WO2018194918A1

WO2018194918A1 - Coating systems on plastic substrates that inhibit free radical-induced degradation of biologics in primary packaging

Info

Publication number: WO2018194918A1
Application number: PCT/US2018/027452
Authority: WO
Inventors: Christopher Weikart; Steven Martin; Jason Armstrong
Original assignee: Sio2 Medical Products, Inc.
Priority date: 2017-04-14
Filing date: 2018-04-13
Publication date: 2018-10-25

Abstract

A method for preventing or reducing reaction of radiation sterilization-generated free radicals and/or byproducts thereof and/or oxygen with contents of a primary vessel is provided. A radiation sterilized primary plastic vessel contains contents prone to degradation by free radicals and/or byproducts thereof and/or oxygen. The vessel has a coating set deposited on an inner wall. The coating set is effective to protect the contents from degradation by radiation sterilization-generated free radicals and/or byproducts thereof and/or oxygen located in the plastic of the vessel and/or on the inner wall.

Description

DOCKET NO. SIO-0087PC PATENT

COATING SYSTEMS ON PLASTIC SUBSTRATES THAT INHIBIT FREE RADICAL-INDUCED DEGRADATION OF BIOLOGICS IN PRIMARY PACKAGING

[0001] Priority is claimed to U.S. Provisional Application No. 62/485,417, filed April 14,

2017, which is incorporated herein by reference in its entirety.

[0002] The specification and drawings of U.S. Patent No. 7,985,188, Issued July 26, 2011 and International Application Nos. PCT/US2016/047622, filed August 18, 2016 and PCT/US2014/023813, filed March 11, 2014 are incorporated herein by reference in their entirety.

FIELD OF INVENTION

[0003] The invention relates generally to coatings for plastic vessels that inhibit the effects of radiation sterilization-generated free radicals on biologies and other materials in contact with such vessels.

BACKGROUND

[0004] Primary packaging for pharmaceutical, biological and diagnostic products is typically made from glass or plastic. Traditional glass pharmaceutical packages or other vessels are prone to breakage or degradation during manufacture, filling operations, shipping and use, which means that glass particulates may enter the drug or other contents. As a result, some companies have turned to plastic primary pharmaceutical packages or other vessels, which provide greater dimensional tolerance and less breakage than glass, but its use for primary pharmaceutical packaging remains limited due to its gas (oxygen) permeability.

[0005] Additional challenges to using plastic primary containers for pharmaceutical, biological and diagnostic products include the ability to sterilize such containers without: (1) exposing the containers to particulate contamination (e.g., from gas sterilization); and (2) producing potentially drug-degrading free radicals (e.g., from radiation sterilization) and allowing oxygen ingress.

[0006] Conventional methods for sterilizing primary packaging include steam or gas (e.g., ethylene oxide) sterilization and radiation sterilization (e.g., electron beam ("e beam"), x-ray or gamma ray). Ethylene oxide ("EO") sterilization (and other types of gas sterilization methods) requires gas permeability of the secondary packaging retaining the primary containers during sterilization. Tyvek®, a material produced by DuPont, is gas permeable and is typically used in DOCKET NO. SIO-0087PC PATENT secondary packaging for gas sterilization of primary containers. Tyvek® comprises a mesh of plastic fibers that are tightly bonded together to act as an air filter. Tyvek® allows sterilizing gas to permeate into the secondary packaging (and, in turn, into the primary container(s) retained therein) to sterilize the primary container(s). While Tyvek® is efficient and effective for this type of sterilization, its construction inherently renders it a source for particulate contamination of the primary container(s).

[0007] Radiation sterilization does not require gas permeable secondary packaging for retaining primary containers undergoing sterilization. Thus, Tyvek® and its risk of particulate contamination, is removed from the equation. However, radiation sterilization of plastic primary containers is the source of another problem - generation of free radicals in the plastic, which may lead to degradation of products held by such containers. Koji Nakamura, et. al, A Strategy for the Prevention of Protein Oxidation by Drug Product in Polymer-Based Syringes, PDA J Pharm Sci and Tech 2015, 69 88-95, (hereinafter "Nakamura 2015"), which is incorporated herein by reference in its entirety, reports that free radicals created during radiation sterilization can contribute to oxidation and degradation of drug products stored in a primary container. Nakamura 2015 identifies the root causes of protein oxidation in biologic drugs as dissolved oxygen within the drug product and the effect from free radicals generated within the container by radiation sterilization. As a solution to these problems, Nakamura 2015 suggests combining the use of an oxygen absorbing material within secondary packaging as a deoxygenated packaging system and using steam sterilization (instead of radiation) to minimize protein oxidation and other negative effects of free radicals on the contents of sterilized primary containers.

[0008] Nakamura 2015' s proposed solution, however, does not resolve the particulate contamination problem, as Tyvek® or the like would need to be used to provide gas permeable secondary packaging during steam sterilization. Further, incorporation of oxygen absorbing material in the secondary packaging introduces an additional component and thus additional complexity to the sterilization system. For some applications, radiation sterilization (particularly e beam sterilization in the pharmaceutical industry) would be a preferred method of sterilization, but for the problems associated with free radicals and oxygen generated thereby.

[0009] Therefore, typical plastic containers are not susceptible to some of the drawbacks of glass containers, but suffer from higher gas permeability and a propensity for sterilization-induced DOCKET NO. SIO-0087PC PATENT radical generation. This heightens the risk of oxidative damage to sensitive drugs. Oxidation is a particularly important type of chemical degradation for protein and peptide APIs, as it is intimately related to protein structure and therefore function. Compared to other chemical degradation pathways such as deamidation, formulation options for controlling oxidation are limited due to the diversity of oxidation pathways.

[0010] Antioxidants such as ascorbate are effective at scavenging radicals and reactive oxygen species (ROS), but often function in a limited pH range, can increase the reactivity of metal ions, and can generate unwelcome chemical changes (e.g. reduction in pH due to metabisulfite oxidation). Decreasing the storage temperature can actually increase oxidation rate due to increased solubility of oxygen in water. Lyophilization can be effective in preventing oxidation of some active pharmaceutical ingredients (APIs), but not all, and is not suitable for many APIs and applications (e.g. prefilled syringes). In order to effectively reduce the oxidative damage to the contents in the vessel, it is important to minimize oxygen inside the storage container. However keeping oxygen out of a drug container over extended storage periods imposes strict requirements on the materials used for packaging.

[0011 ] Advanced plastics such as cyclic olefin polymers (COP) and copolymers (COC) solve many of the problems of glass, but come with their own set of drawbacks. COP and COC are optically clear, with good strength and resistance to fracture and spallation. They have low surface energy, which minimizes API adsorption without siliconization, and can be produced with excellent dimensional tolerances. Importantly, they are non-reactive over a large range of pH values and do not delaminate. COP and COC exhibit low leaching of ions, but organic molecules such as plasticizers and antioxidants can be extracted. While COC and COP provide a good barrier against moisture, they are permeable to gases. This makes them unsuited to applications requiring low oxygen levels unless accompanied by an airtight secondary packaging system and secondary oxygen scavenger. Another concern is radical generation during sterilization; Nakamura et al found that gamma irradiation at doses typical for sterilization (25 and 50 kGy) produced significant oxidation of the biomolecules in COP syringe barrels, and that erythropoietin(EPO) stored in gamma- sterilized COP syringes oxidized significantly faster than did EPO in steam-sterilized syringes. They ascribe this to free radicals generated by the irradiation process, which presumably diffuse to the inner surface of the barrel and react with the dissolved API. DOCKET NO. SIO-0087PC PATENT

[0012] Therefore there was a need for a plastic vessel which minimizes the oxygen permeation and blocks irradiation-induced free radicals from contacting the contents inside the vessel.

SUMMARY

[0013 ] The current invention solves the above problem by providing an irradiation sterilized vessel coated with PECVD coating set which minimizes oxygen permeation and/or blocks free radicals from contacting the contents inside the vessel. The vessel of the current invention is comparable to glass vessel on oxygen barrier properties and comparable to glass or unsterilized plastic vessel on sterilization-induced free radical level.

[0014] Accordingly, in one aspect, an irradiation sterilized plastic primary container is provided. The container contains an active biomolecule-containing product. The container has an inner wall with a coating set deposited on it. The outermost of the coating set provides a contacting surface with the product, wherein the product held in the container is preserved against degradation from radiation-generated free radicals and/or their byproducts to a greater degree than a reference product held in an uncoated reference container that is otherwise structurally identical in all material respects to the plastic primary container. The coating set may comprise:

• a tie coating or layer of SiOxCy, wherein x is from about 0.5 to about 2.4 and y is from about 0.6 to about 3, on the interior surface of the wall; and/or

• a barrier coating or layer of SiOx, wherein x is from 1.5 to 2.9, on the interior surface of the wall, or when present, the tie coating or layer of SiOxCy; and/or

• a passivation layer or pH protective coating of SiOxCy or SiNxCy, wherein x is from about 0.5 to about 2.4 and y is from about 0.6 to about 3, on the interior surface of the wall or, when present, the barrier coating or layer of SiOx; and/or

• a surface layer or coating of any of, or combination of, the following:

• silicon-based barrier coating system;

• amorphous carbon coating; DOCKET NO. SIO-0087PC PATENT

• fluorocarbon coating;

• direct fluorination;

• antiscratch/antistatic coating;

• antistatic coating;

• antistatic additive compound in polymer;

• oxygen scavenging additive compound in polymer;

• colorant additive compound in polymer;

• or antioxidation additive compound in polymer;

or any combination of the foregoing.

[0015] In another aspect, an alternative irradiation sterilized plastic primary container is provided. The container contains an active biomolecule-containing product which is prone to degradation caused by free radicals and oxygen. The container has an inner wall with a coating set deposited on it. The outermost of the coating set provides a contacting surface with the product, wherein the product held in the container is preserved against degradation from radiation-generated free radicals and/or their byproducts for the shelf-life of the product. The shelf-life is optionally from six months to five years, optionally 6 months, optionally 12 months, optionally 18 months, optionally 24 months, optionally three years, optionally four years, optionally five years. The coating set may be a tie coating, a barrier coating, a pH protective coating, a trilayer coating set or a surface coating, or any combination of one or more of the foregoing.

[0016] In another aspect, an alternative irradiation sterilized vessel is provided. The vessel comprises a plastic substrate with a trilayer coating set deposited thereon. Optionally, the surface of the substrate has free radicals and/or byproducts thereof located thereon which were created by radiation sterilization. The trilayer coating set provides a barrier to the free radicals and/or byproducts, effectively preventing or reducing migration of the free radicals and/or byproducts from the surface of the substrate and/or within the plastic, across the trilayer coating set. The trilayer coating also provides oxygen barrier properties . Optionally, the vessel is a primary container having a product containing space. The trilayer coating set effectively prevents or reduces migration of the free radicals and/or byproducts from the surface of the substrate and/or within the plastic into the product containing space. Optionally, the vessel holds contents prone to degradation by free radicals DOCKET NO. SIO-0087PC PATENT and/or by products thereof. The trilayer coating set is effective in protecting the contents from degradation by radiation sterilization-generated free radicals and/or oxygen.

[0017] In another aspect, a method for preventing or reducing migration of free radicals and/or byproducts thereof from a surface of a plastic substrate of a primary container into a product- containing space of the container and also reducing oxygen ingress into the product-containing space of the container is provided. The method includes providing a radiation sterilized primary plastic container having a coating set deposited on an inner wall of the container. The coating set are effective to prevent or reduce migration of the free radicals and/or byproducts from the surface of the substrate into the product containing space and also reduce oxygen permeation.

[0018] In another aspect, a method for preventing or reducing reaction of radiation sterilization-generated free radicals and/or byproducts thereof with contents of a primary container is provided. The method includes providing a radiation sterilized primary plastic container. The container holds contents prone to degradation by free radicals and/or byproducts thereof. The container includes a coating set deposited on an inner wall thereof. The coating set are effective to protect the contents from degradation by radiation sterilization-generated free radicals and/or byproducts thereof located in the plastic of the vessel and/or on the inner wall. Optionally, the coating set may be a tie coating, a barrier coating, a pH protective coating, a trilayer coating set or any combination of one or more of the foregoing.

[0019] In another aspect, a method of sterilizing a vessel is provided. The method includes providing a plastic vessel having a coating set deposited on a wall thereof and exposing the vessel to sufficient ionizing radiation to sterilize the vessel. The method generates free radicals and/or byproducts thereof located in the plastic of the vessel and/or on the inner wall. There are no such free radicals and/or byproducts thereof or comparatively significantly less on an outermost surface of the coating set than are present on the inner wall.

[0020] It is found that the trilayer coating of the current invention decreases oxygen permeation through the coated COP vial walls when compared to oxygen permeation through uncoated COP vial walls. In at least one embodiment of the current invention, the oxygen permeation through the coated COP vial walls is decreased 33-fold compared to the oxygen permeation of uncoated COP vial walls. Accordingly, the coated COP walls should allow for improved control of oxygen levels in sensitive formulations. DOCKET NO. SIO-0087PC PATENT

[0021 ] It is also found that the two exemplary biomolecules, teriparatide and erythropoietin, stored in the trilayer coating coated vessels did not show elevated susceptibility to oxidation compared to either glass or unsterilized controls.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will be described in conjunction with the following drawings in which like reference numerals designate like elements and wherein:

[0023] Fig. 1 illustrates a sectional view of a coated plastic vial according to an embodiment of the invention.

[0024] Fig. 1A is an enlarged sectional view of the inner surface of the vial of Fig. 1, comprising a trilayer coating set disposed thereon.

[0025] Fig. 2 shows the results of Example 2 comparing the oxidative degradation of glass, uncoated cyclic olefin polymer (COP), and COP (6ml) vials coated with the Applicant's barrier system (i.e. tri-layer) coating technology (as discussed in this specification), filled with a teriparatide drug formulation and sterilized by both gamma and e-beam, then incubated for up to 10 weeks.

[0026] Fig. 3 shows the results of Example 3 comparing the oxidative degradation of glass, uncoated cyclic olefin polymer (COP), and COP (6ml) vials coated with the Applicant's barrier system (i.e. tri-layer) coating technology (as discussed in this specification), filled with a teriparatide drug formulation and sterilized by both gamma and e-beam, then incubated for up to 24 weeks.

[0027] Fig. 4A is a schematic view of the trilayer coating according to one embodiment.

[0028] Fig. 4B presents oxygen permeation data for a trilayer coated COP vial and an uncoated COP vial.

[0029] Fig. 5 illustrates sterilization effects on erythropoietin oxidation.

[0030] Fig. 5A is HPLC spectra of native erythropoietin and H202 oxidized erythropoietin.

[0031] Fig. 5B shows the oxidation peaks of erythropoietin in a trilayer coated COP vial stored for 25 weeks after E-beam, Gamma irradiation versus the oxidation peaks of erythropoietin in an unsterilized COP vial stored for 25 weeks. DOCKET NO. SIO-0087PC PATENT

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Definitions

[0032] For purposes of the present invention, an "organosilicon precursor" is a compound having at least one of the linkages:

— O— Si— C— H or

— NH— Si— C— H which is a tetravalent silicon atom connected to an oxygen or nitrogen atom and an organic carbon atom (an organic carbon atom being a carbon atom bonded to at least one hydrogen atom). A volatile organosilicon precursor, defined as such a precursor that can be supplied as a vapor in a plasma enhanced chemical vapor deposition (PECVD) apparatus, is an optional organosilicon precursor. Optionally, the organosilicon precursor is selected from the group consisting of a linear siloxane, a monocyclic siloxane, a polycyclic siloxane, a polysilsesquioxane, an alkyl trimethoxysilane, a linear silazane, a monocyclic silazane, a polycyclic silazane, a polysilsesquiazane, and a combination of any two or more of these precursors.

[0033] Values of w, x, y, and z are applicable to the empirical composition Si_wOxCyH_z throughout this specification. The values of w, x, y, and z used throughout this specification should be understood as ratios or an empirical formula (for example for a coating or layer), rather than as a limit on the number or type of atoms in a molecule. For example, octamethylcyclotetrasiloxane, which has the molecular composition S14O4C8H24, can be described by the following empirical formula, arrived at by dividing each of w, x, y, and z in the molecular formula by 4, the largest common factor: SiiOiC₂H6. The values of w, x, y, and z are also not limited to integers. For example, (acyclic) octamethyltrisiloxane, molecular composition S13O2C8H24, is reducible to Si1O0.67C2.67H8. Also, although SiO_xC_yH_z is described as equivalent to SiO_xC_y, it is not necessary to show the presence of hydrogen in any proportion to show the presence of SiO_xC_y. DOCKET NO. SIO-0087PC PATENT

[0034] The term "byproducts", when used in the context of byproducts of free radicals, may include products of the reaction of oxygen with free radicals.

[0035] The term "syringe" is broadly defined to include cartridges, injection "pens," and other types of barrels or reservoirs adapted to be assembled with one or more other components to provide a functional syringe. "Syringe" is also broadly defined to include related articles such as auto-injectors, which provide a mechanism for dispensing the contents. Optionally, "syringe" may include pre-filled syringes.

[0036] A "coating set" can be either one coating or multiple coatings. For example, a coating set can comprise just a barrier coating, or it can also comprise a combination of a tie coating, a barrier coating and a pH protective coating. Furthermore, the coating set could be any combination of one or more coatings individually or together.

[0037] The terms "primary packaging" and "primary container", as used in this specification are interchangeable, and are broadly defined as any container or vessel adapted to contain a product or specimen, including but not limited to a drug or biologic. For example, primary packaging may include a syringe, vial, blood tube and the like.

[0038] The term "vessel" be any type of article that is adapted to contain or convey a material. The material can be a liquid, a gas, a solid, or any two or more of these. A primary container, for example, is a type of vessel, of which there are many subtypes. One example of a vessel is an article with at least one opening and a wall defining an interior contacting surface. The term "at least" in the context of the present invention means "equal or more" than the integer following the term. Thus, a vessel in the context of the present invention has one or more openings. The terms "vessel" and "container" are interchangeable.

[0039] One or two openings, like the openings of a sample tube or vial (one opening) or a syringe barrel (two openings) are preferred. If the vessel has two or more openings, they can be of same or different size.

[0040] A vessel according to the present invention can be a sample tube, e.g. for collecting or storing biological fluids like blood or urine, a syringe (or a part thereof, for example a syringe barrel) for storing or delivering a biologically active compound or composition, e.g., a medicament or DOCKET NO. SIO-0087PC PATENT pharmaceutical composition, a vial for storing biological materials or biologically active compounds or compositions, a pipe, e.g., a catheter for transporting biological materials or biologically active compounds or compositions, or a cuvette for holding fluids, e.g., for holding biological materials or biologically active compounds or compositions.

[0041] A vessel can be of any shape. One example of a vessel has a substantially cylindrical wall adjacent to at least one of its open ends. Generally, the interior wall of a vessel of this type is cylindrically shaped, like, e.g. in a sample tube or a syringe barrel. Sample tubes and syringes or their parts (for example syringe barrels), vials, and petri dishes, which commonly are generally cylindrical, are contemplated.

[0042] Some other non-limiting examples of contemplated vessels include well or non-well slides or plates, for example titer plates or microtiter plates. Other examples of vessels include measuring and delivery devices such as pipettes, pipette tips, Erlenmeyer flasks, beakers, and graduated cylinders.

[0043] The invention further has application to any contacting surfaces of devices used or usable in contact with pharmaceutical preparations or other materials, such as ampoules, vials, syringes, bottles, bags, or other containment vessels, stirring rods, impellers, stirring pellets, etc.

[0044] The invention further has application to any contacting surfaces of devices used or usable in contact with biomolecules or solutions of biomolecules, such as ampoules, vials, syringes, bottles, bags, or other containment vessels, stirring rods, impellers, stirring pellets, etc.

[0045] Some specific medical devices and laboratory ware having fluid or tissue contacting surfaces that can be made and used according to the present disclosure follow: agar petri dishes; blood culture devices; blood sample cassettes; blood sampling systems; bottles; capillary blood collection devices; catheters; cell lifters; cell scrapers; cell spreaders; centrifuge components; collection and transport devices; containers; cover glasses; cryo/freezer boxes; depression microscopic slides; direct testing and serology devices; flat microscopic slides; microbiology equipment and supplies; microbiology testing devices; microscopic slides; molecular diagnostics devices; petri dishes; pipettes; pipette tips; sample collection containers; sample collection tubes; sample collection/storage devices; shaker flasks; Erlenmeyer flasks; beakers; graduated cylinders; and syringes. DOCKET NO. SIO-0087PC PATENT

[0046] Though the invention is not necessarily limited to vessels of a particular volume, vessels are contemplated in which the lumen has a void volume of, for example, from 0.5 to 50 mL, optionally from 1 to 10 mL, optionally from 0.5 to 5 mL, optionally from 1 to 3 mL. The substrate surface can be part or all of the inner surface of a vessel having at least one opening and an inner surface.

[0047] "PECVD" refers to plasma enhanced chemical vapor deposition.

[0048] Optionally, vessels according to any embodiment of the present invention may be made from one or more injection moldable thermoplastic materials including, but not limited to: an olefin polymer; polypropylene (PP); polyethylene (PE); cyclic olefin copolymer (COC); cyclic olefin polymer (COP); polymethylpentene; polyester; polyethylene terephthalate; polyethylene naphthalate; polybutylene terephthalate (PBT); PVdC (polyvinylidene chloride); polyvinyl chloride (PVC); polycarbonate; polymethylmethacrylate; polylactic acid; polylactic acid; polystyrene; hydrogenated polystyrene; poly(cyclohexylethylene) (PCHE); epoxy resin; nylon; polyurethane polyacrylonitrile; polyacrylonitrile (PAN); an ionomeric resin; Surlyn® ionomeric resin. For applications in which clear and glass-like polymers are desired (e.g., for syringes and vials), a cyclic olefin polymer (COP), cyclic olefin copolymer (COC) or polycarbonate may be preferred. Such materials may be manufactured, e.g., by injection molding or injection stretch blow molding, to very tight and precise tolerances (generally much tighter than achievable with glass).

Coated Vessels

[0049] As an aspect of the present invention, it may be desired to provide a coating set to the interior wall of a plastic primary container (or other vessels) to modify the properties of that container. For example, the coating set may improve the barrier properties of the container and prevent interaction between the container wall (or an underlying coating) and drug product held within the container.

[0050] Another aspect of the present invention is an irradiation sterilized plastic primary vessel comprising an active biomolecule-containing contents therein, the vessel having an inner wall with a coating set deposited thereon, the outermost of the coating set providing a contacting surface with the product, wherein the product held in the vessel is preserved against degradation to a greater degree than a reference product held in an uncoated reference vessel that is otherwise structurally identical in all material respects to the plastic primary vessel, wherein the coating set comprises: DOCKET NO. SIO-0087PC PATENT

• a surface layer or coating of any of, or combination of, the following:

• silicon-based barrier coating system;

• amorphous carbon coating;

• fluorocarbon coating;

• direct fluorination;

• antiscratch/antistatic coating;

• antistatic coating;

• antistatic additive compound in polymer;

• oxygen scavenging additive compound in polymer;

• colorant additive compound in polymer;

• or antioxidation additive compound in polymer;

or combination of, and any combination of the foregoing.

[0051] The degradation of the contents in the sterilized vessels can be caused by either radiation-generated free radicals or oxygen gas or both.

[0052] A vial 10 according to an aspect of the present invention is shown in Fig. 1. The vial

10 is made from an injection moldable thermoplastic material such as any of those described in this specification. Preferably, the vial is made from cyclic olefin polymer (COP), although other plastics may be preferred depending on the application. The vial has a sidewall 14 enclosing a product- containing space 12. DOCKET NO. SIO-0087PC PATENT

[0053] Fig. 1A is an enlarged sectional view of the vial 10. The internal surface 16 of the sidewall 14 of the vial 10 may include a coating set 100 comprising one or more coatings or layers. As shown, the internal surface 16 of the sidewall 14 may include at least one tie coating or layer 102, at least one barrier coating or layer 104, and at least one organo-siloxane coating or layer 106. The organo-siloxane coating or layer 106 preferably has pH protective properties. This embodiment of the coating set 100 is referred to herein as a "trilayer coating set" in which the barrier coating or layer 104 of SiOx is protected against contents having a pH otherwise high enough to remove it by being sandwiched between the pH protective organo-siloxane coating or layer 106 and the tie coating or layer 102. Aspects of the trilayer coating set are described in Applicant's U.S. Pat. Pub. No. 2014/0251859, which is incorporated by reference herein in its entirety. The contemplated thicknesses of the respective layers in nm (preferred ranges in parentheses) are given in the following Trilayer Thickness Table:

[0054] Properties and compositions of each of the coatings that make up the trilayer coating set are now described.

[0055] The tie coating or layer 102 has at least two functions. One function of the tie coating or layer 102 is to improve adhesion of a barrier coating or layer 104 to a substrate (e.g., the internal surface 16 of the sidewall 14), in particular a thermoplastic substrate, although a tie layer can be used to improve adhesion to a glass substrate or to another coating or layer. For example, a tie coating or layer, also referred to as an adhesion layer or coating can be applied to the substrate and the barrier layer can be applied to the adhesion layer to improve adhesion of the barrier layer or coating to the substrate.

[0056] As described in U.S. Pat. Pub. No. 2014/0251859, another function of the tie coating or layer 102 has been discovered: a tie coating or layer 102 applied under a barrier coating or layer DOCKET NO. SIO-0087PC PATENT

104 can improve the function of a pH protective organo-siloxane coating or layer 106 applied over the barrier coating or layer 104.

[0057] The tie coating or layer 102 can be composed of, comprise, or consist essentially of

SiOxCy, in which x is between 0.5 and 2.4 and y is between 0.6 and 3. Alternatively, the atomic ratio can be expressed as the formula SiwOxCy. The atomic ratios of Si, O, and C in the tie coating or layer 102 are, as several options:

Si 100 : : O 50-150 : C 90-200 (i.e. w = l, x = 0.5 to 1.5, y = 0.9 to 2);

Si 100 : : O 70-130 : C 90-200 (i.e. w = l, x = 0.7 to 1.3, y = 0.9 to 2)

Si 100 : : O 80-120 : C 90-150 (i.e. w = l, x = 0.8 to 1.2, y = 0.9 to 1.5)

Si 100 : : O 90-120 : C 90- 140 (i.e. w = l, x = 0.9 to 1.2, y = 0.9 to 1.4), or

Si 100 : : O 92-107 : C 116-133 (i.e. w = = l, x = = 0.92 to 1.07, y = 1.16 to 1.33)

[0058] The atomic ratio can be determined by X-ray photoelectron spectroscopy (XPS).

Taking into account the H atoms, which are not measured by XPS, the tie coating or layer 102 may thus in one aspect have the formula SiwOxCyHz (or its equivalent SiOxCy), for example where w is 1, x is from about 0.5 to about 2.4, y is from about 0.6 to about 3, and z is from about 2 to about 9. Typically, a tie coating or layer 102 would hence contain 36% to 41% carbon normalized to 100% carbon plus oxygen plus silicon.

[0059] The barrier coating or layer for any embodiment defined in this specification (unless otherwise specified in a particular instance) is a coating or layer, optionally applied by PECVD as indicated in U.S. Pat. No. 7,985,188. The barrier coating preferably is characterized as a "SiOx" coating, and contains silicon, oxygen, and optionally other elements, in which x, the ratio of oxygen to silicon atoms, is from about 1.5 to about 2.9. The thickness of the SiOx or other barrier coating or layer can be measured, for example, by transmission electron microscopy (TEM), and its composition can be measured by XPS. The barrier layer is effective to prevent oxygen, carbon dioxide, or other gases from entering the container and/or to prevent leaching of the pharmaceutical material into or through the container wall. Not limited by the theory, dissolved oxygen by the polymer wall which released into the vessel later is one of the main oxidation pathways of the drug inside the vessel. The coating set of the current invention which is effective to minimize oxygen ingress preserves the contents inside the vessel against oxidation by oxygen gas, one of the main pathways of drug oxidation. DOCKET NO. SIO-0087PC PATENT

[0060] Referring again to Fig. 1A, the barrier coating or layer 104 of SiOx, in which x is between 1.5 and 2.9, is applied by PECVD directly or indirectly to the internal surface 16 of the sidewall 14 of the vial 10 (in this example, a tie coating or layer 102 is interposed between them) so that in a filled vial, the barrier coating or layer 104 is located between the internal surface 16 of the sidewall 14 and the contents (e.g., drug, active biologic or specimen) of the vial 10.

[0061 ] Preferred methods of applying the barrier layer and tie layer to the inner surface of the barrel 54 is by PECVD, such as described in, e.g., Applicant's U.S. Pat. App. Pub. No. 20130291632, which is incorporated by reference herein in its entirety.

[0062] Applicant has found that barrier layers or coatings of SiOx are eroded or dissolved by some fluids, for example aqueous compositions having a pH above about 5. Since coatings applied by chemical vapor deposition can be very thin - tens to hundreds of nanometers thick - even a relatively slow rate of erosion can remove or reduce the effectiveness of the barrier layer in less time than the desired shelf life of a product package. This is particularly a problem for fluid pharmaceutical and biologic compositions, since many of them have a pH of roughly 7, or more broadly in the range of 5 to 9, similar to (and including) the pH of blood and other human or animal fluids. The higher the pH of the pharmaceutical or biologic preparation, the more quickly it erodes or dissolves the SiOx coating. Optionally, this problem can be addressed by protecting the barrier coating or layer 104, or other pH sensitive material, with a pH protective organo-siloxane coating or layer 106.

[0063] Optionally, the pH protective organo-siloxane coating or layer 106 can be composed of, comprise, or consist essentially of SiwOxCyHz (or its equivalent SiOxCy) or SiwNxCyHz or its equivalent SiNxCy). The atomic ratio of Si : O : C or Si : N : C can be determined by XPS. Taking into account the H atoms, the pH protective coating or layer may thus in one aspect have the formula SiwOxCyHz, or its equivalent SiOxCy, for example where w is 1, x is from about 0.5 to about 2.4, y is from about 0.6 to about 3, and z is from about 2 to about 9.

[0064] Typically, expressed as the formula SiwOxCy, the atomic ratios of Si, O, and C are, as several options:

Si 100 : O 50-150 : C 90-200 (i.e. w = 1, x = 0.5 to 1.5, y = 0.9 to 2); Si 100 : O 70-130 : C 90-200 (i.e. w = 1, x = 0.7 to 1.3, y = 0.9 to 2) Si 100 : O 80-120 : C 90-150 (i.e. w = 1, x = 0.8 to 1.2, y = 0.9 to 1.5) DOCKET NO. SIO-0087PC PATENT

Si 100 : O 90-120 : C 90-140 (i.e. w = 1, x = 0.9 to 1.2, y = 0.9 to 1.4) Si 100 : O 92-107 : C 116-133 (i.e. w = 1, x = 0.92 to 1.07, y = 1.16 to 1.33) , or Si 100 : O 80-130 : C 90-150.

[0065] Alternatively, the organo-siloxane coating or layer can have atomic concentrations normalized to 100% carbon, oxygen, and silicon, as determined by XPS of less than 50% carbon and more than 25% silicon. Alternatively, the atomic concentrations are from 25 to 45% carbon, 25 to 65% silicon, and 10 to 35% oxygen. Alternatively, the atomic concentrations are from 30 to 40% carbon, 32 to 52% silicon, and 20 to 27% oxygen. Alternatively, the atomic concentrations are from 33 to 37% carbon, 37 to 47% silicon, and 22 to 26% oxygen.

[0066] Optionally, the atomic concentration of carbon in the pH protective coating or layer

106, normalized to 100% of carbon, oxygen, and silicon, as determined by XPS, can be greater than the atomic concentration of carbon in the atomic formula for the organosilicon precursor. For example, embodiments are contemplated in which the atomic concentration of carbon increases by from 1 to 80 atomic percent, alternatively from 10 to 70 atomic percent, alternatively from 20 to 60 atomic percent, alternatively from 30 to 50 atomic percent, alternatively from 35 to 45 atomic percent, alternatively from 37 to 41 atomic percent.

[0067] Optionally, the atomic ratio of carbon to oxygen in the pH protective coating or layer

106 can be increased in comparison to the organosilicon precursor, and/or the atomic ratio of oxygen to silicon can be decreased in comparison to the organosilicon precursor.

[0068] An exemplary empirical composition for a pH protective coating according to the present invention is S1O1.3 Co.s H3.6.

[0069] Optionally in any embodiment, the pH protective coating or layer 106 comprises, consists essentially of, or consists of PECVD applied silicon carbide.

[0070] Optionally in any embodiment, the pH protective coating or layer 106 is applied by employing a precursor comprising, consisting essentially of, or consisting of a silane. Optionally in any embodiment, the silane precursor comprises, consists essentially of, or consists of any one or more of an acyclic or cyclic silane, optionally comprising, consisting essentially of, or consisting of any one or more of silane, trimethylsilane, tetramethylsilane, Si2-Si4 silanes, triethyl silane, tetraethyl silane, tetrapropylsilane, tetrabutylsilane, or octamethylcyclotetrasilane, or tetramethylcyclotetrasilane . DOCKET NO. SIO-0087PC PATENT

[0071] Optionally in any embodiment, the pH protective coating or layer 106 comprises, consists essentially of, or consists of PECVD applied amorphous or diamond-like carbon. Optionally in any embodiment, the amorphous or diamond-like carbon is applied using a hydrocarbon precursor. Optionally in any embodiment, the hydrocarbon precursor comprises, consists essentially of, or consists of a linear, branched, or cyclic alkane, alkene, alkadiene, or alkyne that is saturated or unsaturated, for example acetylene, methane, ethane, ethylene, propane, propylene, n-butane, i- butane, butane, propyne, butyne, cyclopropane, cyclobutane, cyclohexane, cyclohexene, cyclopentadiene, or a combination of two or more of these. Optionally in any embodiment, the amorphous or diamond-like carbon coating has a hydrogen atomic percent of from 0.1% to 40%, alternatively from 0.5% to 10%, alternatively from 1% to 2%, alternatively from 1.1 to 1.8%.

[0072] Optionally in any embodiment, the pH protective coating or layer 106 comprises, consists essentially of, or consists of PECVD applied SiNb. Optionally in any embodiment, the PECVD applied SiNb is applied using a silane and a nitrogen-containing compound as precursors. Optionally in any embodiment, the silane is an acyclic or cyclic silane, optionally comprising, consisting essentially of, or consisting of silane, trimethylsilane, tetramethylsilane, Si2-Si4 silanes, triethylsilane, tetraethylsilane, tetrapropylsilane, tetrabutylsilane, octamethylcyclotetrasilane, or a combination of two or more of these. Optionally in any embodiment, the nitrogen-containing compound comprises, consists essentially of, or consists of any one or more of: nitrogen gas, nitrous oxide, ammonia or a silazane. Optionally in any embodiment, the silazane comprises, consists essentially of, or consists of a linear silazane, for example hexamethylene disilazane (HMDZ), a monocyclic silazane, a polycyclic silazane, a polysilsesquiazane, or a combination of two or more of these.

[0073] Optionally in any embodiment, the PECVD for the pH protective coating or layer 106 is carried out in the substantial absence or complete absence of an oxidizing gas. Optionally in any embodiment, the PECVD for the pH protective coating or layer 106 is carried out in the substantial absence or complete absence of a carrier gas.

[0074] Optionally an FTIR absorbance spectrum of the pH protective coating or layer 106

SiOxCyHz has a ratio greater than 0.75 between the maximum amplitude of the Si-O-Si symmetrical stretch peak normally located between about 1000 and 1040 cm-1, and the maximum amplitude of the Si-O-Si asymmetric stretch peak normally located between about 1060 and about 1100 cm-1. DOCKET NO. SIO-0087PC PATENT

Alternatively in any embodiment, this ratio can be at least 0.8, or at least 0.9, or at least 1.0, or at least 1.1, or at least 1.2. Alternatively in any embodiment, this ratio can be at most 1.7, or at most 1.6, or at most 1.5, or at most 1.4, or at most 1.3. Any minimum ratio stated here can be combined with any maximum ratio stated here, as an alternative embodiment.

[0075] Optionally, in any embodiment the pH protective coating or layer 106, in the absence of the medicament, has a non-oily appearance. This appearance has been observed in some instances to distinguish an effective pH protective coating or layer 106 from a lubricity layer (e.g., as described in U.S. Pat. No. 7,985,188), which in some instances has been observed to have an oily (i.e. shiny) appearance.

[0076] The pH protective coating or layer 106 optionally can be applied by PECVD of a precursor feed comprising an acyclic siloxane, a monocyclic siloxane, a polycyclic siloxane, a polysilsesquioxane, a monocyclic silazane, a polycyclic silazane, a polysilsesquiazane, a silatrane, a silquasilatrane, a silproatrane, an azasilatrane, an azasilquasiatrane, an azasilproatrane, or a combination of any two or more of these precursors. Some particular, non-limiting precursors contemplated for such use include octamethylcyclotetrasiloxane (OMCTS).

[0077] Optionally, an FTIR absorbance spectrum of the pH protective coating or layer 106 of composition SiOxCyHz has a ratio greater than 0.75 between the maximum amplitude of the Si-O-Si symmetrical stretch peak between about 1000 and 1040 cm-1, and the maximum amplitude of the Si- O-Si asymmetric stretch peak between about 1060 and about 1100 cm-1.

[0078] Other precursors and methods can be used to apply the pH protective coating or layer

106 or passivating treatment. For example, hexamethylene disilazane (HMDZ) can be used as the precursor. HMDZ has the advantage of containing no oxygen in its molecular structure. This passivation treatment is contemplated to be a surface treatment of the SiOx barrier layer with HMDZ. To slow down and/or eliminate the decomposition of the silicon dioxide coatings at silanol bonding sites, the coating must be passivated. It is contemplated that passivation of the surface with HMDZ (and optionally application of a few mono layers of the HMDZ-derived coating) will result in a toughening of the surface against dissolution, resulting in reduced decomposition. It is contemplated that HMDZ will react with the -OH sites that are present in the silicon dioxide coating, resulting in the evolution of NH3 and bonding of S-(CH3)3 to the silicon (it is contemplated that hydrogen atoms will be evolved and bond with nitrogen from the HMDZ to produce NH3). DOCKET NO. SIO-0087PC PATENT

[0079] Another way of applying the pH protective coating or layer 106 is to apply as the pH protective coating or layer 106 an amorphous carbon or fluorocarbon coating, or a combination of the two.

[0080] Amorphous carbon coatings can be formed by PECVD using a saturated hydrocarbon,

(e.g. methane or propane) or an unsaturated hydrocarbon (e.g. ethylene, acetylene) as a precursor for plasma polymerization. Fluorocarbon coatings can be derived from fluorocarbons (for example, hexafluoroethylene or tetrafluoroethylene). Either type of coating, or a combination of both, can be deposited by vacuum PECVD or atmospheric pressure PECVD. It is contemplated that that an amorphous carbon and/or fluorocarbon coating will provide better passivation of an SiOx barrier layer than a siloxane coating since an amorphous carbon and/or fluorocarbon coating will not contain silanol bonds.

[0081] It is further contemplated that fluorosilicon precursors can be used to provide a pH protective coating or layer 106 over a SiOx barrier layer. This can be carried out by using as a precursor a fluorinated silane precursor such as hexafluorosilane and a PECVD process. The resulting coating would also be expected to be a non-wetting coating.

[0082] Yet another coating modality contemplated for protecting or passivating a SiOx barrier layer is coating the barrier layer using a polyamidoamine epichlorohydrin resin. For example, the barrier coated part can be dip coated in a fluid polyamidoamine epichlorohydrin resin melt, solution or dispersion and cured by autoclaving or other heating at a temperature between 60 and 100°C. It is contemplated that a coating of polyamidoamine epichlorohydrin resin can be preferentially used in aqueous environments between pH 5-8, as such resins are known to provide high wet strength in paper in that pH range. Wet strength is the ability to maintain mechanical strength of paper subjected to complete water soaking for extended periods of time, so it is contemplated that a coating of polyamidoamine epichlorohydrin resin on a SiOx barrier layer will have similar resistance to dissolution in aqueous media. It is also contemplated that, because polyamidoamine epichlorohydrin resin imparts a lubricity improvement to paper, it will also provide lubricity in the form of a coating on a thermoplastic surface made of, for example, COC or COP.

[0083] Even another approach for protecting a SiOx layer is to apply as a pH protective coating or layer 106 a liquid- applied coating of a polyfluoroalkyl ether, followed by atmospheric plasma curing the pH protective coating or layer 106. For example, it is contemplated that the DOCKET NO. SIO-0087PC PATENT process practiced under the trademark TriboGlide® can be used to provide a pH protective coating or layer 106 that is also provides lubricity.

[0084] Thus, a pH protective coating for a thermoplastic syringe wall according to an aspect of the invention may comprise, consist essentially of, or consist of any one of the following: PECVD applied silicon carbide having the formula SiOxCyHz, in which x is from 0 to 0.5, alternatively from 0 to 0.49, alternatively from 0 to 0.25 as measured by XPS, y is from about 0.5 to about 1.5, alternatively from about 0.8 to about 1.2, alternatively about 1, as measured by XPS, and z is from 0 to 2 as measured by Rutherford Backscattering Spectrometry (RBS), alternatively by Hydrogen Forward Scattering Spectrometry (HFS); or PECVD applied amorphous or diamond-like carbon, CHz, in which z is from 0 to 0.7, alternatively from 0.005 to 0.1, alternatively from 0.01 to 0.02; or PECVD applied SiNb, in which b is from about 0.5 to about 2.1, alternatively from about 0.9 to about 1.6, alternatively from about 1.2 to about 1.4, as measured by XPS.

[0085] PECVD apparatus suitable for applying any of the PECVD coatings or layers described in this specification, including the tie coating or layer 102, the barrier coating or layer 104 or the organo-siloxane coating or layer 106, is shown and described in U.S. Pat. No. 7,985,188 and U.S. Pat. App. Pub. No. 20130291632. This apparatus optionally includes a vessel holder, an inner electrode, an outer electrode, and a power supply. A vessel seated on the vessel holder defines a plasma reaction chamber, optionally serving as its own vacuum chamber. Optionally, a source of vacuum, a reactant gas source, a gas feed or a combination of two or more of these can be supplied. Optionally, a gas drain, not necessarily including a source of vacuum, is provided to transfer gas to or from the interior of a vessel seated on the port to define a closed chamber.

[0086] One aspect of the current invention is that the coated plastic vessel is comparable to glass vessel in preserving the contents against sterilization induced degradation, blocking free radicals and/or oxygen. Another aspect of the current invention is that the coating set on the vessel surface provides an oxygen barrier blocking the oxygen from contacting the contents inside the vessel.

[0087] Another aspect of the current invention is a method for preventing or reducing migration of free radicals and/or byproducts thereof and/or oxygen ingress from a surface of a plastic substrate of a primary vessel into a product-containing space of the vessel. DOCKET NO. SIO-0087PC PATENT

[0088] The method comprising providing a radiation sterilized primary plastic vessel having a coating set deposited on an inner wall of the vessel, the coating set being effective to prevent or reduce migration of the free radicals and/or byproducts and/or oxygen from the surface of the substrate into the product containing space.

Exemplany PECVD Process for Trilayer Coating

[0089] The PECVD trilayer coating described in this specification can be applied, for example, as follows for a 1 to 5 mL vessel. Two specific examples are 1 mL thermoplastic resin syringe and a 5 mL thermoplastic resin drug vial. Larger or smaller vessels will call for adjustments in parameters that a person of ordinary skill can carry out in view of the teaching of this specification.

[0090] The apparatus used is the PECVD apparatus with rotating quadrupole magnets as described generally in this specification.

[0091] The general coating parameter ranges, with preferred ranges in parentheses, for a trilayer coating for a 1 mL syringe barrel are shown in the PECVD Trilayer Process General Parameters Tables (1 mL syringe and 5 mL vial).

DOCKET NO. SIO-0087PC PATENT

DOCKET NO. SIO-0087PC PATENT

[0092] In any embodiment of the invention, the pH protective coating or layer optionally can show an O-Parameter measured with attenuated total reflection (ATR) of less than 0.4, measured as:

O-Parameter = Intensity at 1253 cm-1 / Maximum intensity in the range from 1000 to 1100 cm-1.

[0093] In any embodiment of the invention, the pH protective coating or layer optionally can show an N-Parameter measured with attenuated total reflection (ATR) of less than 0.7, measured as:

N-Parameter = Intensity at 840 cm^"1/ Intensity at 799 cm- 1.

Alternative Trilayer Coating Process

[0094] The wall consists essentially of thermoplastic polymeric material defining a lumen. The wall has an interior surface facing the lumen and an exterior surface.

[0095] The tie coating or layer consists essentially of SiOxCy, wherein x is from about 0.5 to about 2.4 and y is from about 0.6 to about 3, each as determined by X-ray photoelectron spectroscopy (XPS), on the interior surface.

[0096] The barrier coating or layer consists essentially of SiOx, wherein x is from 1.5 to 2.9 as determined by XPS, between the tie coating or layer and the lumen.

[0097] The optional pH protective coating or layer consists essentially of SiOxCy, wherein x is from about 0.5 to about 2.4 and y is from about 0.6 to about 3, each as determined by XPS, between the barrier coating or layer and the lumen.

[0098] The coated vessel is formed by a process comprising several steps. A vessel is provided comprising the wall. A partial vacuum is drawn in the lumen. While maintaining the partial vacuum unbroken in the lumen, the tie coating or layer of SiOxCy is applied by a tie PECVD process comprising applying sufficient power (alternatively the same concept is referred to in this specification as "energy") to generate plasma within the lumen while feeding a gas comprising a linear siloxane precursor, optionally oxygen, and optionally an inert gas diluent.

[0099] Then, while maintaining the partial vacuum unbroken in the lumen, the plasma is extinguished. After that, while still maintaining the partial vacuum unbroken in the lumen, the barrier coating or layer is applied by a barrier PECVD process comprising applying sufficient power DOCKET NO. SIO-0087PC PATENT to generate plasma within the lumen while feeding a gas comprising a linear siloxane precursor and oxygen.

[00100] If the optional pH protective coating or layer is applied, this may optionally be done according to the following process.

[00101] Optionally after applying the barrier coating or layer, while maintaining the partial vacuum unbroken in the lumen, the plasma is extinguished.

[00102] Then optionally, while maintaining the partial vacuum unbroken in the lumen, the pH protective coating or layer of SiOxCy is applied by a pH protective PECVD process. The pH protective PECVD process comprises applying sufficient power to generate plasma within the lumen while feeding a gas comprising a linear siloxane precursor, optionally oxygen, and optionally an inert gas diluent.

Radiation Sterilization of Coated Vessels

[00103] In one aspect, the present invention is directed to vessels having plastic substrates

(including plastic primary containers) that are coated with one or more of the coatings described herein (or more broadly, the types of coatings described herein, i.e., tie coatings, barrier coatings and/or pH protective coatings) and that undergo radiation sterilization.

[00104] It should be understood that while the present invention is primarily described herein with respect to a vial 10, other embodiments of plastic primary containers are within the scope of the present invention, including but not limited to coated plastic syringes and coated plastic blood tubes. Moreover, other coated plastic vessels, as that term is broadly defined herein, are within the scope of the present invention. Thus, broadly, the present invention encompasses radiation sterilization of plastic substrates in any form, which are coated with the coating set as described herein.

[00105] In general, radiation comes in two forms: ionizing and non-ionizing. Radiation used in sterilization is ionizing radiation. For sterilization, ionizing radiation is a type of short wavelength, high intensity, radiation that is used to destroy microorganisms. Types of ionizing radiation used for sterilization include gamma irradiation, electron beam (e beam) irradiation and x-ray irradiation. The present invention may include any form of effective ionizing radiation for sterilization. DOCKET NO. SIO-0087PC PATENT

[00106] As discussed above, radiation sterilization of plastic vessels generates free radicals in the plastic, which (themselves or their byproducts, e.g., when they react with oxygen) may be harmful to products with which the vessels come in contact. However, Applicant contemplates that its proprietary coatings provide an effective barrier to these free radicals and related by-products, thus making radiation sterilization a feasible option for plastic vessels, particularly (albeit not exclusively) primary containers. In particular, Applicants contemplate that its coating technology, as described herein, would inhibit the deleterious effects of free radicals on biologicals, for example by preventing the migration of free radicals and/or byproducts thereof from within the plastic to the contents (e.g., drug)-packaging interface. Applicants further contemplate that its coatings do not themselves generate or proliferate free radicals and/or by-products thereof. This would enable manufacturers to safely sterilize plastic primary containers via e beam irradiation (or other types of irradiation), thus obviating the need for Tyvek® or other particle-generating material for sterilization.

[00107] It is contemplated that a radiation sterilized plastic primary container according to the present invention filled with an active biomolecule-containing product, would preserve the product against degradation from free radicals or byproducts thereof produced during radiation sterilization. Optionally, such preservation would protect the product against such degradation over the shelf-life of the product, which is optionally 6 months, optionally 12 months, optionally 18 months, optionally 24 months, optionally three years, optionally four years, optionally five years. Optionally, such preservation would protect the product against such degradation to a degree greater than or significantly greater than a reference container that is made not according to the present invention. The primary container according to the present invention would be coated with one or more of the coatings described in this specification.

Certain Embodiments

[00108] I. An irradiation sterilized plastic primary container comprising an active biomolecule-containing product therein, the container having an inner wall with one or more coatings (or coating set) deposited thereon, the outermost of the one or more coatings (or coating set) providing a contacting surface with the product, wherein the product held in the container is preserved against degradation from radiation-generated free radicals and/or their byproducts to a greater degree than a reference product held in an uncoated reference container that is otherwise DOCKET NO. SIO-0087PC PATENT structurally identical in all material respects to the plastic primary container, wherein the one or more coatings (or coating set) are selected from the group consisting of: a tie coating, a barrier coating, a pH protective coating, a trilayer coating set and any combination of the foregoing.

[00109] II. An irradiation sterilized plastic primary container comprising an active biomolecule-containing product therein, the container having an inner wall with one or more coatings (or coating set) deposited thereon, the outermost of the one or more coatings (or coating set) providing a contacting surface with the product, wherein the product held in the container is preserved against degradation from radiation-generated free radicals and/or their byproducts for the shelf-life of the product, wherein the shelf-life is optionally from six months to five years, optionally 6 months, optionally 12 months, optionally 18 months, optionally 24 months, optionally three years, optionally four years, optionally five years, wherein the one or more coatings (or coating set) are selected from the group consisting of: a tie coating, a barrier coating, a pH protective coating, a trilayer coating set and any combination of the foregoing.

[00110] ΙΠ. An irradiation sterilized vessel comprising a plastic substrate with a trilayer coating set deposited thereon.

[00111] IV. The vessel of Embodiment ΠΙ, wherein the surface of the substrate has free radicals and/or byproducts thereof located thereon which were created by radiation sterilization, wherein the trilayer coating set provides a barrier to the free radicals and/or byproducts, effectively preventing or reducing migration of the free radicals and/or byproducts from the surface of the substrate and/or within the plastic, across the trilayer coating set.

[00112] V. The vessel of Embodiment IV, wherein the vessel is a primary container having a product containing space, wherein the trilayer coating set effectively prevents or reduces migration of the free radicals and/or byproducts from the surface of the substrate and/or within the plastic into the product containing space.

[00113] VI. The vessel of Embodiment V, the vessel comprising contents prone to degradation by free radicals and/or byproducts thereof, wherein the trilayer coating set is effective in protecting the contents from degradation by radiation sterilization-generated free radicals and/or byproducts thereof.

[00114] VII. A method for preventing or reducing migration of free radicals and/or byproducts thereof from a surface of a plastic substrate of a primary container into a product-containing space of DOCKET NO. SIO-0087PC PATENT the container, the method comprising providing a radiation sterilized primary plastic container having one or more coatings (or coating set) deposited on an inner wall of the container, the one or more coatings (or coating set) being effective to prevent or reduce migration of the free radicals and/or byproducts from the surface of the substrate into the product containing space.

[00115 ] Vni. A method for preventing or reducing reaction of radiation sterilization-generated free radicals and/or byproducts thereof with contents of a primary container, the method comprising providing a radiation sterilized primary plastic container, wherein the container contains contents prone to degradation by free radicals and/or byproducts thereof, the container comprising one or more coatings (or coating set) deposited on an inner wall thereof, the one or more coatings (or coating set) being effective to protect the contents from degradation by radiation sterilization- generated free radicals and/or byproducts thereof located in the plastic of the vessel and/or on the inner wall.

[00116] IX. The method of Embodiment VIII, wherein the one or more coatings (or coating set) are selected from the group consisting of: a tie coating, a barrier coating, a pH protective coating, a trilayer coating set and any combination of the foregoing.

[00117] X. A method of sterilizing a vessel comprising providing a plastic vessel having one or more coatings (or coating set) deposited on a wall thereof and exposing the vessel to sufficient ionizing radiation to sterilize the vessel, wherein the method generates free radicals and/or byproducts thereof located in the plastic of the vessel and/or on the inner wall, there being no such free radicals and/or byproducts thereof or comparatively significantly less on an outermost surface of the one or more coatings (or coating set) than are present on the inner wall.

[00118] Various aspects of the invention will be illustrated in more detail with reference to the following Examples, but it should be understood that the present invention is not deemed to be limited thereto.

EXAMPLES

Example 1

Sterilization-Induced Free Radical Study Using ESR

[00119] A study is conducted testing the ability of Applicant' s proprietary coating technology

(as discussed in this specification) deposited on irradiated plastic primary containers, to block free DOCKET NO. SIO-0087PC PATENT radicals and/or byproducts thereof on the surface of the containers from contacting and damaging contents of the containers.

[00120] Electron spin resonance (ESR) is an analytical technique used to assess the presence of radicals. ESR utilizes electromagnetic fields to excite (flip) electron spins. Unpaired electrons give rise to ESR signal, so more radicals yield a higher signal. In this study, we analyze the difference between the polymer and PECVD coating surfaces, according to the following protocol.

[00121] Twenty-four 6 mL cyclic olefin copolymer (COP) vials are used in the study. Half of the vials are coated with an antistatic coating including inside the vials. The antistatic layer is a "sacrificial" PECVD-deposited coating comprising SiOH, which provides a means for desorbing subsequent layers. A 0.5-1 μηι pH protective layer is deposited by PECVD on the antistatic coated vials only. The pH protective layer coated vials are filled with water to strip the pH protective layer and then are dried completely in air. It is then verified whether there is enough coating powder remaining the coated vials to fill ESR quartz tubes. Where necessary, powder from two or more vials is combined.

[00122] Next, all twenty-four vials are stoppered and capped in a nitrogen purged glove box.

All vials are e beam sterilized, where the uncoated vials are the control population. A time lapse study of twelve weeks is conducted and it is found that the uncoated vials demonstrate higher ESR signals than coated vials. This indicates that the coating reduces the presence of radicals on the container surfaces. The time-lapse portion of the analysis shows the kinetics of radical reactivity in the vials.

Example 2

Teriparatide Oxidation In Vessels

[00123 ] A study is conducted testing the ability of Applicant' s proprietary coating technology

(as discussed in this specification) deposited on irradiated plastic primary containers, to block free radicals and/or byproducts thereof on the surface of the containers from contacting and damaging contents of the containers. Reports in the literature have shown that irradiated cyclic olefin copolymer (COC) containers produce free-radicals in the plastic that oxidize the drug product over prolonged exposure. Borosilicate glass containers have been reported to turn brown from irradiative sterilization. DOCKET NO. SIO-0087PC PATENT

[00124] A teriparatide drug formulation was filled into both glass, uncoated cyclic olefin polymer (COP), COP (6ml) vials coated with the Applicant's barrier system (i.e. tri-layer) coating technology (as discussed in this specification), sterilized by both gamma and e-beam, and then incubated for up to 10 weeks. The results, as shown in Fig. 2, show that the tri-layer coated vials show no significant sign of oxidative degradation and are comparable to glass. The uncoated COP containers show significant oxidation of teriparatide supporting the literature reports. Accordingly, the COP vials coated with the Applicant's coating technology support the use of either e-beam or gamma sterilization technologies for drug products.

Example 3

Teriparatide Oxidation VS Time

[00125] A study is conducted testing the ability of Applicant's proprietary coating technology

(as discussed in this specification) deposited on irradiated plastic primary containers, to block free radicals and/or byproducts thereof on the surface of the containers from contacting and damaging contents of the containers. Reports in the literature have shown that irradiated cyclic olefin copolymer (COC) containers produce free-radicals in the plastic that oxidize the drug product over prolonged exposure. Borosilicate glass containers have been reported to turn brown from irradiative sterilization.

[00126] Uncoated COP vials and trilayer coated COP vials (according to the coating method discussed in the specification) were used. 22 x 40 mm "5 mL" glass vials were purchased from a third party vendor, IVPacks LLC. Vials were sealed with silicone-treated bromo butyl stoppers and flip-off seals from West Pharmaceuticals. Gamma sterilization was carried out by Steris AST. Electron beam sterilization was carried out by Synergy Health. Teriparatide peptide was synthesized by Bachem Americas and assayed for purity by LC-MS.

[00127] 18.2 ΜΩ-cm ultrapure water was deoxygenated by nitrogen sparging. Each vial was filled with 5 mL and sealed with a manual crimp tool under a nitrogen atmosphere. Vials were stored in the dark at ambient conditions. At the indicated time points, three vials of each type were removed and dissolved oxygen levels inside the vial were measured using a needle-type microsensor inserted through the septum (Microx 4 with NTH-PSt7 microsensor; PreSens GmbH). Data is normalized to DOCKET NO. SIO-0087PC PATENT air-equilbrated water at the same conditions; error bars represent the standard deviation of measured oxygen levels.

[00128] Teriparatide was dissolved at 0.1 mg/mL in acetate buffer as for the commercial formulation (Forteo - Lilly) with 0.05% sodium acetate to prevent microbial growth. 0.5 mL was loaded into vials under ambient conditions and the vials were sealed by manual crimping, then stored in low light conditions. At the indicated time points, the contents of 3 vials were removed and pooled. 200 uL samples were analyzed by RP-HPLC (Shimadzu) using a Waters XBridge BEH C18 2.5 μηι, 4.5 x 50 mm column using a linear gradient from 25% to 40% mobile phase B over 20 minutes. Mobile phase A consisted of 0.1% TFA in water, mobile phase B consisted of 0.1% TFA in acetonitrile. Column temperature was 50 °C and the flow rate was 1.0 mL/min. Species abundance was quantified using peak area at 220 nm, and equivalent results were observed using 280 nm detection. Oxidation standards were prepared by incubating peptide samples with hydrogen peroxide (0.01% final v/v) for 30 minutes at room temperature. Three oxidized species were observed, as expected for oxidation of methionine 8 and/or 18 (Frelinger and Zull, J Biol Chem 259, 5507 (1984)). Total oxidation level was computed as ^(oxidized peak areas) / ^(oxidized + unoxidized peak areas).

[00129] Fig. 3 shows the results of the study. The results show that the coated vials show much less oxidative degradation than uncoated COP vials and that the coated vials are comparable to glass vials in this capacity. The results also show that electron beam and gamma sterilization have similar effects on the vials. Neither the glass nor the trilayer coated vials displayed a significant increase in oxidation due to sterilization. The results also demonstrate that the trilayer coating set is effective in protecting the contents from degradation by radiation sterilization-generated free radicals and/or byproducts thereof and/or oxygen. The results also demonstrate that the trilayer coated vials are comparable with glass vials in preserving the contents against oxidation caused by the free radicals induced by sterilization. Accordingly, the COP vials coated with the Applicant's coating technology support the use of either e-beam or gamma sterilization technologies for drug products.

Materials and Methods (for Examples 4 and 5)

Materials DOCKET NO. SIO-0087PC PATENT

[00130] All chemicals were ACS analytical grade or better. Chromatography solvents were

HPLC grade and 0.2 μιη sterile filtered. Ultrapure water was obtained using a Milli Q Reference system (Millipore, Milford, MA). 22 x 40 mm (6 mL) USP Type 1 borosilicate glass vials were purchased from International Vial Packaging (Lawrence, KS), along with 20 mm bromobutyl rubber stoppers and West flip off seals. Vials were made of cyclic olefin polymer (COP, Zeonex 690R) and then coated with trilayer coating if needed. Teriparatide (Human parathyroid hormone aa 1—34, > 95% pure by HPLC) was purchased from Toronto Research Chemicals (Toronto, Canada). Recombinant human erythropoietin was from Amega Biotech (Buenos Aires, Argentina). Glu-C protease, MS grade (specific activity > 500 U/mg) was purchased from Thermo Fisher Scientific.

Permeation Testing

[00131] Oxygen permeation through the vial wall materials was measured using non-contact fluorescence quenching (optode) sensors (MOCON, Minneapolis, MN). A sensor was affixed to the interior of a vial, which was then sealed under low oxygen conditions (< 0.2% oxygen) with a glass slide and epoxy. Containers were stored at 25 °C and the oxygen levels were monitored using a MOCON Optech-02 Platinum reader. The reader was calibrated at the start of the measurement using a calibration card supplied by the manufacturer that provides reference signals for air and "zero" oxygen. The same calibration setting was maintained for the duration of the measurement, and reader stability was periodically checked versus a sensor sealed inside a glass reference vial.

Sterilization

[00132] Vials were sterilized in cases of 96 using standard pharmaceutical procedures. Gamma sterilization was carried out by Steris AST (Spartanburg, SC) using a ⁶⁰Co source. The delivered dose was 31.1-36.7 kGy across the case. Electron beam sterilization was carried out by Steris AST (Denver, CO), with a delivered dose of 26.1-28.1 kGy.

Erythropoietin Oxidation Measurement

[00133] Erythropoietin oxidation was analyzed using a modified version of the glycopeptide mapping method described by Ohta et al (Ohta M, Kawasaki N, Hyuga S, Hyuga M, Hayakawa T (2001) Selective glycopeptide mapping of erythropoietin by on-line high-performance liquid chromatography electrospray ionization mass spectrometry. Chromatogr A 910(1): 1-11) and Nakamura et al (Nakamura K, et al. (2015) A strategy for the prevention of protein oxidation by drug product in polymer-based syringes. PDA J Pharm Sci Technol 69(1):88— 95). 200 μΐ_^ of protein DOCKET NO. SIO-0087PC PATENT solution was mixed with 300 μΐ_^ of 100 mM ammonium acetate solution (pH 8.0) and concentrated by diafiltration (Amicon Ultra 0.5, 10k MWCO, 14,000 x g, 20 minutes) to a volume of ~ 25 uL. 2 μg of Glu-C protease in 30 μΐ_^ ammonium acetate buffer (pH 8.0) was added and the mixture was incubated overnight at 37 °C. Digestion reactions were analyzed by RP-HPLC (Agilent 1200 series) using a Kinetex 2.6 μιη EVO C 18 2.1 x 50 mm column (Phenomenex, Torrance, CA) at a flow rate of 0.2 mL/min at 40 °C with the following gradient program (mobile phase A: 0.1% TFA in water, mobile phase B: acetonitrile): 0-5 min, isocratic 9% B; 5-23 min, 9-35% B; 23-28 min, isocratic 90% B, 28-35 min, isocratic 9% B. The injection volume was 50 μΐ_^ and absorbance was monitored at 220 and 280 nm. Species abundance was calculated using A₂₈₀, and oxidation fraction was computed from the areas of the oxidized and native peptide peaks.

[00134] Oxidation standards were prepared by incubating Erythropoietin samples with hydrogen peroxide (0.03% v/v from 30% stock) for 30 minutes at 37 °C. We estimate the uncertainty in quantification of oxidized fraction to be ~ 2% based on repeat LC analyses of samples from individual vials.

Example 4

Oxygen Permeation

[00135] This experiment was to evaluate the oxygen permeation for trilayer coated COP vessel versus that for uncoated COP vessel.

[00136] In order to isolate the oxygen permeation through the vial walls from oxygen ingress through the rubber stopper, vials were sealed with glass plates in an inert atmosphere, and oxygen levels were monitored for 15 days. Figure 4 shows the results of these tests: the oxygen partial pressure increased much faster in the uncoated COP vial than in the trilayer coated vial. If the permeability of the material remains constant vs. time, the oxygen partial pressure inside the vial should recover to ambient levels following first order kinetics:

with Pamb the ambient (external) partial pressure of oxygen and p(0) the partial pressure of oxygen inside the vial at t = 0. The characteristic permeation time Tp is related to the DOCKET NO. SIO-0087PC PATENT permeability coefficient P of the material (in moles 02 / atm / day) and the container volume V by the ideal gas law and Eq. 1:

(2)

where T is the temperature in Kelvin and R the ideal gas constant. The solid lines in Figure 4 show fits to Eq. 1 for the two materials, along with the fitted values for permeation versus time. The ratio of characteristic times

T P

~~ ψ ^~~ p is referred to as the barrier improvement factor (BIF) and reflects the relative rates of permeation: the PECVD coating slows oxygen ingress through the vial walls by a factor of 33 compared to the uncoated vials. Note that while Eq. 1 describes both sets of data well beyond t= 4 days, the earlier time points for the uncoated COP vials show a faster rise (leading to a larger fitted value for p(0)). We believe this is due to the oxygen initially dissolved in the COP vial walls prior to filling with nitrogen, and these data are consequently excluded from the fit. Corroborating this explanation, measurements in which COP containers were soaked in a nitrogen atmosphere for several days before measurement do not show this effect.

[00137] The results show that the trilayer coated vial reduces oxygen permeation by a factor of

33 compared to uncoated vial.

Example 5

Sterilization-induced oxidation: erythropoietin

[00138] Erythropoietin (EPO) is a highly glycosylated (~ 40% by mass) protein hormone ( 166 amino acids, molecular weight ~ 34 kDa depending on glycosylation state) that stimulates red blood cell production. Several versions of EPO (Epogen™, Aranesp™, EPREX™, etc) are used clinically to treat anemia arising from chronic kidney disease, cancer, and other causes. DOCKET NO. SIO-0087PC PATENT

[00139] Erythropoietin contains one internal methionine residue at position 54, and oxidation of this residue is associated with decreased bioactivity. Although detection of oxidation is challenging in the full-length protein, digestion into smaller fragments by the sequence-specific protease Glu-C allows detection of oxidation in the fragment containing Met-54 by RP-HPLC . Figure 5 A shows a clear shift in retention time for the peptide fragment containing Met-54 after treatment with hydrogen peroxide, while the other peaks are largely unchanged. As with teriparatide, we examined the effect of sterilization by storing EPO without stabilizers in vials under ambient conditions. Figure 5B shows results for the trilayer coated vials: after nearly six months of storage, no significant increase in oxidation level is seen for either the gamma-or electron beam- sterilized vials compared to the control. A similar level of oxidation (~ 6%) was observed in the glass and unsterilized COP vials, consistent with the results reported by Nakamura et al. (Koji Nakamura, et. al, A Strategy for the Prevention of Protein Oxidation by Drug Product in Polymer-Based Syringes, PDA J Pharm Sci and Tech 2015, 69, 88-95.) for COP syringes stored under similar conditions . Gamma- and electron-beam sterilized uncoated COP vials showed elevated levels of oxidation (~ 12% for both sterilization methods), though the values varied from vial to vial, perhaps reflecting differing radiation doses.

[00140] The results demonstrate that the sterilized trilayer coated vials are comparable to glass vials and unsterilized vials in preserving the contents against oxidation caused by sterilization- induced free radicals during a shelf life at least 6 months.

[00141] Taken together, the data in Examples 4 and 5 have shown the advantages of trilayer coated COP vessels on two phenomena associated with oxidation/degradation of the contents (e.g. drugs): oxygen permeation and sterilization-induced free radicals. In these experiments, the COP vessels with a trilayer PECVD coating, demonstrated significant advantages compared to uncoated COP vessels. The trilayer coating reduced oxygen permeation rate through the container walls by a factor of 33, and the two biologic peptides inside the vials did not show elevated levels of oxidation after storage in sterilized trilayer coated vials compared to unsterilized controls. Not limited to the theory, both effects are likely due to the same cause, namely the diffusion barrier provided by trilayer coating. Gas transport through materials is often described by a solubility-diffusion mechanism, in which the permeation rate depends both on the solubility of the gas in the material and how quickly molecules can move from one side to the other. DOCKET NO. SIO-0087PC PATENT

[00142] This study focused on electron beam and gamma irradiation sterilization methods, as ionizing radiation had been previously shown to cause oxidative damage to biomolecules stored in COP containers.

[00143] While the invention has been described in detail and with reference to specific examples thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

* * *

Claims

DOCKET NO. SIO-0087PC PATENT CLAIMS What is claimed is:

1. An irradiation sterilized plastic primary vessel comprising an active biomolecule- containing contents therein, the vessel having an inner wall with a coating set deposited thereon, the outermost of the coating set providing a contacting surface with the product, wherein the product held in the vessel is preserved against degradation to a greater degree than a reference product held in an uncoated reference vessel that is otherwise structurally identical in all material respects to the plastic primary vessel, wherein the coating set comprises:

• a surface layer or coating of any of, or combination of, the following:

• silicon-based barrier coating system;

• amorphous carbon coating;

• fluorocarbon coating;

• direct fluorination;

• antiscratch/antistatic coating;

• antistatic coating;

• antistatic additive compound in polymer;

• oxygen scavenging additive compound in polymer;

• colorant additive compound in polymer; DOCKET NO. SIO-0087PC PATENT

• or antioxidation additive compound in polymer;

• or combination of, and any combination of the foregoing.

2. The vessel of claim 1 , the degradation is caused by radiation-generated free radicals, and/or their byproducts, and/or oxygen gas.

3. The vessel of claim 2, the product comprises contents prone to degradation by free radicals and/or byproducts thereof and oxygen, wherein the coating set is effective in protecting the contents from degradation by radiation sterilization-generated free radicals and/or byproducts thereof and/or oxygen.

4. The vessel of claim 3,wherein the shelf-life of the product is optionally from six months to five years, optionally 6 months, optionally 12 months, optionally 18 months, optionally 24 months, optionally three years, optionally four years, optionally five years .

5. The vessel of claim 1, wherein the coating set is a trilayer coating.

6. The vessel of claim 1, wherein the trilayer coating effectively prevents or reduces migration of the free radicals and/or byproducts from the surface of the substrate and/or within the plastic into the product containing space.

7. The vessel of claim 1 , wherein the plastic comprises an olefin polymer; polypropylene (PP); polyethylene (PE); cyclic olefin copolymer (COC); cyclic olefin polymer (COP); polymethylpentene; polyester; polyethylene terephthalate; polyethylene naphthalate; polybutylene terephthalate (PBT); PVdC (polyvinylidene chloride); polyvinyl chloride (PVC); polycarbonate; polymethylmethacrylate; polylactic acid; polylactic acid; polystyrene; hydrogenated polystyrene; poly(cyclohexylethylene) (PCHE); epoxy resin; nylon; polyurethane polyacrylonitrile; polyacrylonitrile (PAN); an ionomeric resin; Surlyn® ionomeric resin; optionally a cyclic olefin polymer (COP), cyclic olefin copolymer (COC) or polycarbonate; optionally a COP; optionally a COC.

8. The vessel of claim 1, wherein the surface of the substrate has free radicals and/or byproducts thereof located thereon which were created by radiation sterilization, wherein the coating set provides a barrier to the free radicals and/or byproducts, effectively preventing or reducing migration of the free radicals and/or byproducts from the surface of the substrate and/or within the plastic, across the trilayer coating set into contact with the contents in the vessel. DOCKET NO. SIO-0087PC PATENT

9. The vessel of claim 1 , wherein the coating set provides an oxygen barrier blocking the oxygen from contacting the contents inside the vessel.

10. The vessel of claim 1, wherein the vessel is comparable to glass vessel in preserving the contents against sterilization induced degradation, blocking free radicals and/or oxygen.

11. A method for preventing or reducing migration of free radicals and/or byproducts thereof and/or oxygen ingress from a surface of a plastic substrate of a primary vessel into a product- containing space of the vessel, the method comprising providing a radiation sterilized primary plastic vessel having a coating set deposited on an inner wall of the vessel, the coating set being effective to prevent or reduce migration of the free radicals and/or byproducts and/or oxygen from the surface of the substrate into the product containing space.

12. The method of claim 11, wherein the method preventing or reducing reaction of radiation sterilization-generated free radicals and/or byproducts thereof and/or oxygen with contents of the primary vessel, the method comprising providing a radiation sterilized primary plastic container, wherein the vessel contains contents prone to degradation by free radicals and/or byproducts thereof and/or oxygen, the vessel comprising a coating set deposited on an inner wall thereof, the coating set being effective to protect the contents from degradation by radiation sterilization-generated free radicals and/or byproducts thereof and/or oxygen located in the plastic of the vessel and/or on the inner wall.

13. The method of claim 11 , wherein the coating set is selected from the group consisting of: a tie coating, a barrier coating, a pH protective coating, a trilayer coating set, a surface coating and any combination of the foregoing.

14. The method of claim 11, wherein the plastic substrate comprises an olefin polymer; polypropylene (PP); polyethylene (PE); cyclic olefin copolymer (COC); cyclic olefin polymer (COP); polymethylpentene; polyester; polyethylene terephthalate; polyethylene naphthalate; polybutylene terephthalate (PBT); PVdC (polyvinylidene chloride); polyvinyl chloride (PVC); polycarbonate; polymethylmethacrylate; polylactic acid; polylactic acid; polystyrene; hydrogenated polystyrene; poly(cyclohexylethylene) (PCHE); epoxy resin; nylon; polyurethane polyacrylonitrile; polyacrylonitrile (PAN); an ionomeric resin; Surlyn® ionomeric resin; optionally a cyclic olefin polymer (COP), cyclic olefin copolymer (COC) or polycarbonate; optionally a COP; optionally a COC. DOCKET NO. SIO-0087PC PATENT

15. A method of sterilizing a vessel comprising providing a plastic vessel having a coating set deposited on a wall thereof and exposing the vessel to sufficient ionizing radiation to sterilize the vessel, wherein the method generates free radicals and/or byproducts thereof located in the plastic of the vessel and/or on the inner wall, there being no such free radicals and/or byproducts thereof or comparatively significantly less on an outermost surface of the coating set than are present on the inner wall.