the polymer to increase the desired solubility of timolol and/or the compound of Formula I in the microparticle or the implant. In some embodiments, additives may be used to control the release kinetics of timolol and/or the compound of Formula I, for example, the additives may be used to control the concentration of timolol and/or the compound of Formula I by increasing or decreasing the solubility of timolol and/or the compound of Formula I in the polymer so as to control the release kinetics of timolol and/or the compound of Formula I. The solubility may be controlled by including appropriate molecules and/or substances that increase and/or decrease the solubility of the dissolved form of timolol and/or the compound of Formula I in the microparticle or implant. The solubility of timolol and/or the compound of Formula I may be related to the hydrophobic and/or hydrophilic properties of the microparticle or the implant and timolol and/or the compound of Formula I. Oils and hydrophobic molecules can be added to the polymer(s) to increase the solubility of timolol and/or the compound of Formula I in the microparticle or the implant.

Instead of, or in addition to, controlling the rate of migration based on the concentration of timolol and/or the compound of Formula I dissolved in the microparticle or implant, the surface area of the polymeric composition can be controlled to attain the desired rate of drug migration out of the microparticle or implant comprising timolol and/or the compound of Formula I. For example, a larger exposed surface area will increase the rate of migration of timolol and/or the compound of Formula I to the surface, and a smaller exposed surface area will decrease the rate of migration of timolol and/or the compound of Formula I to the surface. The exposed surface area can be increased in any number of ways, for example, by castellation of the exposed surface, a porous surface having exposed channels connected with the tear or tear film, indentation of the exposed surface, or protrusion of the exposed surface. The exposed surface can be made porous by the addition of salts that dissolve and leave a porous cavity once the salt dissolves. In the present invention, these trends can be used to decrease the release rate of the active material from the polymeric composition by avoiding these paths to quicker release. For example, the surface area can be minimized, or channels can be avoided.

The system of the invention can allow for the pharmaceutically active compound release to be sustained for some time, for example, release can be sustained for at least about 2 hours, at least about 4 hours, at least about 6 hours, at least about 10 hours, at least about 12 hours, at least about 24 hours, at least 48 hours, at least a week, more than one week, at least a month, at least two months, at least three months, at least four months, at least five months, at least six months, at least seven months, at least eight months, at least nine months, at least ten months, at least eleven months, at least twelve months, or more.

In certain embodiments, the microparticles that produce a microparticle depot in vivo release timolol and/or the compound of Formula I without a burst of more than about 1 percent to about 5 percent of total payload over a 24 hour period or a 12 hour period. In certain embodiments, the microparticles or the implant releases timolol and/or the compound of Formula I without a burst of more than about 1 percent to about 5 percent of total payload over a 24 hour period or a 12 hour period.

In certain embodiments, the microparticles that produce a microparticle depot in vivo release timolol and/or the compound of Formula I without a burst of more than about 10 percent of total payload over a 24 hour period or a 12 hour period. In certain embodiments, the microparticles or the implant releases timolol and/or the compound of Formula I without a burst of more than about 10 percent of total payload over a 24 hour period or a 12 hour period.

In certain embodiments, the solid aggregating microparticles that produce a microparticle depot in vivo release timolol and/or the compound of Formula I without a burst of more than about 15 percent of total payload over a 24 hour period or a 12 hour period. In certain embodiments, the microparticles or the implant releases timolol and/or the compound of Formula I without a burst of more than about 15 percent of total payload over a 24 hour period or a 12 hour period.

In certain embodiments, the solid aggregating microparticles that produce a microparticle depot in vivo release timolol and/or the compound of Formula I without a burst of more than about 20 percent of total payload over a 24 hour period or a 12 hour period. In certain embodiments, the microparticles or the implant releases timolol and/or the compound of Formula I without a burst of more than about 20 percent of total payload over a 24 hour period or a 12 hour period.

In certain embodiments, timolol and/or the compound of Formula I is released in an amount effective to have a desired local or systemic physiological or pharmacologically effect.

In certain embodiments, delivery of timolol and/or the compound of Formula I means that the compound of Formula I is released from the composition into the environment around the composition, for example, the vitreal fluid. IX. Pharmaceutically Acceptable Carriers

The compositions of the present invention can be administered in any suitable pharmaceutically acceptable carrier. The carrier can be present in an amount effective in providing the desired viscosity to the drug delivery system. Advantageously, the viscous carrier is present in an amount ranging from about 0.5 weight percent to about 95 weight percent of the drug delivery composition. The specific amount of the viscous carrier used depends upon a number of factors including, for example and without limitation, the specific viscous carrier used, the molecular weight of the viscous carrier used, the viscosity desired for the present drug delivery system being produced and/or used and like factors. Examples of useful viscous carriers include, but are not limited to, hyaluronic acid, sodium hyaluronate, carbomers, polyacrylic acid, cellulosic derivatives, polycarbophil, polyvinylpyrrolidone, gelatin, dextrin, polysaccharides, polyacrylamide, polyvinyl alcohol (which can be partially hydrolyzed polyvinyl acetate), polyvinyl acetate, derivatives thereof and mixtures thereof.

Typically, the composition comprises from about 20 percent to about 80 percent of the injectable formulations described herein and from about 20 percent to about 80 percent carrier; from about 30 percent to about 70 percent of the injectable formulations described herein and from about 30 percent to about 70 percent carrier; e.g., the composition may comprise from about 40 percent to about 60 percent of the injectable formulations described herein and from about 40 percent to about 60 percent carrier; the composition may comprise about 50 percent of the formulations described herein and about 50 percent carrier. The aforementioned percentages all refer to percentage by weight.

In certain embodiments, the composition contains the microparticles of the present invention and has a range of concentration of the microparticles of about 50-700 mg/ml, 500 or less mg/ml, 400 or less mg/ml, 300 or less mg/ml, 200 or less mg/ml, or 150 or less mg/ml.

The carrier can also be an aqueous carrier. Example of aqueous carriers include, but are not limited to, an aqueous solution or suspension, such as saline, plasma, bone marrow aspirate, buffers, such as Hank's Buffered Salt Solution (HBSS), HEPES (4-(2 -hydroxy ethyl)- 1- piperazineethanesulfonic acid), Ringers buffer, Pro Vise®, diluted Pro Vise®, Pro Vise® diluted with PBS, Krebs buffer, Dulbecco's PBS, normal PBS; sodium hyaluronate solution (HA, 5 mg/mL in PBS), simulated body fluids, plasma platelet concentrate and tissue culture medium or an aqueous solution or suspension comprising an organic solvent. In one embodiment, the carrier is PBS.

In one embodiment, the carrier is HA, 5 mg/mL in PBS.

In one embodiment, the carrier is Pro Vise® diluted with water.

In one embodiment, the carrier is Pro Vise® dilution in PBS.

In one embodiment, the carrier is Pro Vise® 5-fold diluted with water.

In one embodiment, the carrier is Pro Vise® 5-fold dilution in PBS.

In one embodiment, the carrier is Pro Vise® 10-fold diluted with water.

In one embodiment, the carrier is Pro Vise® 10-fold dilution in PBS.

In one embodiment, the carrier is Pro Vise® 20-fold dilution with water.

In one embodiment, the carrier is Pro Vise® 20-fold dilution in PBS.

In one embodiment, the carrier is HA, 1.25 mg/mL in an isotonic buffer solution with neutral pH.

In one embodiment, the carrier is HA, 0.625 mg/mL in an isotonic buffer solution with neutral pH.

In one embodiment, the carrier is HA, 0.1-5.0 mg/mL in PBS.

In one embodiment, the carrier is HA, 0.5-4.5 mg/mL in PBS.

In one embodiment, the carrier is HA, 1.0-4.0 mg/mL in PBS.

In one embodiment, the carrier is HA, 1.5-3.5 mg/mL in PBS.

In one embodiment, the carrier is HA, 2.0-3.0 mg/mL in PBS.

In one embodiment, the carrier is HA, 2.5-3.0 mg/mL in PBS.

The carrier may, optionally, contain one or more suspending agent. The suspending agent may be selected from carboxy methylcellulose (CMC), mannitol, polysorbate, poly propylene glycol, poly ethylene glycol, gelatin, albumin, alginate, hydroxyl propyl methyl cellulose (HPMC), hydroxyl ethyl methyl cellulose (HEMC), bentonite, tragacanth, dextrin, sesame oil, almond oil, sucrose, acacia gum and xanthan gum and combinations thereof.

In one embodiment, one or more additional additives or excipients or delivery enhancing agents may also be included e.g., surfactants and/or hydrogels, in order to further influence release rate and/or improve in vivo aggregation of microparticles.

In certain embodiments, the diluent contains approximately from about 0.01% to about 10% by weight of additive or excipient, from about 0.01% to about 0.1% by weight of additive or excipient, from about 0.05% to about 0.5% by weight of additive or excipient, from about 0.1% to about 1.0% by weight of additive or excipient, from about 0.1% to about 10% by weight of additive or excipient, from about 0.5% to about 5% by weight of additive or excipient, from about 0.5% to about 4% by weight of additive or excipient, from about 0.5% to about 3% by weight of additive or excipient, from about 0.5% to about 2.0% by weight of additive or excipient, from about 0.1% to about 0.5% by weight of additive or excipient, from about 0.1% to about 0.25% by weight of additive or excipient, from about 0.2% to about 2% by weight of additive or excipient, or from about 0.01% to about 0.05% by weight of additive or excipient.

X. Methods of Administration

In one embodiment, the compositions described herein that comprise timolol and/or a compound of Formula I or a pharmaceutically acceptable salt thereof, optionally in combination with a pharmaceutically acceptable carrier, excipient, or diluent are used for the treatment of a disorder, including a human disorder. In one embodiment, the composition is a pharmaceutical composition for treating an eye disorder or eye disease. In certain embodiments, the microparticles or the implants of the present invention, as described herein, are used to treat a medical disorder which is glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves. In another embodiment more generally, the disorder treated is allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy. In certain embodiments, the surface-modified microparticles or the implants are used to reduce intraocular pressure in a host in need thereof with glaucoma.

In certain embodiments, the glaucoma is primary open angle glaucoma (POAG), primary angle closure glaucoma, pediatric glaucoma, pseudo-exfoliative glaucoma, pigmentary glaucoma, traumatic glaucoma, neovascular glaucoma, or irido corneal endothelial glaucoma (primary open angle glaucoma is also known as chronic open angle glaucoma, chronic simple glaucoma and glaucoma simplex). In certain embodiments, the glaucoma is primary open angle glaucoma (POAG).

Another embodiment is provided that includes the administration of the microparticles or the implants of the present invention comprising an effective amount of a compound of Formula I or a pharmaceutically acceptable salt thereof to a host to treat an ocular or other disorder that can benefit from local delivery. The therapy can be delivered to the anterior or posterior chamber of the eye. In specific aspects, a microparticle or implant comprising an effective amount of a compound of Formula I or a pharmaceutically acceptable salt thereof is administered to treat a disorder of the cornea, conjunctiva, aqueous humor, iris, ciliary body, lens sclera, choroid, retinal pigment epithelium, neural retina, optic nerve, or vitreous humor.

Any of the compositions described can be administered to the eye as described further herein in any desired form of administration, including via intravitreal, intrastromal, intracameral, subtenon, sub-retinal, retrobulbar, peribulbar, suprachoroidal, subchoroidal, conjunctival, subconjunctival, episcleral, posterior juxtascleral, circumcorneal, tear duct injections, or through a mucus, mucin, or a mucosal barrier, in an immediate or controlled release fashion. In certain embodiments, the surface-modified aggregating microparticles or the implants of the present invention are administered via intravitreal administration. In certain embodiments, the surface- modified aggregating microparticles or the implants of the present invention are administered via suprachoroidal administration. Methods of treating or preventing ocular disorders, including glaucoma, myopia, presbyopia, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), a disorder requiring neuroprotection such as to regenerate/repair optic nerves, allergic conjunctivitis, anterior uveitis, cataracts, dry or wet age- related macular degeneration (AMD) or diabetic retinopathy are disclosed comprising administering a therapeutically effective amount of a surface treated microparticle or an implant of the present invention comprising a compound of Formula I or a pharmaceutically acceptable salt thereof to a host, including a human, in need of such treatment. In certain embodiments, the host is a human.

In another embodiment, an effective amount of a microparticle or an implant comprising a pharmaceutically active compound is provided to decrease intraocular pressure (IOP) caused by glaucoma. In an alternative embodiment, an effective amount of a surface treated microparticle or an implant comprising a pharmaceutically active compound is provided to decrease intraocular pressure (IOP), regardless of whether it is associated with glaucoma.

In certain embodiments, the disorder is associated with an increase in intraocular pressure (IOP) caused by potential or previously poor patient compliance to glaucoma treatment. In yet another embodiment, the disorder is associated with potential or poor neuroprotection through neuronal nitric oxide synthase (NOS). The surface treated microparticle or implant comprising a compound of Formula I or a pharmaceutically acceptable salt thereof provided herein may thus dampen or inhibit glaucoma in a host, by administration of an effective amount in a suitable manner to a host, typically a human, in need thereof.

Methods for the treatment of a disorder associated with glaucoma, increased intraocular pressure (IOP), optic nerve damage caused by either high intraocular pressure (IOP) or neuronal nitric oxide synthase (NOS) are provided that includes the administration of an effective amount of a surface treated microparticle or an implant comprising a compound of Formula I or a pharmaceutically acceptable salt thereof are also disclosed.

Additional non-limiting exemplary eye disorders or diseases treatable with the composition include age related macular degeneration, alkaline erosive keratoconjunctivitis, allergic conjunctivitis, allergic keratitis, anterior uveitis, Behcet's disease, blepharitis, blood-aqueous barrier disruption, chorioiditis, chronic uveitis, conjunctivitis, contact lens-induced keratoconjunctivitis, corneal abrasion, corneal trauma, corneal ulcer, crystalline retinopathy, cystoid macular edema, dacryocystitis, diabetic keratopathy, diabetic macular edema, diabetic retinopathy, dry eye disease, dry age-related macular degeneration, eosinophilic granuloma, episcleritis, exudative macular edema, Fuchs' Dystrophy, giant cell arteritis, giant papillary conjunctivitis, glaucoma, glaucoma surgery failure, graft rejection, herpes zoster, inflammation after cataract surgery, iridocorneal endothelial syndrome, iritis, keratoconjunctivitis sicca, keratoconjunctivitis inflammatory disease, keratoconus, lattice dystrophy, map-dot-fmgerprint dystrophy, necrotic keratitis, neovascular diseases involving the retina, uveal tract or cornea, for example, neovascular glaucoma, corneal neovascularization, neovascularization resulting following a combined vitrectomy and lensectomy, neovascularization of the optic nerve, and neovascularization due to penetration of the eye or contusive ocular injury, neuroparalytic keratitis, non-infectious uveitis ocular herpes, ocular lymphoma, ocular rosacea, ophthalmic infections, ophthalmic pemphigoid, optic neuritis, panuveitis, papillitis, pars planitis, persistent macular edema, phacoanaphylaxis, posterior uveitis, post-operative inflammation, proliferative diabetic retinopathy, proliferative sickle cell retinopathy, proliferative vitreoretinopathy, retinal artery occlusion, retinal detachment, retinal vein occlusion, retinitis pigmentosa, retinopathy of prematurity, rubeosis iritis, scleritis, Stevens- Johnson syndrome, sympathetic ophthalmia, temporal arteritis, thyroid associated ophthalmopathy, uveitis, vernal conjunctivitis, vitamin A insufficiency-induced keratomalacia, vitritis, wet age-related macular degeneration, neovascular age-related macular degeneration, dry age-related macular degeneration, myopia, and presbyonia.

In one aspect of the present invention, an effective amount of a compound of Formula I or a pharmaceutically acceptable salt thereof as described herein is incorporated into a microparticle or implant, e.g., for convenience of delivery and/or sustained release delivery. The use of materials in micrometer scale provides one the ability to modify fundamental physical properties such as solubility, diffusivity, and drug release characteristics. These micrometer scale agents may provide more effective and/or more convenient routes of administration, lower therapeutic toxicity, extend the product life cycle, and ultimately reduce healthcare costs. As therapeutic delivery systems, surface treated microparticles and implants can allow targeted delivery and sustained release.

In another aspect of the present invention, the surface treated microparticle or implant is coated with a surface agent.

The implants of the present invention may be inserted into the eye, for example the vitreous chamber of the eye, by a variety of methods, including placement by forceps or by trocar following making a 2-3 mm incision in the sclera. The method of placement may influence the therapeutic component or drug release kinetics. For example, delivering the implant with a trocar may result in placement of the implant deeper within the vitreous than placement by forceps, which may result in the implant being closer to the edge of the vitreous. The location of the implant may influence the concentration gradients of therapeutic component or drug surrounding the element, and thus influence the release rates (e.g., an element placed closer to the edge of the vitreous may result in a slower release rate).

The implants of the present invention may also, or alternatively, be inserted into the subconjunctival space such as by injection or surgical insertion. Applicants are aware that effective retinal delivery is effectively provided by such subconjunctival administration.

XI. Manufacture of microparticles Microparticle Formation

Microparticles can be formed using any suitable method for the formation of polymer microparticles known in the art. The method employed for particle formation will depend on a variety of factors, including the characteristics of the polymers present in the drug or polymer matrix, as well as the desired particle size and size distribution. The type of drug(s) being incorporated in the microparticles may also be a factor as some drugs are unstable in the presence of certain solvents, in certain temperature ranges, and/or in certain pH ranges.

Particles having an average particle size of between 1 micron and 100 microns are useful in the compositions described herein. In typical embodiments, the particles have an average particle size of between 1 micron and 40 microns, more typically between about 10 micron and about 40 microns, more typically between about 20 micron and about 40 microns. The particles can have any shape but are generally spherical in shape.

In circumstances where a monodisperse population of particles is desired, the particles may be formed using a method which produces a monodisperse population of microparticles. Alternatively, methods producing polydispersed microparticle distributions can be used, and the particles can be separated using methods known in the art, such as sieving, following particle formation to provide a population of particles having the desired average particle size and particle size distribution. Common techniques for preparing microparticles include, but are not limited to, solvent evaporation, hot melt particle formation, solvent removal, spray drying, phase inversion, coacervation, and low temperature casting. Suitable methods of particle formulation are briefly described below. Pharmaceutically acceptable excipients, including pH modifying agents, disintegrants, preservatives, and antioxidants, can optionally be incorporated into the particles during particle formation.

In certain embodiments, surface treated microparticles including a compound of Formula I or a pharmaceutically acceptable salt thereof are obtained by forming an emulsion and using a bead column as described in, for example, US 8,916,196.

In certain embodiments, surface treated microparticles including a compound of Formula I or a pharmaceutically acceptable salt thereof are obtained by using a vibrating mesh or microsieve.

In certain embodiments, surface treated microparticles including a compound of Formula I or a pharmaceutically acceptable salt thereof are obtained by using slurry sieving.

The processes of producing microspheres described herein are amenable to methods of manufacture that narrow the size distribution of the resultant particles. In certain embodiments, the particles are manufactured by a method of spraying the material through a nozzle with acoustic excitation (vibrations) to produce uniform droplets. A carrier stream can also be utilized through the nozzle to allow further control of droplet size. Such methods are described in detail in: Berkland, C., K. Kim, et al. (2001). "Fabrication of PLG microspheres with precisely controlled and monodisperse size distributions." J Control Release 73(1): 59-74; Berkland, C., M. King, et al. (2002). "Precise control of PLG microsphere size provides enhanced control of drug release rate." J Control Release 82(1): 137-147; Berkland, C., E. Pollauf, et al. (2004). "Uniform double- walled polymer microspheres of controllable shell thickness." J Control Release 96(1): 101-111.

In another embodiment, microparticles of uniform size can be manufactured by methods that utilize microsieves of the desired size. The microsieves can either be used directly during production to influence the size of microparticles formed, or alternatively post production to purify the microparticles to a uniform size. The microsieves can either be mechanical (inorganic material) or biological in nature (organic material such as a membrane). One such method is described in detail in US patent 8,100,348. In certain embodiments, the surface treated microparticles have a particle size of 25 < Dv50 < 40 pm, Dv90 <45 pm.

In certain embodiments, the surface treated microparticles have a particle size of DvlO >

10 pm.

In certain embodiments, the process of for preparing a microparticle or lyophilized or otherwise solidified material thereof or a suspension thereof, leading to an aggregated microparticle depot in vivo , can be used in combination with a selected method for forming aggregating microparticles described in U.S.S.N. 15/349,985 and PCT/US16/61706 (and the resulting materials thereof). For example, methods include providing solid aggregating microparticles that include at least one biodegradable polymer, wherein the solid aggregating microparticles have a solid core, include a therapeutic agent, have a modified surface which has been treated under mild conditions at a temperature, that may optionally be at or less than about 18 °C, to remove surface surfactant, are sufficiently small to be injected in vivo , and are capable of aggregating in vivo to form at least one aggregated microparticle depot of at least 500 pm in vivo to provide sustained drug delivery in vivo for at least three months, four months, five months, six months seven months, eight months, nine months or more. In certain embodiments, sustained drug deliver in vivo is provided for up to one year. The solid aggregating microparticles are suitable, for example, for an intravitreal injection.

As an illustration, the surface-modified solid aggregating microparticles can be prepared by the following process:

A. a first step of preparing microparticles comprising one or more biodegradable polymers by dissolving or dispersing the polymer(s) and a therapeutic agent in one or more solvents to form a polymer and therapeutic agent solution or dispersion, mixing the polymer and the therapeutic agent solution or dispersion with an aqueous phase containing a surfactant to produce solvent-laden microparticles and then removing the solvent(s) to produce polymer microparticles that contain the therapeutic agent, polymer and surfactant; and

B. a second step of mildly treating the surface of microparticles of step (i) at a temperature at or below about 18, 15, 10, 8 or 5 °C optionally up to about 1, 2, 3, 4, 5, 10, 30, 40, 50, 60, 70, 80, 90 100, 11, 120 or 140 minutes with an agent that removes surface surfactant, surface polymer, or surface oligomer in a manner that does not significantly produce internal pores; and C. isolating the surface treated microparticles.

In certain embodiments, the microparticles can be further subjected to one or more processes selected from 1) vacuum treatment prior to lyophilization or other form of reconstitutable solidification, or after the step of reconstitution wherein the microparticles are suspended in a diluent and the suspension is placed under vacuum prior to use; 2) excipient addition, wherein an excipient is added prior to lyophilization; and 3) sonication, prior to lyophilization or other form of reconstitutable solidification, or after the step of reconstitution; 4) sealing the vial containing the dry powder of particles under vacuum, including but not limited to high vacuum; or 5) pre-wetting (i.e., resuspending) the microparticles in a diluent for 2-24 hours before injecting into the eye, for example in a hyaluronic acid solution or other sterile solution suitable for ocular injection.

The process of these steps can be achieved in a continuous manufacturing line or via one step or in step-wise fashion as appropriate. The optional process above can be carried out following isolation of the microparticles and/or upon reconstitution prior to injection. In certain embodiments, the surface treated solid biodegradable microparticles do not significantly aggregate during the manufacturing process. In another embodiment, the surface treated solid biodegradable microparticles do not significantly aggregate when resuspended and loaded into a syringe. In some embodiments, the syringe is approximately 30, 29, 28, 27, 26 or 25 gauge, with either normal or thin wall.

In certain embodiments, the microparticles are prepared without one or more biodegradable polymers.

In one nonlimiting embodiment, a process for preparing a suspension comprising a microparticle and a compound of Formula I or a pharmaceutically acceptable salt thereof encapsulated in the microparticle and the resulting materials thereof; comprises:

(a) preparing a solution or suspension (organic phase) comprising: (i) PLGA or PLA or PLA and PLGA, (ii) PLGA-PEG or PLA-PEG (iii) a compound of Formula I or a pharmaceutically acceptable salt thereof, for example, as described herein and (iv) one or more organic solvents; (b) preparing an emulsion in an aqueous polyvinyl alcohol (PVA) solution (aqueous phase) by adding the organic phase into the aqueous phase and mixing them until particle formation (for example at about 3,000 to about 10,000 rpm for about 1 to about 30 minutes);

(c) removing additional solvent as necessary using known techniques;

(d) centrifuging or causing the sedimentation of the microparticle that is loaded with a pharmaceutically active compound or prodrug thereof;

(e) optionally removing additional solvent and/or washing the microparticle loaded with the pharmaceutically active compound or prodrug thereof with water;

(f) filtering the microparticle loaded with pharmaceutically active compound or prodrug thereof to remove aggregates or particles larger than the desired size;

(g) optionally lyophilizing the microparticle comprising the pharmaceutically active compound and storing the microparticle as a dry powder in a manner that maintains stability for up to about 6, 8, 10, 12, 20, 22, or 24 months or more; and

(h) optionally improving the aggregation potential of the particles by subjecting the particles to at least one process selected from 1) vacuum treatment prior to step (g), or after reconstitution wherein the microparticles are suspended in a diluent and the suspension is placed under vacuum; 2) excipient addition, wherein an excipient is added prior to lyophilization; and 3) sonication prior to step (g), or during reconstitution wherein the microparticles are suspended in a diluent and sonicated; 4) sealing the vial containing the dry powder of particles under vacuum, including but not limited to high vacuum; or 5) pre wetting (i.e., resuspending) the microparticles in a diluent for 2-24 hours before injecting into the eye, for example in a hyaluronic acid solution or other sterile solution suitable for ocular injection.

Vacuum Treatment

In certain embodiments, the process for providing the microparticles of the present invention includes vacuum treatment wherein the particles are suspended in a diluent and subjected to negative pressure to remove unwanted air at the surface of the microparticles. Nonlimiting examples of the negative pressure can be about or less than 300, 200, 100, 150, 145, 143, 90, 89, 88, 87, 86, 85, 75, 50, 35, 34, 33, 32, 31, or 30 Torr for any appropriate time to achieve the desired results, including but not limited to 120, 110, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 8, 5, or 3 minutes.

In certain embodiments, microparticles are stored under negative pressure following the manufacturing and isolation process, wherein negative pressure is defined as any pressure lower than the pressure of ambient room temperature (approximately 760 Torr). In certain embodiments, the microparticles are stored at a pressure of less than about 700 Torr, 550 Torr, 500 Torr, 450 Torr, 400 Torr, 350 Torr, 300 Torr, 250 Torr, 200 Torr, 150 Torr, 100 Torr, 90 Torr, 80 Torr, 60 Torr, 40 Torr, 35 Torr, 32 Torr, 30 Torr, or 25 Torr following the manufacturing and isolation process. In certain embodiments, the microparticles are stored at a pressure of about 500 Torr to about 25 Torr following the manufacturing and isolation process. In certain embodiments, the microparticles are stored at a pressure of about 300 Torr to about 25 Torr following the manufacturing and isolation process. In certain embodiments, the microparticles are stored at a pressure of about 100 Torr to about 25 Torr following the manufacturing and isolation process. In certain embodiments, the microparticles are stored at a pressure of about 90 Torr to about 25 Ton- following the manufacturing and isolation process. In certain embodiments, the microparticles are stored at a pressure of about 50 Torr to about 25 Torr following the manufacturing and isolation process. In certain embodiments, the microparticles are stored at a pressure of about 40 Torr to about 25 Torr following the manufacturing and isolation process. In certain embodiments, the microparticles are stored at a pressure of about 35 Torr to about 25 Torr following the manufacturing and isolation process. In a further embodiment, the microparticles are stored at a temperature of between about 2-8°C at a pressure that is less than about 700, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 80, 60, 50, 40, 35, 32, 30, or 25 Torr.

In certain embodiments, the microparticles are stored at pressure for up to 1 week, 2 weeks,

3 weeks, 4 weeks, 1 month, 2 months, 3 months, 4 months, or more following the manufacture and isolation process. In certain embodiments, the microparticles are stored for up to 1 week to up to

4 weeks at a pressure that is less than 700, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 80, 60, 50, 40, 35, 32, or 30 Torr. In certain embodiments, the microparticles are stored for up to 1 month to up to 2 months at a pressure that is less than 700, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 80, 60, 50, 40, 35, 32, or 30 Torr. In certain embodiments, the microparticles are stored for up to 3 months at a pressure that is less than 700, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 80, 60, 50, 40, 35, 32, or 30 Torr. In certain embodiments, the microparticles are stored at a temperature of between about 2- 8°C following the manufacturing and isolation process and the microparticles are vacuumed less than about 2 hours, 1 hour, 30 minutes, 15 minutes, or 10 minutes prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C following the manufacturing and isolation process and the microparticles are vacuumed 1 hour to 30 minutes prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C following the manufacturing and isolation process and the microparticles are vacuumed 30 minutes to 10 minutes prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C following the manufacturing and isolation process and the microparticles are vacuumed immediately prior to in vivo injection.

In certain embodiments, the microparticles are stored at a temperature of between about 2- 8°C and the microparticles are vacuumed for less than 1 hour, 30 minutes, 20 minutes, 15 minutes, or 10 minutes at a strength of less than about 35 Torr immediately prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C and the microparticles are vacuumed for 1 hour to 30 minutes at a strength of less than about 35 Torr immediately prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C and the microparticles are vacuumed for 30 minutes to 10 minutes at a strength of less than about 35 Torr immediately prior to in vivo injection.

In certain embodiments, the particles are suspended in a glass vial that is attached to a vial adapter and the vial adapter is in turn attached to a VacLok syringe. A negative pressure is created in the vial by pulling the plunger of the syringe into a locking position. In certain embodiments, the vacuum treatment is conducted in a syringe of the 60 mL, 30 mL, 20 mL, or 10 mL size. The vacuum is then held in the syringe with the vial facing up and the large syringe attached for up to at least 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 90 minutes, 100 minutes, or 129 minutes. The vacuum is released, the large syringe is detached, and a syringe is attached for in vivo injection.

In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 143 Torr for about at least 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, or 120 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of at least about 90, 89, 88, 87, 86, or 85 Torr for at least about at 10 minutes, 20 minutes, 30 minutes, or 40 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of at least about 87 Torr for at least about 10 minutes, 20 minutes, 30 minutes, 40 minutes, 60 minutes, 90 minutes, or 120 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of at least about 35, 34, 33, 32, 31, or 30 Torr for at least 5 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of at least about 35, 34, 33, 32, 31, or 30 Torr for at least 8 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of at least about 35, 34, 33, 32, 31, or 30 Torr for at least 10 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of at least about 35, 34, 33, 32, 31, or 30 Torr for at least 20 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of at least about 35, 34, 33, 32, 31, or 30 Torr for at least 30 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of at least about 35, 34, 33, 32, 31, or 30 Torr for at least 40 minutes. In certain embodiments, the particles are subjected to 30 Torr for at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 35 Torr for at least 90 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 35 Torr for at least 60 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 35 Torr for at least 30 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 35 Torr for at least 15 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 35 Torr for at least 5 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 32 Torr for at least 30 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 32 Torr for at least 15 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 32 Torr for at least 5 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 30 Torr for at least 30 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 30 Torr for at least 15 minutes. In certain embodiments, the particles are subjected to vacuum treatment at a strength of about 30 Torr for at least 5 minutes.

In an alternative embodiment, the particles are suspended in a diluent in a vial attached to a vial adapter that is further attached to a 60 mL VacLok syringe containing a plunger wherein the plunger is pulled to the 50 mL mark and locked to create a negative pressure of approximately 30 Torr and the pressure is held for at least about 3, 5, 8, 10, 15, 20, 25, 30, or 35 minutes. In an alternative embodiment, the particles are suspended in a diluent in a vial attached to a vial adapter that is further attached to a 60 mL VacLok syringe containing a plunger wherein the plunger is pulled to the 45 mL mark, locked, and held for at least about 3, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 minutes. In an alternative embodiment, the particles are suspended in a diluent in a vial attached to a vial adapter that is further attached to a 60 mL VacLok syringe containing a plunger wherein the plunger is pulled to the 40 mL mark, locked, and the pressure is held for at least about 3, 5, 8, 10, 15, 20, 25, 30, or 35 minutes. In an alternative embodiment, the particles are suspended in a diluent in a vial attached to a vial adapter that is further attached to a 60 mL VacLok syringe containing a plunger wherein the plunger is pulled to the 35 mL mark, locked, and held for about at least 3, 5, 8, 10, 15, 20, 25, 30, or 35 minutes. In an alternative embodiment, the particles are suspended in a diluent in a vial attached to a vial adapter that is further attached to a 60 mL VacLok syringe containing a plunger wherein the plunger is pulled to the 30 mL mark, locked, and held for at least about 3, 5, 8, 10, 15, 20, 25, 30, or 35 minutes. In an alternative embodiment, the particles are suspended in a diluent in a vial attached to a vial adapter that is further attached to a 60 mL VacLok syringe containing a plunger wherein the plunger is pulled to the 25 mL mark, locked, and held for at least about 3, 5, 8, 10, 15, 20, 25, 30, or 35 minutes.

In certain embodiments, the particles are suspended in a diluent and the suspension is exposed to a pressure of less than 40 Torr for between about 90 minutes and 1 minute, between about 60 minutes and 1 minute, between about 45 minutes and 1 minute, between about 30 minutes and 1 minute, between about 15 minutes and 1 minute, or between about 5 minutes and 1 minute.

In certain embodiments, the particles are suspended in a diluent and the suspension is exposed to a pressure of less than 30 Torr for between about 90 minutes and 1 minute, between about 60 minutes and 1 minute, between about 45 minutes and 1 minute, between about 30 minutes and 1 minute, between about 15 minutes and 1 minute, or between about 5 minutes and 1 minute.

In certain embodiments, the microparticles are suspended in a diluent of 10X Pro Vise- diluted (0.1% HA in PBS) solution. In certain embodiments, the microparticles are suspended in a diluent of 20X-diluted Pro Vise (0.05% HA in PBS). In certain embodiments, the microparticles are suspended in a diluent of 40X-diluted Pro Vise (0.025% HA in PBS). In certain embodiments, the particles are suspended in the diluent at a concentration of 100 mg/mL, 150 mg/mL, 200 mg/mL, 250 mg/mL, 300 mg/mL, 350 mg/mL, 400 mg/mL, 450 mg/mL or 500 mg/mL. In certain embodiments, the particles are suspended in 10X-diluted Pro Vise (0.1% HA in PBS) solution and the suspension has a final concentration of 200 mg/mL. In certain embodiments, the particles are suspended in 10X-diluted Pro Vise (0.1% HA in PBS) solution and the suspension has a final concentration of 400 mg/mL. In certain embodiments, the particles are suspended in a 20X-diluted ProVisc (0.05% HA in PBS) and the suspension has a final concentration of 200 mg/mL. In certain embodiments, the particles are suspended in a 20X-diluted ProVisc (0.05% HA in PBS) and the suspension has a final concentration of 400 mg/mL. In certain embodiments, the particles are suspended in a 40X-diluted ProVisc (0.025% HA in PBS) and the suspension has a concentration of 200 mg/mL. In certain embodiments, the particles are suspended in a 40X-diluted ProVisc (0.025% HA in PBS) and the suspension has a concentration of 400 mg/mL.

The Addition of an Excipient

In certain embodiments, the process for preparing the microparticles of the present invention is the addition of at least one excipient, typically prior to lyophilization that reduces the amount of air adhering to the particles. Particles are suspended in an aqueous solution and sonicated before being flash frozen in -80 °C ethanol and lyophilized overnight. In certain embodiments, the particles are suspended in an aqueous sugar solution that is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15% sugar. In certain embodiments, the sugar is sucrose. In certain embodiments, the sugar is mannitol. In certain embodiments, the sugar is trehalose. In certain embodiments, the sugar is glucose. In certain embodiments, the sugar is selected from arabinose, fucose, mannose, rhamnose, xylose, D-xylose, glucose, fructose, ribose, D-ribose, galactose, dextrose, dextran, lactose, maltodextrin, maltose, glycerol, erythritol, threitol, arabitol, xylitol, ribitol, sorbitol, galactitol, fucitol, iditol, inositol, volemitol, isomalt, maltitol, lactitol, maltotriitol, maltotetraitol, and polyglycitol. In an alternative embodiment, the sugar is selected from aspartame, saccharin, stevia, sucralose, acesulfame potassium, advantame, alitame, neotame, and sucralose. In certain embodiments, the particles are suspended in an aqueous sugar solution that is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15% sucrose. In certain embodiments, the particles are suspended in a 1% sucrose solution. In certain embodiments, the particles are suspended in a 10% sucrose solution. In certain embodiments, the particles are suspended in an aqueous sugar solution that is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15% mannitol. In certain embodiments, the particles are suspended in a 1% mannitol solution. In certain embodiments, the particles are suspended in a 10% mannitol solution. In certain embodiments, the particles are suspended in a 1% trehalose solution. In certain embodiments, the particles are suspended in a 10% trehalose solution. In certain embodiments, the particles are suspended in an aqueous sugar solution that is 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15% trehalose. In an alternative embodiment, the particles are suspended in a small surfactant molecule, including, but not limited to tween 20 or tween 80. In an alternative embodiment, the particles are flash frozen in -80 °C methanol or isopropanol.

Sonication

In certain embodiments, the process for preparing the microparticles of the present invention is sonication wherein particles are suspended in a diluent and the suspension of microparticles is sonicated for at least 30 minutes, at least 25 minutes, at least 20 minutes, at least 15 minutes, at least 10 minutes, at least 8 minutes, at least 5 minutes, or at least 3 minutes. In certain embodiments, the particle solutions are sonicated at a frequency of 40 kHz. In certain embodiments, the particles are suspended in the diluent at a concentration of 100 mg/mL, 150 mg/mL, 200 mg/mL, 250 mg/mL, 300 mg/mL, 350 mg/mL, 400 mg/mL, 450 mg/mL or 500 mg/mL. In certain embodiments, the diluent is hyaluronic acid. In an alternative embodiment, the diluent is selected from hyaluronic acid, hydroxypropyl methylcellulose, chondroitin sulfate, or a blend of at least two diluents selected from hyaluronic acid, hydroxypropyl methylcellulose, and chondroitin sulfate. In an alternative embodiment, the diluent is selected from aacia, tragacanth, alginic acid, carrageenan, locust bean gum, gellan gum, guar gum, gelatin, starch, methylcellulose, sodium carboxymethylcellulose, hydroxyethylcellulose, hydroxypropyl cellulose, Carbopol® homopolymers (acrylic acid crosslinked with allyl sucrose or allyl pentaerythritol), and Carbopol® copolymers (acrylic acid and C10-C30 alkyl acrylate crosslinked with allyl pentaerythritol).

In certain embodiments, a combination of vacuum treatment, the addition of excipients, and sonication can be used following isolation and reconstitution of the microparticles. In certain embodiments, the methods for enhancing wettability are conducted at least 1 hour prior to in vivo injection, at least 45 minutes prior to in vivo injection, at least 30 minutes prior to in vivo injection, at least 25 minutes prior to in vivo injection, at least 20 minutes prior to injection, at least 15 minutes prior to in vivo injection, at least 10 minutes prior to in vivo injection, or at least 5 minutes prior to in vivo injection. In certain embodiments, the vacuum treatment, addition of an excipient, and/or sonication is conducted immediately before in vivo injection. In certain embodiments, the particles are vacuumed at a strength of less than 35 Torr for less than 30 minutes and are immediately injected in vivo. In an alternative embodiment, the particles are vacuumed at a strength of less than 35 Torr for less than 20 minutes and are immediately injected in vivo. In an alternative embodiment, the particles are vacuumed at a strength of less than 35 Torr for less than 15 minutes and are immediately injected in vivo. In an alternative embodiment, the particles are vacuumed at a strength of less than 35 Torr for less than 10 minutes and are immediately injected in vivo.

In certain embodiments, the microparticles are stored at a temperature of between about 2- 8°C following the manufacturing and isolation process and the microparticles are held under negative pressure for about 24, 12, 8, 6, 2 hours, 1 hour, 30 minutes, 15 minutes, or 10 minutes or less prior to in vivo inj ection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C following the manufacturing and isolation process and the microparticles are held under negative pressure 1 hour to 30 minutes prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C following the manufacturing and isolation process and the microparticles are vacuumed 30 minutes to 10 minutes prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C following the manufacturing and isolation process and the microparticles are vacuumed immediately prior to in vivo injection.

In certain embodiments, the microparticles are stored at a temperature of between about 2- 8°C and the microparticles are vacuumed for less than 1 hour, 30 minutes, 20 minutes, 15 minutes, or 10 minutes at a strength of less than about 35 Torr immediately prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C and the microparticles are vacuumed for 1 hour to 30 minutes at a strength of less than about 35 Torr immediately prior to in vivo injection. In certain embodiments, the microparticles are stored at a temperature of between about 2-8°C and the microparticles are vacuumed for 30 minutes to 10 minutes at a strength of less than about 35 Torr immediately prior to in vivo injection. In certain embodiments, the microparticles are stored at negative pressure for up to 1 week, 2 weeks, 3 weeks, 4 weeks, 1 month, 2 months, 3 months, 4 months, or more following the manufacture and isolation process. In certain embodiments, the microparticles are stored for up to 1 week to up to 4 weeks at a negative pressure that is less than 700, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 80, 60, 50, 40, 35, 32, or 30 Torr. In certain embodiments, the microparticles are stored for up to 1 month to up to 2 months at a negative pressure that is less than 700, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 80, 60, 50, 40, 35, 32, or 30 Torr. In certain embodiments, the microparticles are stored for up to 3 months at a negative pressure that is less than 700, 550, 500, 450, 400, 350, 300, 250, 200, 150, 100, 80, 60, 50, 40, 35, 32, or 30 Torr.

Solvent Evaporation

In this method, the drug (or polymer matrix and drug) is dissolved in a volatile organic solvent, such as methylene chloride, acetone, acetonitrile, 2-butanol, 2-butanone, /-butyl alcohol, benzene, chloroform, cyclohexane, 1,2-dichloroethane, diethyl ether, ethanol, ethyl acetate, heptane, hexane, methanol, methyl /er/-butyl ether, pentane, petroleum ether, /.vo-propanol, n- propanol, tetrahydrofuran, or mixtures thereof. The organic solution containing the drug is then suspended in an aqueous solution that contains a surface active agent such as poly(vinyl alcohol). The resulting emulsion is stirred until most of the organic solvent is evaporated, leaving solid microparticles. The resulting microparticles are washed with water and dried overnight in a lyophilizer. Microparticles with different sizes and morphologies can be obtained by this method.

Microparticles which contain labile polymers, such as certain polyanhydrides, may degrade during the fabrication process due to the presence of water. For these polymers, the following two methods, which are performed in completely anhydrous organic solvents, can be used.

Oil-In-Oil Emulsion Technique

Solvent removal can also be used to prepare particles from drugs that are hydrolytically unstable. In this method, the drug (or polymer matrix and drug) is dispersed or dissolved in a volatile organic solvent such as methylene chloride, acetone, acetonitrile, benzene, 2-butanol, 2- butanone, /-butyl alcohol, chloroform, cyclohexane, 1,2-dichloroethane, diethyl ether, ethanol, ethyl acetate, heptane, hexane, methanol, methyl /c/V-butyl ether, pentane, petroleum ether, iso propanol , «-propanol, tetrahydrofuran, or mixtures thereof. This mixture is then suspended by stirring in an organic oil (such as silicon oil, castor oil, paraffin oil, or mineral oil) to form an emulsion. Solid particles form from the emulsion, which can subsequently be isolated from the supernatant. The external morphology of spheres produced with this technique is highly dependent on the identity of the drug.

Oil-In-Water Emulsion Technique

In this method, the drug (or polymer matrix and drug) is dispersed or dissolved in a volatile organic solvent such as methylene chloride, acetone, acetonitrile, benzene, 2-butanol, 2-butanone, /-butyl alcohol, chloroform, cyclohexane, 1,2-dichloroethane, diethyl ether, ethanol, ethyl acetate, heptane, hexane, methanol, methyl /er/-butyl ether, pentane, petroleum ether, /.vo-propanol, n- propanol, tetrahydrofuran, or mixtures thereof. This mixture is then suspended by stirring in an aqueous solution of surface active agent, such as poly(vinyl alcohol), to form an emulsion. Solid particles form from the emulsion, which can subsequently be isolated from the supernatant. The external morphology of spheres produced with this technique is highly dependent on the identity of the drug.

As described in PCT/US2015/065894, microparticles with a therapeutic agent can be prepared using the oil-in-water emulsion method. In one example, sunitinib microparticles were prepared by dissolving 100 mg PEG-PLGA (5K, 45) in 1 mL methylene chloride, and dissolving 20 mg sunitinib malate in 0.5 mL DMSO and triethylamine. The solutions were then mixed together, homogenized at 5000 rpm, 1 minute into an aqueous solution containing 1% polyvinyl alcohol (PVA) and stirred for 2 hours. The particles were collected, washed with double distilled water, and freeze dried. In another example, sunitinib microparticles were also prepared according to PCT/US2015/065894 by dissolving 200 mg PLGA (2A, Alkermers) in 3 mL methylene chloride, and 40 mg sunitinib malate in 0.5 mL DMSO and triethylamine. The solutions were then mixed together and homogenized at 5000 rpm, 1 minute in 1% PVA and stirred for 2 hours. The particles were collected, washed with double distilled water, and freeze dried.

Spray Drying

In this method, the drug (or polymer matrix and drug) is dissolved in an organic solvent such as methylene chloride, acetone, acetonitrile, 2-butanol, 2-butanone, /-butyl alcohol, benzene, chloroform, cyclohexane, 1,2-dichloroethane, diethyl ether, ethanol, ethyl acetate, heptane, hexane, methanol, methyl /er/-butyl ether, pentane, petroleum ether, /.vo-propanol, «-propanol, tetrahydrofuran, or mixtures thereof. The solution is pumped through a micronizing nozzle driven by a flow of compressed gas, and the resulting aerosol is suspended in a heated cyclone of air, allowing the solvent to evaporate from the microdroplets, forming particles. Particles ranging between 0.1-10 microns can be obtained using this method.

Phase Inversion

Particles can be formed from drugs using a phase inversion method. In this method, the drug (or polymer matrix and drug) is dissolved in a solvent, and the solution is poured into a strong non solvent for the drug to spontaneously produce, under favorable conditions, microparticles or nanoparticles. The method can be used to produce nanoparticles in a wide range of sizes, including, for example, about 100 nanometers to about 10 microns, typically possessing a narrow particle size distribution.

Coacervation

Techniques for particle formation using coacervation are known in the art, for example, in GB-B-929 406; GB-B-929 40 1; and U.S. Patent Nos. 3,266,987, 4,794,000, and 4,460,563. Coacervation involves the separation of a drug (or polymer matrix and drug) solution into two immiscible liquid phases. One phase is a dense coacervate phase, which contains a high concentration of the drug, while the second phase contains a low concentration of the drug. Within the dense coacervate phase, the drug forms nanoscale or microscale droplets, which harden into particles. Coacervation may be induced by a temperature change, addition of a non-solvent or addition of a micro-salt (simple coacervation), or by the addition of another polymer thereby forming an interpolymer complex (complex coacervation).

Low Temperature Casting

Methods for very low temperature casting of controlled release microspheres are described in U.S. Patent No. 5,019,400 to Gombotz et al. In this method, the drug (or polymer matrix and sunitinib) is dissolved in a solvent. The mixture is then atomized into a vessel containing a liquid non-solvent at a temperature below the freezing point of the drug solution which freezes the drug droplets. As the droplets and non-solvent for the drug are warmed, the solvent in the droplets thaws and is extracted into the non-solvent, hardening the microspheres. Scale Up

The processes for producing microparticles described in the Examples are amenable to scale up by methods known in the art. Examples of such methods include U.S. Patent 4,822,534; U.S. Patent 5,271,961; U.S. Patent 5,945,126; U.S. Patent 6,270,802; U.S. Patent 6,361,798; U.S. Patent 8,708,159; and U.S. publication 2010/0143479. U.S. Patent 4,822,534 describes a method of manufacture to provide solid microspheres that involves the use of dispersions. These dispersions could be produced industrially and allowed for scale up. U.S. Patent 5,271,961 disclosed the production of protein microspheres which involved the use of low temperatures, usually less than 45 °C. U.S. Patent 5,945,126 describes the method of manufacture to produce microparticles on full production scale while maintaining size uniformity observed in laboratory scale. U.S. Patent 6,270,802 and U.S. Patent 6,361,798 describe the large scale method of manufacture of polymeric microparticles whilst maintaining a sterile field. U.S. Patent 8,708,159 describes the processing of microparticles on scale using a hydrocyclone apparatus. U.S. publication 2010/0143479 describes the method of manufacture of microparticles on large scale specifically for slow release microparticles.

XSpray has disclosed a device and the use of supercritical fluids to produce particles of a size below 10 mM (U.S. Patent 8,167,279). Additional patents to XSpray include U.S. Patent 8,585,942 and U.S. Patent 8,585,943. Sun Pharmaceuticals has disclosed a process for the manufacture of microspheres or microcapsules, WO 2006/123359, herein incorporated by reference. As an example, Process A involves five steps that include 1) the preparation of a first dispersed phase comprising a therapeutically active ingredient, a biodegradable polymer and an organic solvent 2) mixing the first dispersed phase with an aqueous phase to form an emulsion 3) spraying the emulsion into a vessel equipped to remove an organic solvent and 4) passing the resulting microspheres or microcapsules through a first and second screen thereby collecting a fractionated size of the microspheres or microcapsules and 5) drying the microspheres or microcapsules.

Xu, Q. et al. have disclosed the preparation of monodispersed biodegradable polymer microparticles using a microfluidic flow-focusing device (Xu, Q., et al “Preparation of Monodispersed Biodegradable Polymer Microparticles Using a Microfluidic Flow-Focusing Device for Controlled Drug Delivery”, Small, Vol 5(13): 1575-1581, 2009). Duncanson, W.J. et al. have disclosed the use of microfluidic devices to generate microspheres (Duncanson, W.J. et al. “Microfluidic Synthesis of Monodisperse Porous Microspheres with Size-tunable Pores”, Soft Matter, Vol 8, 10636-10640, 2012).

U. S. Patent No. 8,916, 196 to Evonik describes an apparatus and method for the production of emulsion based microparticles that can be used in connection with the present invention.

XII. Manufacture of Implants

Various techniques may be employed to make implants within the scope of the present invention. Useful techniques include phase separation methods, interfacial methods, extrusion methods, including hot melt extrusion, compression methods, molding methods, injection molding methods, heat press methods, 3D printing, and the like.

Choice of the technique, and manipulation of the technique parameters employed to produce the implants can influence the release rates of the drug. Room temperature compression methods can result in an implant with discrete microparticles of drug and polymer interspersed. Extrusion methods can result in implants with a progressively more homogenous dispersion of the drug within a continuous polymer matrix, as the production temperature is increased.

The use of extrusion methods can allow for large-scale manufacture of implants and result in implants with a homogeneous dispersion of the drug within the polymer matrix. When using extrusion methods, the polymers and active agents that are chosen are often stable at temperatures required for manufacturing, usually at least about 50° C. Extrusion methods use temperatures of about 25° C to about 150° C, more preferably about 60° C to about 130° C. Extrusion methods may be used to avoid the need for solvents in manufacturing. An implant may be produced by bringing the temperature to about 60 C° to about 150 C° for drug/polymer mixing, such as about 130 C°, for a time period of about 0 to 1 hour, 0 to 30 minutes, or 5-15 minutes. For example, a time period may be about 10 minutes, preferably about 0 to 5 minutes. The implants are then extruded at a temperature of about 60 C° to about 130 C°, such as about 80 C°. In addition, the implant may be coextruded so that a coating is formed over a core region during the manufacture of the implant.

Different extrusion methods may yield implants with different characteristics, including but not limited to the homogeneity of the dispersion of the active agent within the polymer matrix. For example, using a piston extruder, a single screw extruder, and a twin-screw extruder will generally produce implants with progressively more homogeneous dispersion of the active. When using one extrusion method, extrusion parameters such as temperature, extrusion speed, die geometry, and die surface finish will have an effect on the release profile of the implants produced.

Hot-melt extrusion is used a process wherein a blended composition is heated and/or compressed to a molten (or softened) state and subsequently forced through an orifice, where the extruded product (extrudate) is formed into its final shape, in which it solidifies upon cooling.

Compression methods may be used to make the implants, and typically yield implants with faster release rates than extrusion methods. Compression methods may use pressures of about 50-150 psi, more preferably about 70-80 psi, even more preferably about 76 psi, and use temperatures of about 0 C° to about 65 C°, more preferably about 25 C°. In one embodiment, the temperature is in the range of about 0 C° to about 50 C°, about 0 C° to about 45 C°, about 0 C° to about 35 C°, about 0 C° to about 25 C°, or about 0 C° to about 15 C°.

In certain embodiments, the implants are molded, preferably in polymeric molds. In particular, the implants are made by molding the materials intended to make up the implants in mold cavities. The molds can be polymer-based molds and the mold cavities can be formed into any desired shape and dimension. Uniquely, as the implants and particles are formed in the cavities of the mold, the implants are highly uniform with respect to shape, size, and composition. Due to the consistency among the physical and compositional makeup of each implant of the present pharmaceutical compositions, the pharmaceutical compositions of the present disclosure provide highly uniform release rates and dosing ranges. The methods and materials for fabricating the implants of the present disclosure are further described and disclosed in the U.S. Patent. Nos. 8,518,316; 8,444,907; 8,420,124; 8,268,446; 8,263,129; 8,158,728; 8,128,393; 7,976,759; and U.S. Patent. Application Publication Nos. 2013-0249138, 2013-0241107, 2013-0228950, 2013- 0202729, 2013-0011618, 2013-0256354, 2012-0189728, 2010-0003291, 2009-0165320, 2008- 0131692.

The mold cavities can be formed into various shapes and sizes. For example, the cavities may be shaped as a prism, rectangular prism, triangular prism, pyramid, square pyramid, triangular pyramid, cone, cylinder, torus, or rod. The cavities within a mold may have the same shape or may have different shapes. In certain aspects of the disclosure, the shapes of the implants are a cylinder, rectangular prism, or a rod. In a particular embodiment, the implant is a rod. The mold cavities can be dimensioned from nanometer to micrometer to millimeter dimensions and larger. For certain embodiments of the disclosure, mold cavities are dimensioned in the micrometer and millimeter range.

In one embodiment, a rod mold cavity with dimensions of about 150 to 1200 micrometers in diameter and about 1 to 10 millimeters in length is used to produce implants of the present invention.

In one embodiment, a rod mold cavity with dimensions of about 150 to 1000 micrometers in diameter and about 1 to 10 millimeters in length is used to produce implants of the present invention.

In one embodiment, a rod mold cavity with dimensions of about 250 to 650 micrometers in diameter and about 3 to 10 millimeters in length is used to produce implants of the present invention.

In one embodiment, a rod mold cavity with dimensions of about 300 to 500 micrometers in diameter and about 3 to 8 millimeters in length is used to produce implants of the present invention.

Once manufactured, the implants may remain on an array for storage, or may be harvested immediately for storage and/or utilization. Implants and particles described herein may be fabricated using sterile processes or may be sterilized after fabrication.

In other methods, single implants can be made using polymers with differing release characteristics where separate drug-polymer blends are prepared that are then co-extruded to create implants that contain different areas or regions having different release profiles. The overall drug release profile of these co-extruded implants are different than that of an implant created by initially blending the polymers together and then extruding them. For example, first and second blends of drug or active agent can be created with different polymers and the two blends can be co-axially extruded to create an implant with an inner core region having certain release characteristics and an outer shell region having second, differing release characteristics. Examples

Example 1. Preparation of surface treated microparticles encapsulating Compound A with 15, 30, and 45% Drug Loading

Microparticles containing prodrugs of timolol were formulated using an oil-in-water solvent evaporation microencapsulation method with a modified skid apparatus at a 200 g scale. The dispersed phase was comprised of a polymer blend encompassing PLA 4A (77 wt%), PLGA8515 5A (22 wt%) and PLGA5050-PEG5K (1 wt%) dissolved in methylene chloride (DCM) at a concentration of 260 mg/mL combined with Compound 3 dissolved in dimethyl sulfoxide (DMSO) at a 2: 1 (DCM:DMSO) ratio.

Total drug mass was varied from 15, 30 and 45% by weight. The dispersed phase was mixed by vigorous vortexing and ultrasoni cation in a bath sonicator to ensure complete dissolution and homogenous mixing of the polymers and drug. The aqueous phase consisted of water containing a 0.25 % PVA as a surfactant to stabilize the emulsification. The flow rate for the aqueous phase was set to 3 L/min. The dispersed phase was pumped at a flow rate of 12.5 mL/min and mixed with the continuous phase at 4200 rpms using a Silverson mixer to generate an oil -in water emulsion and disperse the materials as droplets. The droplets were pumped into a reactor chamber and washed 3 times with water at ambient temperature to remove residual solvents. The particle slurry was subsequently surface-treated with the addition of 5 L of a chilled solution containing ethanol and sodium hydroxide and left to react for 30 minutes at 8-11°C. The surface treated particle slurry was then washed 3 times with cold water. Large particles and aggregates were removed using a 50 micron sieve and mannitol was added as a stabilizer (5 wt %). The slurry was filled into vials and lyophilized overnight. Table 1. Surface-Treatment Parameters of Microparticles with 15, 30, and 45% Drug Loading

Example 2. Methods to assess in vitro aggregation

In order to minimize microparticle dispersion within the vitreous space to prevent obscuring the visual axis, it is essential to develop a formulation that is able to quickly form an aggregate upon injection. Herein, various assays were developed to evaluate the relative kinetics and degree of microparticle aggregation for comparison across different batches and different surface treatment conditions. In vitro aggregation testing test tube assay

Microparticles were suspended in a solution of sodium hyaluronate at a concentration of 200 and 400 mg/mL (0.125% and 0.0625% sodium hyaluronate respectively). Microparticles at a volume of 50 pL was injected into a round bottom glass test-tube filled with 8 mL of pre-warmed PBS (37 °C) and incubated at 37 °C for 15 minutes or 2 hours. At 15 minutes or 2 hours, the test- tubes were removed from the incubator, topped up with pre-warmed PBS to a final volume of 12 mL and placed horizontally on a light box. The test-tube was rolled back and forth to displace the depot from the bottom of the test-tube and an image of the depot was acquired. The degree of particle aggregation was assessed qualitatively based on visual inspection of the depot.

Evaluation of the in vitro aggregation of the 15% drug-loaded microparticles (FIG. 1A- FIG. IP) revealed increased EtOH concentration resulted in an increase in the degree of aggregation. At 50% EtOH, the microparticles were undertreated resulting in poor aggregation at 15 minutes incubation (FIG. 1 A-FIG. IB). As the concentration of EtOH increased to 60 and 65%, the aggregation improved significantly resulting in a characteristic spheroid morphology with less noticeable free-floating particles present in the surrounding PBS media (FIG. 1E-FIG. 1H). At 70% EtOH, the microparticles were over-treated resulting in irregular clumps of particle aggregates (FIG. 1M - FIG. IP).

In contrast, the test tube in vitro aggregation for 30% DL batches was optimal with an ethanol concentration of 55% (FIG. 2A-2L). Increasing the ethanol concentration resulted in overtreated microparticles and poor aggregation in PBS (FIG. 21-FIG. 2K).

In vitro aggregation testing mechanical testing of depot hardness

The relative hardness of the microparticle aggregates were evaluated by monitoring the force in grams required to compress the aggregate at 30% strain force using a Texture Analyzer (Stable Micro Systems, UK) equipped with a 5 mm ball probe. Briefly, microparticles were suspended as described previously in sodium hyaluronate solution at a concentration of 200 or 400 mg/mL. The microparticle suspension (400 pL) was injected into a 2 mL HPLC vial filled with 1.8 mL of PBS prewarmed to 37 °C and incubated at 37°C in a water bath. At various timepoints (15 minutes and 2 hours), samples were removed from the water bath and analyzed for hardness using the texture analyzer at a speed of 0.4 mm/s. Table 2. Mechanical testing of aggregate hardness using a texture analyzer

Analysis of the hardness of the depot by texture analyzer (Table 2) revealed that increasing NaOH concentration and drug loading resulted in harder aggregates. Significant increases in the force required to compress the depot was observed for microparticles with 45% drug loading when compared against microparticles with 30 and 15% drug loading. For example, microparticles surface treated with a solution containing 55% EtOH and 2.5 mM NaOH had a hardness score of 43.5 ± 13.4, 5.0 ± 1.9 and 1.7 ± 0.3 g of force at 2 hours incubation for 45%, 30, and 15% drug loading microparticles, respectively. Increasing the drug content within the microparticles resulted in a corresponding decrease in the compressibility of the depot as the drug is embedded within the polymer backbone providing additional structural support.

In vitro aggregation testing flow cell evaluation of liquid shear force on microparticle aggregation The ability of the microparticle aggregates to resist erosion of surface particles or fragmenting into smaller aggregates by liquid shear force was evaluated using a customized flow cell. Briefly, 50 pL of a microparticle suspension at 200 and 400 mg/mL were injected into a modified 1 mL volumetric pipette filled with pre-warmed PBS (37 °C) connected to a pump on one end and a collection reservoir on the other end. The volumetric pipette was incubated for 5 minutes or 10 minutes at 37 °C in an incubator to allow for the particles to aggregate. Post incubation, PBS was flowed through the volumetric pipette at a rate of 15 mL/min for 2 minutes. Displaced microparticles in the flow medium was collected in the reservoir, concentrated to 1 mL by centrifugation at 1200 rpm for 1 minute and analyzed by UV transmittance using a UV/Vis at 650 nm as previously described. Drug content within the collected sample was also analyzed by HPLC using a standard calibration curve.

Qualitative assessment of the effect of the shear force applied on the depot by the relatively high velocity of the fluid enabled quick and easy evaluation of the kinetics of particle aggregation and allows for identification of the lots with the strongest aggregates. As demonstrated in FIG. 3A-FIG. 3H and Table 3, as the fluid is in motion, shear stresses cause weakly associated microparticles near the surface of the depot to be displaced and eluted out. As incubation time increases, the aggregate strengthens, and the effects of the liquid shear force becomes less prominent by 10 minutes. Quantitative analysis of the eluted materials in the collection reservoir by UV transmittance was found to correlate with the qualitative assessment. Weak aggregates resulted in a low % UV transmittance and stronger aggregates exhibited high % UV transmittance scores. At 5 minutes, Lot F, Lot I, and Lot K exhibited significant dispersion of surface particles from the primary depot (FIG. 3A, FIG. 3C, and FIG. 3E). In contrast, by 10 minutes, all 4 lots tested did not exhibit significant visual displacement of particles from the depot due to the fluid shear force (FIG. 3B, FIG. 3D, FIG. 3F, and FIG. 3H).

Table 3. Percent of UV Transmittance after 5 and 10 Minutes of Incubation of Lots 6, 9, 10, and 11

Surface treatment with 55% EtOH and 7.5 mM NaOH (Lot J) resulted in the strongest aggregate by flow cell analysis with strong particle aggregation at both 5 minutes (FIG. 3G) and 10 minutes (FIG. 3H). As shown in FIG. 4A, FIG. 4B, FIG. 5A, and FIG. 5B, increasing the drug loading percentage from 30 to 45% increased the aggregation strength. For 30% DL particles, the UV transmittance percent at 5 minutes was 92.8% (FIG. 4A). For 45% DL particles, the UV transmittance percent at 5 minutes was 96.2% (FIG. 5A). This correlates with the mechanical hardness testing data previously demonstrated.

Table 4. Percent of UV Transmittance after 5 and 10 Minutes of Incubation of Lots 10 and 13

In vitro aggregation testing oscillation assay for evaluation of microparticle aggregation Similar to the flow cell assay, the oscillation assay was developed to assess the aggregation strength of the microparticle depot from its ability to resist dispersion or fragmentation due to the liquid shear forces generated from the turbulence caused by mechanical oscillation at high rpms. Microparticles were suspended at a concentration of 200 mg/mL in 0.125% sodium hyaluronate and 50 pL was injected into a cuvette filled with 2 mL of warm PBS (37 °C). The cuvette was incubated at 37 °C for 0, 5, or 10 minutes. Subsequently, the cuvettes were placed in an orbital shaker (Fisher Scientific, USA) and shaken at 400 rpms for 1 minute. Immediately post shaking, the cuvette was transferred to a UV/vis and analyzed for % UV transmittance as described previously.

As shown in Table 5, this method enabled kinetic evaluation of the aggregation strength at various timepoints from 0 to 10 minutes. At 0 minutes, all lots tested exhibited very poor aggregation resulting in particle dispersion as expected, and the corresponding % UV transmittance was low (<42%). At 5 minutes, Lots F and J formed strong intact aggregates resulting in a very high % UV transmittance whereas Lots I and K still exhibited significant free floating particles in solution that obscured the transmittance of light though the medium. Table 3 shows that Lots F and J are stronger than Lots I and K.

Table 5. Evaluation of aggregation strength by the oscillation assay

Example 3. Preparation of surface-treated microparticles Compound A with 60% Drug Loading

Microparticles containing prodrugs of timolol were formulated using an oil-in-water solvent evaporation microencapsulation method at a 20 g scale. The dispersed phase was comprised of a polymer blend encompassing PLA 4A (77 wt%), PLGA8515 5 A (22 wt %) and PLGA5050-PEG5K (1 wt %) dissolved in methylene chloride (DCM) at a concentration of 100 mg/mL combined with 294.5 mg/mL of Compound 3 dissolved in dimethyl sulfoxide (DMSO) at a 2:1 (DCM:DMSO) ratio.

Total drug mass was 60% by weight. The dispersed phase was mixed by vigorous vortexing and/or ultrasoni cation in a bath sonicator to ensure complete dissolution and homogenous mixing of the polymers and drug. The aqueous phase consisted of water containing a 0.25 % PVA as a surfactant to stabilize the emulsification. The flow rate for the aqueous phase was set to 3 L/min. The dispersed phase was pumped at a flow rate of 12.5 mL/min and mixed with the continuous phase at 3400 rpm using a Silverson mixer to generate an oil-in-water emulsion and disperse the materials as droplets. The droplets were pumped into a reactor chamber and washed 3 times with water at ambient temperature to remove residual solvents. The particle slurry was subsequently split to 5 sub-batches and each sub-batch was surface treated with the addition of 100 mL of a chilled solution containing ethanol and sodium hydroxide and left to react for 30 minutes in ice bath. The surface treated particle slurry was then washed 3 times with cold water. Large particles and aggregates were removed using a 40-micron cell strainer before lyophilization. The five surface treatment conditions for 60% drug loaded microparticles are listed in Table 6.

Table 6. Surface treatment parameters for 60% drug loaded microparticles

Microparticles were suspended in a solution of 0.125% sodium hyaluronate buffer solution at a concentration of 200 mg/mL. Microparticles at a volume of 50 pL was injected into a round bottom glass test-tube filled with 4 mL of pre-warmed PBS (37 °C) and incubated at 37 °C for 15 minutes or 2 hours. At 15 minutes or 2 hours, the test-tubes were removed from the incubator and placed horizontally on a light box. Then the test tube was oscillated at 150 rpm for 1 minute to test the integrity of the depot and strength of the aggregates. An image of depot was acquired before and after oscillation, respectively. The degree of particle aggregation was assessed qualitatively based on visual inspection of the depot.

Evaluation of the in vitro aggregation of the 60% drug-loaded microparticles (FIG. 6A- FIG. 6T) revealed increased EtOH concentration results in an increase on the degree of aggregation. At 30% EtOH, the microparticles were undertreated resulting in full disintegration of depot after oscillation at 15 minutes incubation (FIG. 6R) and partial disintegration at 2 hours (FIG. 6T). As the concentration of EtOH increased to 45% respectively, the aggregation improved as depot became more resistant to the oscillation at 15 minutes (FIG. 6N) and 2 hours (FIG. 6P). At 50% and 55% EtOH, the depot was further improved with well -maintained aggregate after oscillation at 150 rpm for 1 minute (FIG. 6F, FIG. 6H, FIG. 6J, and FIG. 6L). At 70 % EtOH, the microparticles were over-treated as significant floating particles appeared upon inj ection and loose and irregular clumps of particle aggregates formed even before oscillation (FIG. 6B and FIG. 6D).

Example 4. Preparation of surface-treated microparticles containing 100% Compound A

A 100% drug loaded microparticle (without any polymers) was prepared. Prodrug timolol microparticles were formulated using an oil-in-water solvent evaporation microencapsulation method at a 6 g scale. The dispersed phase was dissolved Compound 3 a mixture of DCM and DMSO (2:1 ratio) at 200 mg/mL.

The aqueous phase consisted of water containing a 0.25 % PVA as a surfactant to stabilize the emulsification. The flow rate for the aqueous phase was set to 3 L/min. The dispersed phase was pumped at a flow rate of 12.5 mL/min and mixed with the continuous phase at 3200 rpm using a Silverson mixer to generate an oil-in-water emulsion and disperse the materials as droplets. The droplets were pumped into a reactor chamber and washed 3 times with water at ambient temperature to remove residual solvents. The lyophilized microparticle was further surface treated in ice bath at 30 mg/mL according to the conditions listed in Table 7. The surface treated particle slurry was then washed 3 times with cold water. Large particles and aggregates were removed using a 40 pm cell strainer before lyophilization.

Table 7. Surface treatment parameters for timolol prodrug microparticles

Microparticles were suspended in a solution of 0.125% sodium hyaluronate buffer solution at a concentration of 200 mg/mL. Microparticles at a volume of 50 pL was injected into a round bottom glass test-tube filled with 4 mL of pre-warmed PBS (37 °C) and incubated at 37 °C for 15 minutes or 2 hours. At 15 minute or 2 hours, the test-tubes were removed from the incubator and placed horizontally on a light box. Then the test tube was oscillated at 150 rpm for 1 min to test the integrity of the depot and strength of the aggregates. An image of depot was acquired before and after oscillation, respectively. The degree of particle aggregation was assessed qualitatively based on visual inspection of the depot.

At 70% and 50% of EtOH, timolol prodrug microparticles was severely overtreated so that the microparticle clumped together during the surface treatment experiment. These samples cannot be further processed for in vitro aggregation at these two conditions. At 30% and 10% of EtOH, microparticles maintained dispersed during surface treatment process and thus were further characterized using in vitro aggregation assay (FIG. 7A-FIG. 7F). At 10% EtOH, the microparticles were undertreated resulting in full disintegration of depot after oscillation at both the 15-minute (FIG. 7B) and 2-hour incubation (FIG. 7D). As the concentration of EtOH increased to 30%, the aggregation of prodrug microparticles were much improved as depot were formed and resistant to the oscillation at 15 minutes (FIG. 7F).

Example 5. Preparation of Timolol Prodrug Implant

Solvent Casting into a Water Bath

A rod-like implant of timolol drug was made by solvent casting method in water. PLA and Compound A were added to N-methyl-2-pyrrolidone (NMP) at 2:1 polymer/ API ratio yielding a final solution with solid concentration of 750 mg/mL.

After all the solids were dissolved in NMP, 0.2-0.3 mL of the solution was withdrawn using a 1 mL syringe without needle. Then a 27G needle was attached and completely submerged in water bath before injection. Afterwards, the solution was slowly injected through the needle and into the water. A small bulb was formed on the needle tip and then was pulled to guide the stream away from the needle while continuing to inject NMP solution. A smooth and homogenous string formed. Once injection was complete, the string was detached from the needle, and the string was allowed to remain in water bath for approximately 16 hours (overnight) for the solvent extraction process. After overnight solvent extraction, the string was removed from water bath, air dried and cut to ~1 cm long implant (FIG. 8). The implant was also observed under microscope showing the implant edge was smooth and the diameter of this implant was 196.10 pm, which can potentially be inserted into a 27-gauge needle for administration.

Compression

An implant in the shape of a rectangular prism was cut from a larger pellet made by powder compression method. Using a cylindrical die and a manual pellet press, microparticles formulated with PLA, PLGA, PEG, and Compound A were compressed at approximately 100 bar to form a cylindrical pellet with a diameter of 13 mm (FIG. 9). Smaller implants with widths ranging from 400 to 1000 um, lengths not more than 10 mm, and heights ranging from 400 to 1000 um were then obtained from the non-sintered pellet using a razor blade (FIG. 10).

Compression with sintering

A pellet is made using the compression method above. Subsequently, the cylindrical pellet was placed in a sealed vial and sintered in a heated bath at approximately 60°C for 10 minutes. To evaluate the effect of sintering on the mechanical strength of the pellet, a sintered and a non- sintered pellet was submerged in phosphate-buffered saline pre-heated at 37°C (FIG. 11). Both solutions were then placed on an oscillating rack for 1 minute. The sintering (right pellet in FIG. 11) appeared to improve the mechanical strength of the pellet.

Smaller implants with widths ranging from 400 to 1000 um, lengths not more than 10 mm, and heights ranging from 400 to 1000 um were then obtained from the sintered implant using a razor blade (FIG. 12).

Hot melt extrusion method

Compound A and biodegradable polymer excipients including PLA, PLGA, PLGA-PEG and/or PEG were accurately weighted and premixed in a sealed container by flipping the container plus vortexing. Various polymers and drug loading are listed in Table 8. The resulting powder blend was fed into an extruder (FLAAKE Twin Screw Compounder, Thermo Fisher Scientific), which was pre-heated to a preset temperature (50-80 degree C°) and screw speed (10-300 rpm). The blend was heated in the extruder and recirculated in the extruder chamber through an internal loop channel for a preset time (2-30 minutes). Then the filament was extruded at pre-set screw speed (10-300 rpm) through a die, guided by a conveying belt and cut into the desired length (3- 10 mm) for further testing. Table 8. Composition of formulations in the hot melt extrusion method

Example 6. In vitro Drug Release of Timolol Prodrug Implants made by Extrusion Process

The in vitro release testing was done at 37 °C in PBS buffer with 1% Tween 20. Three quarters of release medium was removed and replenished with fresh medium at each time point. The released drug amount of timolol was quantitated by HPLC.

Impact of implant diameter on in vitro drug release of timolol prodrug implant

Three lots of implant, Lot 1, Lot 2, and Lot 3, were made under the same batch and the diameter of the extrudate was varied by adjusting the speed of conveyor belt. As shown in Table 9, their diameters are 0.29, 0.35 and 0.62 mm, respectively. The in vitro release curve in FIG. 13 demonstrated that the diameter of extrudate has no impact on release rate or duration and these implants could last for 6 months under this in vitro release condition.

Impact of drug loading on in vitro drug release of timolol prodrug implant Four lots of implant, Lot 2, Lot 4, Lot 5, and Lot 6 were made using the same polymer excipient, but the polymer/drug ratio was varied (see Table 9). The drug loadings (DL) of these lots were 45%, 58%, 70% and 90%, respectively. The release profile of these lots (FIG. 14) show that the release rate and duration is slightly affected by the drug loading and the release rate is slightly more linear and durable when DL is higher. Impact of polymer excipient on in vitro drug release of timolol prodrug implant

As shown in Table 9, the polymer excipients in Lot 2, Lot 4. Lot 5, and Lot 6 are different. As shown by comparing the release curve of Lot 4 and Lot 5 with Lot 2, a higher percentage of PLGA-PEG accelerated the release rate after approximately 4 weeks (FIG. 14). As shown by comparing Lot 11 and Lot 12 with Lot 9 (FIG. 15), the introduction of PLGA 50502A accelerates the overall release rate and shortens the duration of the in vitro release of Compound A.

Example 7. Preparation of Dual API (Timolol Prodrug and Timolol Maleate) Implants using Hot Melt Extrusion Method Compound A, micronized timolol maleate (made by manual grinding or jet mill) and biodegradable polymer excipients including PLA, PLGA and/or PLGA-PEG were accurately weighted and premixed in a sealed container by flipping the container plus vortexing. Various polymers and drug loading are listed in the Table 9. The resulting powder blend was fed into an extruder (HAAKE Twin Screw Compounder, Thermo Fisher Scientific), which was pre-heated to a preset temperature (50-110 degree C°) and screw speed (10-300 rpm). The blend was heated in the extruder and recirculated in the extruder chamber through an internal loop channel for a preset time (2-30 minutes). Then the filament was extruded at pre-set screw speed (10-300 rpm) through a die (0.3-0.5 mm in diameter), guided by a conveyor belt and cut into the desired length of 3-10 mm for further testing. Implant composition, diameter and dose are in Table 9. FIG. 16 is an image of an implant that is approximately 6 mm in length and approximately 0.5 mm in diameter shown next to a dime for scale.

Table 9. Composition of dual API implant formulations

Example 8. In vitro Drug Release of Dual API Implants made by Extrusion Process

The in vitro release profile of single API implant us. dual API implant

As shown in the in vitro release profile of timolol prodrug implants (FIG. 13 -FIG. 15), the release profile of timolol prodrug implants is bimodal and the early-stage release within the first month are much slower than the release rate of 2^nd and 3^rd months. As a control, an implant formulation with only micronized timolol maleate at 40 wt% (Lot 13, Table 9) was also made. Lot 13 had a high burst release within a few days due in part to the high solubility of timolol maleate in aqueous medium. Based on the release data of the timolol prodrug implants and the timolol maleate implant, dual API implants were made to study release rates and profiles. As shown in FIG. 17, the release curves of the dual API implants (Lot 14, Lot 15, and Lot 16) were linear, indicating that sustained and controlled release performance can be achieved by dual API implant.

The impact of polymer excipient on the in vitro release of dual API implant

The drug release profile of dual API implants is affected by the polymer excipients besides the API drug loading. For example, Lot 15 and Lot 20 have the same target drug loading, but different polymer composition (see Table 10). Lot 15 contains a significant amount of PLA 4.5A, which degrades much slower than the PLGA 7525 4A in Lot 20 (Lot 20 contains no PLA 4.5A). Lot 20 released drug for about 4 months while Lot 15 released the drug for about 5 months (FIG. 18).

Example 9. The Impact of Polymer Excipients on Physical Properties of Implant

In addition to the release kinetics, the physical properties including thermal and mechanical properties of the implant are also important to implant drug product in terms of handling, manufacturing, and stability. PEG, a non-toxic biocompatible polymer with a low melting point, was introduced in the implant formulation to study its impact on the thermal properties and mechanical properties (Lot 7 and Lot 8 from Table 8). As shown in Table 8, the melting point of these timolol prodrug implants were significantly reduced by adding 2% or 5% of PEG (MW: 3350) and thus the implant was not stable at body temperature or even room temperature.

PEG was also incorporated into the dual API implants (Lot 23, Lot 24, and Lot 25 in Table 10). The dual API implants with 0.5%, 1% and 2% of PEG (MW:3350) were more flexible and less brittle than other formulations without PEG based on qualitative assessment by manual handling.

Example 10. Preparation of Timolol Prodrug Implant using Timolol Prodrug-Loaded Microparticles

Microparticles (6 g, 15%, 30%, 45% or 60% drug loaded microparticle as described in Examples 1 and 3) are accurately weighted and fed into an extruder (HAAKE Twin Screw Compounder, Thermo Fisher Scientific), which is pre-heated to a preset temperature (50-110 ° C) and screw speed (10-300 rpm). The blend is heated in the extruder and recirculated in the extruder chamber through an internal loop channel for a preset time (2-30 minutes). Then the filament is extruded at a pre-set screw speed (10-300 rpm) through a die (0.3-0.5 mm in diameter) guided by a conveyor belt and cut into the desired length of 3-10 mm for further testing.

Example 11. Preparation of Implant using Timolol Prodrug-Loaded Microparticles and Unencapsulated Micronized Timolol Maleate

As described in Example 10, microparticles made from Compound A and biodegradable polymer excipients including PLA, PLGA and/or PLGA-PEG can replace the powder mixture of all the components in Example 1. To make the dual API implant with both timolol prodrug and unencapsulated timolol maleate, microparticles comprising Compound A and unencapsulated micronized timolol maleate are pre-mixed for extrusion as described herein. A mixture of microparticles (6 g, 15%, 30%, 45% or 60% drug loaded microparticle as described in Example 1 and Example 3) and unencapsulated micronized timolol maleate are accurately weighted and premixed by flipping and vortexing. The mixture is fed into an extruder (ELAAKE Twin Screw Compounder, Thermo Fisher Scientific), which is pre-heated to a preset temperature (50-110 °C) and screw speed (10-300 rpm). The blend is heated in the extruder and recirculated in the extruder chamber through an internal loop channel for a preset time (2-30 minutes). The filament is then extruded at a pre-set screw speed (10-300 rpm) through a die (0.3-0.5 mm in diameter) guided by a conveyor belt and cut into the desired length of 3-10 mm for further testing.

Example 12. Microparticle Suspensions comprising Plasticizer

Preparation of microparticle suspension in a diluent incorporating 0.5% benzyl alcohol and subsequent reconstitution of microparticles

The composition of the diluent for the microparticles consisted of hyaluronic acid (0.125%), NaCl (6.53 g/L), KH₂P0₄ (0.23 g/L), Na₂HP0₄ (0.81 g/L), KC1 (0.09 g/L) and benzyl alcohol (0.5%, w/w). The osmolarity of the diluent was 309 mOsm. Diluent was loaded into a 1 mL luer lock syringe attached to a vial adapter. A vial containing the microparticles was attached to the vial adapter and the diluent was transferred from the syringe into the vial. The vial was vortexed for 3 seconds to generate a suspension with a microparticle concentration of 200 mg/mL. The diluent syringe was replaced, and the reconstituted suspension was loaded into the new syringe for injection.

In vitro aggregation testing in PBS

The effect of benzyl alcohol (BA) on particle aggregation was evaluated in vitro using a test-tube aggregation method. Microparticles were reconstituted as described above in diluent containing 0.5% benzyl alcohol and compared to a control group (microparticles reconstituted in diluent without benzyl alcohol). Round bottom glass test-tubes were filled with 8 mL of pre warmed PBS (37 °C) and a 50 uL volume of microparticle suspension was injected into the bottom of the test-tubes and incubated for 0, 5, 10, 15, or 120 minutes. At these selected timepoints, the test-tubes were removed from the incubator, topped with pre-warmed PBS to a final volume of 12 mL and placed horizontally on a light box. The test-tubes were subsequently rolled back and forth to displace the depot from the bottom of the test-tubes and an image of the depot was acquired. The degree of particle aggregation was assessed qualitatively based on visual inspection of the depot.

As shown in FIG. 19, incorporation of benzyl alcohol into the diluent significantly improved the aggregation kinetics of the microparticles. At early timepoints (<15 minutes), formulations without benzyl alcohol exhibited complete dispersal with no incubation time and significant free-floating microparticles at 5 and 10-minute incubation times. In contrast, formulations with benzyl alcohol have complete aggregation with no observable free-floating particles, well-defined boundaries, and spherical morphology by 5 minutes incubation. There was no different between formulations with and without benzyl alcohol at 15 minutes and 2 hour incubation.

Quantitation of depot hardness using a Texture Analyzer

Mechanical testing of the relative hardness of the microparticle depot was conducted using a Texture Analyzer (Stable Micro Systems, UK) equipped with a 5 mm ball probe. The hardness of the depots was assessed by quantifying the force in grams required to compress the aggregate at 30% strain and a speed of 0.4 mm/s. Briefly, microparticles were reconstituted in diluent formulated with/without 0.5% benzyl alcohol (n =4 per group). The microparticle suspension (400 pL) was injected into a 2 mL HPLC vial filled with 1.8 mL of prewarmed PBS (37 °C) and incubated in a 37 °C water bath. At 15 minute and 2-hour incubation timepoints, samples were removed from the water bath and analyzed for hardness using the texture analyzer.

Evaluation of the effect of benzyl alcohol on the relative hardness of the aggregate revealed significant increases in the hardness of the aggregate with the application of benzyl alcohol in the diluent. After 15 minutes of incubation, there was an approximate 4-fold increase in the hardness of the aggregate reconstituted in diluent with 0.5% benzyl alcohol compared to the control. After 2 hours of incubation, a 1.5-fold higher force was required to depress the aggregate with benzyl alcohol compared to the aggregate without benzyl alcohol (Table 10). In one embodiment, the low plasticizer concentration induces an anti-plasticization effect and enhances the rigidity /hardness of the polymer. Table 10. Evaluation of depot hardness using a texture analyzer

Evaluation of aggregation strength in response to high oscillatory shear forces

The strength of the microparticle aggregate was evaluated in relation to its resistance to dispersion due to high liquid shear forces generated by mechanical oscillation at speed. Briefly, a 50 pL microparticle suspension with and without 0.5% benzyl alcohol was injected into a round- bottom test-tube filled with 2 mL of PBS at 37 °C. The test-tube was incubated at 37 °C for 0, 5, or 10 minutes. Subsequently, the test-tubes were placed in an orbital shaker (Fisher Scientific, USA) and shaken at 400 rpms for 1 minute. Immediately post shaking, the test-tube was transferred to a UV/vis and analyzed for % UV transmittance to determine if any free-floating microparticles were displaced from the primary depot.

As shown in Table 11 at the 0- and 5-minute incubation timepoints, aggregation kinetics of microparticle formulations with benzyl alcohol as a plasticizer was significantly faster than with aggregates formulated without benzyl alcohol. In particular at the t=0 minute incubation, aggregates without benzyl alcohol were readily dispersed from the primary aggregate due to the high oscillatory shear forces, resulting in significant free-floating microparticles and a %UV transmittance score of 72. In contrast, even with no incubation period, microparticle aggregates with benzyl alcohol in the diluent exhibited significant resistance to particle shearing from the primary depot, resulting in a relatively high %UV transmittance value of 94.8%. However, after 10 minutes of incubation, there was no significant difference in % UV transmittance for aggregates formulated with or without benzyl alcohol.

Table 11. Evaluation of depot hardness using a texture analyzer

Qualitative evaluation of aggregation strength in an artificial vitreous gel model

In order to better predict microparticle aggregation kinetic and strength in human eyes, an artificial vitreous humor test medium with comparable mechanical and physiological properties was utilized as in vitro evaluation. As such, an artificial vitreous phantom gel was developed for this specific application using hyaluronic acid solution for its viscoelastic potential and PureCol® EZ gel for the mechanical tissue-mimicking properties of vitreous collagen into the test bed.

A 2.5 mL aqueous solution consisting of 0.25% HA and 0.1% PureCol EZ gel in water was slowly transferred into a plastic cuvette and incubated for 40-60 minutes at 37 °C to generate a gel. Microparticles were reconstituted as described previously in a diluent with or without 0.5% benzyl alcohol. A 50 pL volume of particle suspension was injected into the gel at a distance of approximately 6 mm from the bottom of the gel. The cuvette containing the particle aggregate is placed back into the incubator at 37 °C. At predetermined timepoints (0, 5, 10, 15 minutes incubation), the gel is removed from the incubator and the cuvette is carefully filled with 0.5% HA solution resulting in a 2-phase system consisting of a gel phase at the bottom and a viscous aqueous phase at the top of the cuvette. The cuvette is capped ensuring no air bubbles are present in the cuvette. The cuvette is subsequently inverted, and the aggregate is examined as it transitions through the gel phase and into the aqueous phase due to gravitational forces acting on the dense microparticle aggregate. Weak aggregates will shear and disperse as it migrates through the gel and aqueous phases, whereas stronger aggregates are expected to retain its morphology. The microparticle aggregate is then isolated from the aqueous phase and manipulated with tweezers to confirm the strength of the depot.

As illustrated in FIG. 20, external plasticization with benzyl alcohol improves aggregation kinetics and strength in an artificial vitreous test bed at early timepoints. Although the depot remains intact as it migrates through the gel and viscous aqueous phase, the inherent difference between the aggregates are qualitatively demonstrated upon isolation and manipulation with tweezers. Specifically, upon isolation of the depot at t=0 and t=5 minute incubation timepoints, aggregates reconstituted in diluent without benzyl alcohol readily disperses and cannot be picked up using tweezers. In contrast, aggregates reconstituted in the presence of external benzyl alcohol retain their morphology and can be manipulated with tweezers without breaking apart. No significant enhancements in aggregation due to plasticization is observed at t=10 and t=20 minutes. Example 13. In vitro Drug Release of Microparticle Suspension

The in vitro drug release of the microparticle suspended in the benzyl alcohol -containing diluent was studied to determine if 0.5% benzyl alcohol as a plasticizer will negatively impact drug release.

Microparticles were prepared using a continuous, single emulsion oil-in-water solvent evaporation microencapsulation method. Briefly, Resomer® Select 100 DL 4.5A (77 wt %), Resomer® Select 8515 DLG 5.5A (22 wt %) and Resomer® Select 5050 DLG mPEG5000 (1 wt %) were dissolved in methylene chloride (DCM) at a concentration of 260 mg/mL. Compound A was dissolved in DMSO (45 wt % drug/polymer) and added to the polymer solution at a DCM to DMSO ratio of 2:1 under stirring to generate the dispersed phase. The continuous phase was comprised of phosphate buffered saline (pH 7) with 0.2% PVA as a surfactant. Emulsification was achieved by mixing the dispersed phase with the continuous phase using a high-shear homogenizer at 4200 rpm. The microparticles were transferred to an in-process continuous centrifuge to remove small microparticles. The microparticle slurry was washed with water three times at ambient temperature to remove residual solvent and free drug and subsequently suspended in a surface treatment solution containing 5 mM NaOH in 75% ethanol at 5 °C. Post surface treatment, the microparticle suspension is washed with water three times to remove the surface treatment solution and sieved through a 50 pm filter to remove large particles. The concentration of the drug is determined using in-process sampling and the final suspension is adjusted to achieve target concentration. Mannitol (5 wt %) was added as an excipient during vial-filling and the particles were lyophilized.

In vitro drug release kinetics was evaluated using a static-dissolution setup. Briefly microparticles were reconstituted in a diluent containing 0.5% benzyl alcohol or a diluent without benzyl alcohol as described above. A volume containing 10 mg microparticle equivalence were injected into glass scintillation vials containing 4 mL of a release medium comprising PBS and 1% Tween 20 (pH 7.4). Samples were prepared in duplicate. The particles were incubated on an orbital shaker at 150 rpm at 37 °C. At various time points, 3 mL of release media was collected and replaced with fresh media to maintain sink conditions. Collected release samples were frozen and stored at -80 °C until analysis for drug content. The collected samples were filtered through a 0.2 pm syringe filter and analyzed by RP-HPLC.

FIG. 21 illustrates the normalized cumulative release profile for microparticle aggregates with and without 0.5% benzyl alcohol. The release of the drug from the biodegradable polymeric matrices adheres to a typical triphasic profile with a rapid initial burst release phase, followed by a prolonged intermediate phase as the drug diffuses from inner polymer network and concludes with a slower terminal phase precipitated by bulk erosion of the residual polymer matrix. Plasticizers often impact the initial burst release properties. However, as shown in FIG. 21, there is no significant difference in drug release kinetics when benzyl alcohol is used as a plasticizer.

Example 10 and Example 11 demonstrate that external plasticization with benzyl alcohol improves aggregation kinetics and strength at early timepoints using a number of in vitro assays. In addition, external benzyl alcohol does not negatively affect drug release kinetics from the polymeric drug delivery platform. Introduction of 0.5% benzyl alcohol can improve particle aggregation and mitigate the risk of particle dispersion and migration in human vitreous.

This specification has been described with reference to embodiments of the invention. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth herein. Accordingly, the specification is to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.

Claims

What is claimed is:

1. A biodegradable ocular implant comprising a compound of Formula I or a pharmaceutically acceptable salt thereof:

wherein:

R¹ and R² are independently selected from (i) hydrogen and -C(0)R³;

wherein R¹ and R² cannot both be hydrogen;

2. A biodegradable implant comprising timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I or a pharmaceutically acceptable salt thereof:

wherein:

R¹ and R² are independently selected from

(i) hydrogen and -C(0)R³;

wherein R¹ and R² cannot both be hydrogen;

3. The implant of claim 1 or 2, comprising at least one biodegradable polymer.

4. The implant of claim 3, comprising PLA.

5. The implant of claim 3 or 4, comprising PLGA.

6. The implant of any one of claims 3-5, comprising PEG.

7. The implant of claim 3, comprising PLGA and PLGA-PEG.

8. The implant of claim 3, comprising PLGA, PLA, and PLGA-PEG.

9. The implant of any one of claims 1-8, wherein the compound of Formula I or a pharmaceutically acceptable salt thereof comprises at least about 15 weight percent of the implant.

10. The implant of any one of claims 1-8, wherein the compound of Formula I or a pharmaceutically acceptable salt thereof comprises at least about 30 weight percent of the implant.

11. The implant of any one of claims 1-8, wherein the compound of Formula I or a pharmaceutically acceptable salt thereof comprises at least about 42 weight percent of the implant.

12. The implant of any one of claims 1-8, wherein the compound of Formula I or a pharmaceutically acceptable salt thereof comprises at least about 65 weight percent of the implant.

13. The implant of any one of claims 1-8, wherein the compound of Formula I or a pharmaceutically acceptable salt thereof comprises at least about 85 weight percent of the implant.

14. The implant of claim 1, wherein the compound of Formula I or a pharmaceutically acceptable salt thereof comprises about 100 weight percent of the implant.

15. The implant of any one of claims 2-8, wherein timolol or a pharmaceutically acceptable salt thereof and the compound of Formula I or a pharmaceutically acceptable salt thereof comprise at least about 15 weight percent of the implant.

16. The implant of any one of claims 2-8, wherein timolol or a pharmaceutically acceptable salt thereof and the compound of Formula I or a pharmaceutically acceptable salt thereof comprise at least about 30 weight percent of the implant.

17. The implant of any one of claims 2-8, wherein timolol or a pharmaceutically acceptable salt thereof and the compound of Formula I or a pharmaceutically acceptable salt thereof comprise at least about 42 weight percent of the implant.

18. The implant of any one of claims 2-8, wherein timolol or a pharmaceutically acceptable salt thereof and the compound of Formula I or a pharmaceutically acceptable salt thereof comprise at least about 65 weight percent of the implant.

19. The implant of any one of claims 2-8, wherein timolol or a pharmaceutically acceptable salt thereof and the compound of Formula I or a pharmaceutically acceptable salt thereof comprise at least about 85 weight percent of the implant.

20. The implant of claim 2, wherein timolol or a pharmaceutically acceptable salt thereof and the compound of Formula I or a pharmaceutically acceptable salt thereof comprise about 100 weight percent of the implant.

21. The implant of any one of claims 1-20, wherein the implant comprises plasticizer.

22. The implant of claim 21 wherein the plasticizer is benzyl alcohol.

23. The implant of claim 21 wherein the plasticizer is tri ethyl citrate.

24. The implant of any one of claims 1-23, wherein the implant releases the compound of Formula I over a sustained period of at least three months.

25. The implant of any one of claims 1-23, wherein the implant releases the compound of Formula I over a sustained period of at least four months.

26. The implant of any one of claims 1-23, wherein the implant releases the compound of Formula I over a sustained period of at least five months.

27. The implant of any one of claims 1-23, wherein the implant releases the compound of Formula I over a sustained period of at least six months.

28. The implant of any one of claims 2-13 and 15-23, wherein the implant releases timolol and the compound of Formula I over a sustained period of at least three months.

29. The implant of any one of claims 2-13 and 15-23, wherein the implant releases timolol and the compound of Formula I over a sustained period of at least four months.

30. The implant of any one of claims 2-13 and 15-23, wherein the implant releases timolol and the compound of Formula I over a sustained period of at least five months.

31. The implant of any one of claims 2-13 and 15-23, wherein the implant releases timolol and the compound of Formula I over a sustained period of at least six months.

32. The implant of any one of claims 1-31, in the shape of a rod.

33. The implant of claims 32, wherein the rod is at least about 150 pm to about 1200 pm or less in diameter and at least about 1 mm to about 10 mm or less in length.

34. The implant of claim 32, wherein the rod is at least about 300 pm to about 600 pm or less in diameter.

35. The implant of any one of claims 1-34, wherein the rod is at least about 3 to about 8 mm or less in length.

36. The implant of any one of claims 1-31, in the shape of a cylindrical pellet.

37. The implant of claim 36, wherein the cylindrical pellet is at least about 150 pm to about 1200 pm or less in width, at least about 1 mm to about 10 mm or less in length, and at least about 150 pm to about 1200 pm or less in height.

38. The implant of claim 36, wherein the cylindrical pellet is at least about 400 pm to about 1000 pm or less in width, at least about 3 mm to about 10 mm or less in length, and at least about 400 pm to about 1000 pm or less in height.

39. The implant of any one of claims 1, 3-14, 21-27, and 32-38 wherein the implant is formed from (a) microparticles comprising a compound of Formula I or a pharmaceutically acceptable salt thereof and (b) un encapsulated compound of Formula I or a pharmaceutically acceptable salt thereof.

40. The implant of any one of claims 1-38, wherein the implant is formed from (a) microparticles comprising timolol or a pharmaceutically acceptable salt thereof and/or a compound of Formula I or a pharmaceutically acceptable salt thereof and (b) unencapsulated compound of Formula I or a pharmaceutically acceptable salt thereof.

41. The implant of any one of claims 1-38, wherein the implant is formed from (a) microparticles comprising timolol or a pharmaceutically acceptable salt thereof and/or a compound of Formula I or a pharmaceutically acceptable salt thereof and (b) unencapsulated micronized timolol or a pharmaceutically acceptable salt thereof.

42. The implant of any one of claims 1-38, wherein the implant is formed from (a) microparticles comprising timolol or a pharmaceutically acceptable salt thereof and/or a compound of Formula I or a pharmaceutically acceptable salt thereof and (b) unencapsulated micronized timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I or a pharmaceutically acceptable salt thereof.

43. The implants of any one of claims 1-42, wherein the implant exhibits a hardness rating of at least about 5-gram force needed to compress the particle at 30% of stain in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

44. The implant of claim 43, wherein the hardness rating is at least about 15-gram force.

45. The implant of claim 43, wherein the hardness rating is at least about 20-gram force.

46. The implant of claim 43, wherein the hardness rating is at least about 40-gram force.

47. The implant of claim 43, wherein the hardness rating is at least about 60-gram force.

48. The implant of claim 43, wherein the hardness rating is at least about 80-gram force.

49. The implant of claim 43, wherein the hardness rating is at least about 100-gram force.

50. The implant of claim 43, wherein the hardness rating is at least about 150-gram force.

51. The implant of any one of claims 1-50, wherein R¹ and R² are independently selected from

53. The implant of any one of claims 1-50, wherein R¹ and R² are independently selected from

54. The implant of any one of claims 1-50, wherein R¹ is hydrogen and R² is selected from

55. The implant of any one of claims 1-50, wherein R² is hydrogen and R¹ is selected from

56. The implant of any one of claims 51-55, wherein x and y are independently selected from 1, 2, 3, 4, 5, 6, or 7.

57. The implant of any one of claims 51-55, wherein y is 1 and x is selected from 1, 2, 3, or 4.

58. The implant of any one of claims 1-50, wherein the compound of Formula I has the structure selected from

or a pharmaceutically acceptable salt thereof.

59. The implant of any one of claims 1-50, wherein the compound of Formula I has the structure selected from

or a pharmaceutically acceptable salt thereof.

60. The implant of any one of claims 1-50, wherein the compound of Formula I has the structure

or a pharmaceutically acceptable salt thereof.

61. The implant of any one of claims 1-50, wherein the compound of Formula I has the structure

or a pharmaceutically acceptable salt thereof.

62. Solid microparticles for injection in vivo comprising at least about 42% by weight of a drug load of a compound of Formula I:

or a pharmaceutically acceptable salt thereof wherein: R¹ and R² are independently selected from (i) hydrogen and -C(0)R³;

, anu wherein R¹ and R² cannot both be hydrogen;

63. Solid microparticles for injection in vivo comprising timolol or a pharmaceutically acceptable salt thereof and a compound of Formula I:

or a pharmaceutically acceptable salt thereof wherein: R¹ and R² are independently selected from

(i) hydrogen and -C(0)R³;

wherein R¹ and R² cannot both be hydrogen;

64. The microparticles of claim 62 or 63, wherein the microparticles comprise surfactant and wherein the microparticles: (i) have a modified surface which has been treated under mild conditions to partially remove surfactant; and

(ii) aggregate in vivo to form at least one aggregated microparticle depot of at least 500 pm in vivo in a manner that provides sustained drug delivery in vivo for at least one month.

65. The microparticles of claim 62 or 63, wherein the microparticles do not have a modified surface which has been treated under mild conditions and do not aggregate in vivo to least one aggregated microparticle depot of at least 500 pm.

66. The microparticles of any one of claims 62-65, comprising at least one biodegradable polymer.

67. The microparticles of claim 66, comprising at least one hydrophobic polymer and at least one hydrophobic polymer conjugated to a hydrophilic polymer.

68. The microparticles of claim 66 or 67, comprising PLGA.

69. The microparticles of claim 66 or 67, comprising PLA.

70. The microparticles of any one of claims 66-69, comprising PEG.

71. The microparticles of any one of claims 66-70, comprising PLGA-PEG.

72. The microparticles of any one of claims 66-71, comprising PLA-PEG.

73. The microparticles of claim 66, comprising PLGA and PLGA-PEG.

74. The microparticles of claim 66, comprising PLGA, PLA, and PLGA-PEG.

75. The microparticles of any one of claims 62-74, wherein the drug load is about 45 percent by weight or greater.

76. The microparticles of any one of claims 62-74, wherein the drug load is about 60 percent by weight or greater.

77. The microparticles of any one of claims 62-74, wherein the drug load is about 80 percent by weight or greater.

78. The microparticles of any one of claims 62-74, wherein the drug load is about 90 percent by weight or greater.

79. The microparticles of any one of claims 62-74, wherein the drug load is about 100 percent by weight.

80. A suspension of the microparticles of any one of claims 62-64 and 66-79 in a diluent for injection that includes an additive that softens the surface of the microparticle before administration to prepare the microparticles for aggregation.

81. The suspension of claim 80 wherein the additive is a plasticizer. 82. The suspension of claim 81 wherein the plasticizer is benzyl alcohol.

83. The suspension of claim 81 wherein the plasticizer is tri ethyl citrate.

84. The microparticles of any one of claims 62-64 and 66-79, wherein the aggregated microparticle depot exhibits a hardness rating of at least about 5-gram force needed to compress the particle at 30% of stain in vitro in a fluid selected from vitreous, water, phosphate buffered saline, or an aqueous physiologically acceptable solution with a viscosity not more than about 4 times that of water.

85. The microparticles of claim 84, wherein the hardness rating is at least about 15-gram force.

86. The microparticles of claim 84, wherein the hardness rating is at least about 20-gram force.

87. The microparticles of claim 84, wherein the hardness rating is at least about 40-gram force.

88. The microparticles of claim 84, wherein the hardness rating is at least about 60-gram force.

89. The microparticles of claim 84, wherein the hardness rating is at least about 80-gram force.

90. The microparticles of claim 84, wherein the hardness rating is at least about 100-gram force.

91. The microparticles of claim 84, wherein the hardness rating is at least about 150-gram force.

92. The microparticles of any one of claims 62-91, wherein R¹ and R² are independently selected from

93. The microparticles of any one of claims 62-91, wherein R¹ and R² are independently selected from

94. The microparticles of any one of claims 62-91, wherein R¹ and R² are independently selected from

95. The microparticles of any one of claims 62-91, wherein R¹ is hydrogen and R² is selected from

96. The microparticles of any one of claims 62-91, wherein R² is hydrogen and R¹ is selected from

97. The microparticles of any one of claims 62-96, wherein x and y are independently selected from 1, 2, 3, 4, 5, 6, or 7.

98. The microparticles of any one of claims 62-96, wherein x and y are independently selected from 1, 2, 3, or 4.

99. The microparticles of any one of claims 62-96, wherein y is 1 and x is selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

100. The microparticles of any one of claims 62-96, wherein y is 1 and x is selected from 1, 2, 3, or 4.

101. The microparticles of any one of claims 62-91, wherein the compound of Formula I has the structure selected from

or a pharmaceutically acceptable salt thereof.

102. The microparticles of any one of claims 62-91, wherein the compound of Formula I has the structure selected from

or a pharmaceutically acceptable salt thereof.

103. The microparticles of any one of claims 62- 102, wherein the surfactant is polyvinyl alcohol.

104. A method to treat an ocular disorder selected from glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves. In another embodiment more generally, the disorder treated is allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy comprising administering the implants of any one of claims 1-61 in a host in need thereof.

105. A method to treat an ocular disorder selected from glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves. In another embodiment more generally, the disorder treated is allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy comprising administering the microparticles of any one of claims 62-79 and 84-103 or the suspension of microparticles of any one of claims 80-83 in a host in need thereof.

106. The method of claim 104 or 105 wherein the disorder is glaucoma.

107. The method of claim 106, wherein the glaucoma is primary open angle glaucoma.

108. The method of any one of claims 104-107, wherein the host is a human.

109. The microparticles of any one of claims 62-79 and 84-103 or the suspension of microparticles of any one of claims 80-83 for use to treat an ocular disorder in a host in need thereof wherein the ocular disorder is selected from glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves. In another embodiment more generally, the disorder treated is allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy.

110. An implant of any one of claims 1-61 for use to treat an ocular disorder in a host in need thereof wherein the ocular disorder is selected from glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves. In another embodiment more generally, the disorder treated is allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy.

111. The use of microparticles of any one of claims 62-79 and 84-103 or the suspension of microparticles of any one of claims 80-83 in the manufacture of a medicament for the treatment of an ocular disorder in a host in need thereof wherein the ocular disorder is selected from glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves. In another embodiment more generally, the disorder treated is allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy.

112. The use of an implant of any one of claims 1-61 in the manufacture of a medicament for the treatment of an ocular disorder in a host in need thereof wherein the ocular disorder is selected from glaucoma, a disorder or abnormality related to an increase in intraocular pressure (IOP), a disorder mediated by nitric oxide synthase (NOS), or a disorder requiring neuroprotection such as to regenerate/repair optic nerves. In another embodiment more generally, the disorder treated is allergic conjunctivitis, anterior uveitis, cataracts, wet or dry age-related macular degeneration, neovascular age-related macular degeneration, or diabetic retinopathy.