Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/48—Preparations in capsules, e.g. of gelatin, of chocolate
  • A61K9/50—Microcapsules having a gas, liquid or semi-solid filling; Solid microparticles or pellets surrounded by a distinct coating layer, e.g. coated microspheres, coated drug crystals
  • A61K9/51—Nanocapsules; Nanoparticles
  • A61K9/5107—Excipients; Inactive ingredients
  • A61K9/513—Organic macromolecular compounds; Dendrimers
  • A61K9/5146—Organic macromolecular compounds; Dendrimers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyethylene glycol, polyamines, polyanhydrides
  • A61K9/5153—Polyesters, e.g. poly(lactide-co-glycolide)
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K33/00—Medicinal preparations containing inorganic active ingredients
  • A61K33/20—Elemental chlorine; Inorganic compounds releasing chlorine
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K41/00—Medicinal preparations obtained by treating materials with wave energy or particle radiation ; Therapies using these preparations
  • A61K41/0057—Photodynamic therapy with a photosensitizer, i.e. agent able to produce reactive oxygen species upon exposure to light or radiation, e.g. UV or visible light; photocleavage of nucleic acids with an agent
  • A61K41/0071—PDT with porphyrins having exactly 20 ring atoms, i.e. based on the non-expanded tetrapyrrolic ring system, e.g. bacteriochlorin, chlorin-e6, or phthalocyanines
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/06—Organic compounds, e.g. natural or synthetic hydrocarbons, polyolefins, mineral oil, petrolatum or ozokerite
  • A61K47/08—Organic compounds, e.g. natural or synthetic hydrocarbons, polyolefins, mineral oil, petrolatum or ozokerite containing oxygen, e.g. ethers, acetals, ketones, quinones, aldehydes, peroxides
  • A61K47/10—Alcohols; Phenols; Salts thereof, e.g. glycerol; Polyethylene glycols [PEG]; Poloxamers; PEG/POE alkyl ethers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/06—Organic compounds, e.g. natural or synthetic hydrocarbons, polyolefins, mineral oil, petrolatum or ozokerite
  • A61K47/26—Carbohydrates, e.g. sugar alcohols, amino sugars, nucleic acids, mono-, di- or oligo-saccharides; Derivatives thereof, e.g. polysorbates, sorbitan fatty acid esters or glycyrrhizin
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/30—Macromolecular organic or inorganic compounds, e.g. inorganic polyphosphates
  • A61K47/32—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. carbomers, poly(meth)acrylates, or polyvinyl pyrrolidone
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/30—Macromolecular organic or inorganic compounds, e.g. inorganic polyphosphates
  • A61K47/34—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. polyesters, polyamino acids, polysiloxanes, polyphosphazines, copolymers of polyalkylene glycol or poloxamers
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
  • A61K47/30—Macromolecular organic or inorganic compounds, e.g. inorganic polyphosphates
  • A61K47/42—Proteins; Polypeptides; Degradation products thereof; Derivatives thereof, e.g. albumin, gelatin or zein
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K9/00—Medicinal preparations characterised by special physical form
  • A61K9/14—Particulate form, e.g. powders, Processes for size reducing of pure drugs or the resulting products, Pure drug nanoparticles
  • A61K9/19—Particulate form, e.g. powders, Processes for size reducing of pure drugs or the resulting products, Pure drug nanoparticles lyophilised, i.e. freeze-dried, solutions or dispersions
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P13/00—Drugs for disorders of the urinary system
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P17/00—Drugs for dermatological disorders
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P19/00—Drugs for skeletal disorders
  • A61P19/02—Drugs for skeletal disorders for joint disorders, e.g. arthritis, arthrosis
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P19/00—Drugs for skeletal disorders
  • A61P19/04—Drugs for skeletal disorders for non-specific disorders of the connective tissue
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P27/00—Drugs for disorders of the senses
  • A61P27/02—Ophthalmic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P29/00—Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents

Definitions

• GLYCOLIC ACID (PLGA) FOR PHOTODYNAMIC THERAPY (PDT)
• the present invention concerns the preparation of nanoparticle formulations containing hydrophobic photosensitizers and their use in photodynamic therapy, particularly for photodynamic tumor therapy, using intravenous administration.
• Photodynamic therapy is one of the most promising new techniques now being explored tor use in a variety of medical applications and particularly is a well-recognized treatment for the destruction of tumors.
• Photodynamic therapy uses light and a photosensitizer (a dye) to achieve its desired medical effect.
• a large number of naturally occurring and synthetic dyes have been evaluated as potential photosensitizers for photodynamic therapy.
• Perhaps the most widely studied class of photosensitizers is the tetrapyrrolic macrocyclic compounds. Among them, especially porphyrins and ch!orins have been tested for their PDT efficacy.
• Porphyrins are macrocyclic compounds with bridges of one carbon atom joining pyrroles to form a characteristic tetrapyrrole ring structure.
• porphyrin derivatives including chlorins containing one di hydro-pyrrole unit and bacteriochlorins containing two dihydro-pyrrole units. Both mentioned porphyrin derivatives possessing potential for PDT can either be derived from natural sources or from total synthesis.
• chlorins have the advantage that they possess a more favorable absorption spectrum, i.e. they have a more intense absorption in the red and near- infrared region of the electromagnetic spectrum. As light of longer wavelength penetrates deeper into the tissue it is thus possible to treat e.g. more expanded tumors, when PDT is employed for tumor therapy.
• Nanoparticles are intensively investigated as carriers for lipophilic drug substances.
• a nanoparticle formulation of the anti-cancer drug Paclitaxel based on human serum albumin (HSA) has been approved recently by regulatory authorities in Europe and the USA.
• Nanoparticles in general are solid colloidal particles, typically, ranging in size from lOnm to lOOOnm. They consist of macromolecular materials in which the active ingredient is dissolved, entrapped or encapsulated, and/or to which the active principle is absorbed or attached. Many different sorts of nanoparticle material have been investigated, i.e. quantum dots, silica-based nanoparticles, photonic crystals, liposomes, nanoparticles based on different polymers of natural and synthetic origin, and metal-based nanoparticles. Nanoparticles in combination with photosensitizers have been investigated i.e.
• imaging approaches such as the nanoparticles, disclosed in Patent Publication N° US 2007/0148074A 1 by Sadoqi et al., comprising biodegradable polymer materials entrapping near-infrared dyes for using them in bio-imaging.
• imaging approaches such as the nanoparticles, disclosed in Patent Publication N° US 2007/0148074A 1 by Sadoqi et al., comprising biodegradable polymer materials entrapping near-infrared dyes for using them in bio-imaging.
• other nanoparticle systems combining fluorescence imaging and magnetic resonance imaging, especially in combination with metal (iron) based nanoparticles are known in the art (see Mulder et. al, Ncmomed., 2007, 2, 307-324; Kim et.al, Nanoteclmoi, 2002, 13, 610-614; Primo et at, J. Magnetism Magn. Mater., 2007, 311, 354-357) but such developments are unrelated to the present invention.
• carrier systems for photosensitizers are nanoparticles that consist of biocompatible materials. Such carrier systems could significantly improve the treatment regimen of photodynamic therapy.
• a carrier system with such known high biocompatibility is e.g. poly(DL-lactic-co-glycolic acid) (PLGA).
• PLGA material has successfully been formulated as nanoparticles.
• PLGA-based nanoparticles as carriers for photosensitizers known in the art (see Gomes et al., Photomed. Laser Surg., 2007, 25, 428- 435; Ricci-Junior et al., J. Microencapsul, 2006, 23, 523-538; Ricci-Junior et al., Int. J. Pharm., 2006, 310, 187-195; Saxena et al., Int. J. Pharm., 2006, 308, 200-204; McCarthy et al., Abstracts of Papers, 229 th ACS Meeting, 2005; Vargas et al., Int. J.
• the PLGA-based nanoparticles used as carriers for photosensitizers are intended for a rapid release of the drug, preferably within about 60 seconds, after the nanoparticles are introduced into an environment containing serum proteins and, therefore, are not well suited for a drug transport to the target cells and tissues.
• high concentrations of polyvinyl alcohol (PVA) stabilizer in the range of about 5-20% in the aqueous phase are employed.
• nanoparticle formulations for parenteral administration require that the sterility of the formulation according to pharmacopoeia] specifications can be assured.
• the problem of sterility of nanoparticle photosensitizer formulations involving PLGA is challenging because of the lability of the nanoparticle matrix material as well as the lability of the photosensitizer.
• Conventional methods of sterilization (autoclaving, use of ethylene oxide, gamma-irradiation) are incompatible with these photosensitizer formulations (see Athanasiou et. al, Biomaterials, 1996, 17, 93-102; Volland et. al, J. Contr. Rel., 1994, 31, 293-305).
• sterile filtration through membrane filters of a defined size for such chemically and thermally sensitive materials.
• Pore size for sterile filtration is usually 0.22 ⁇ m whereas nanoparticles of the present invention are in the size range between 100 and 500nm. Therefore, sterile filtration has its drawbacks and is not generally compatible with the nanoparticles that are subject of the present invention.
• the formulation can be freeze dried and later be reconstituted in an aqueous medium.
• photosensitizers of the present invention which are of the chlorin or bacteriochlorin type (i.e. tetrapyrro!es carrying one or two dihydro-pyrrole units)
• photosensitizers of the present invention which are of the chlorin or bacteriochlorin type (i.e. tetrapyrro!es carrying one or two dihydro-pyrrole units)
• photosensitizers of the present invention which are of the chlorin or bacteriochlorin type (i.e. tetrapyrro!es carrying one or two dihydro-pyrrole units)
• such systems are especially sensitive to oxidation and photo-chemical modifications induced by the handling conditions that are often used for nanoparticle preparation (see Hongying et al., Dyes Pigm, 1999, 43, 109-1 17; Hadjur et al., J. Phoiochem. Photo
• Nanoparticle Aptamer Conjugates comprising a phorodsitizer that forms the central core of the nanoparticle, a biodegradable polymer shell and a targeting aptamer (e.g. ErbB3 receptor-specific aptamer) but does not address the problem of sterility of the nanoparticle photosensitizer formulations nor the freeze-drying process required to obtain a stable nanoparticle photosensitizer formulation.
• a targeting aptamer e.g. ErbB3 receptor-specific aptamer
• present invention provides PLGA-based nanoparticle formulations and methods of preparation for photosensitizers suitable for parenteral application that can be prepared for such sensitive compounds as chlorins and bacteriochlorins.
• nanoparticle formulations for hydrophobic photosensitizers used for photodynamic therapy based on biocompatible PLGA material it is an objective of the present invention to provide nanoparticle formulations for hydrophobic photosensitizers used for photodynamic therapy based on biocompatible PLGA material.
• PLGA poly(DL-lactic-co-gIycolic acid)
• a stabilizing agent preferably selected from the group consisting of polyvinyl alcohol), polysorbate, poloxamer, and human serum albumin and the like.
• nanoparticle formulations for hydrophobic photosensitizers which enable an effective drug transport to target cells and tissues combined with a drug release after cellular accumulation
• the nanoparticles of the present invention are stable enough to allow freeze drying and reconstitution in an aqueous medium.
• present invention provides compositions, which are stable in storage, and a method of production of pharmaceutical based nanoparticulate formulations for clinical use in photodynamic therapy comprising a hydrophobic photosensitizer, poly(lactic-co- glycolic) acid and stabilizing agents.
• These nanoparticulate formulations provide therapeutically effective amounts of photosensitizer for parenteral administration.
• tetrapyrro!e derivatives can be used as photosensitizers whose efficacy and safety are enhanced by such nanoparticulate formulations. It also teaches the method of preparing PLGA-based nanoparticles under sterile conditions.
• PLGA-based nanoparticles have a mean particle size less than 500nm and the photosensitizer is temoporfin, 5, 10, l 5,20-tetrakis(3-hydroxyphenyl)-chlorin (mTHPC).
• the photosensitizer 2,3-dihydroxy-5, 10, 15, 20-tetrakis(3- hydroxyphenyl)-chIorin (mTHPD-OH) is formulated as a nanoparticle for parenteral administration.
• preferred photosensitizer is 5, l0, 15,20-tetrakis(3- hydroxyphenyl)-porphyrin (mTHPP).
• the formulations can be used for treating hyperplasic and neoplasic conditions, inflammatory problems, and more specifically to target tumor cells.
• Fig. 1 depicts the preferred structures of chlorins and bacteriochlorins to be used in present invention.
• Fig. 2 depicts the structure of the specifically preferred chlorins to be formulated in nanoparticles according to the present invention.
• Fig. 3 shows a curve which indicates that depending upon the ratio of drug to PLGA a drug loading efficiency between 2 and 320 ⁇ g mTHPP per milligram PLGA could be achieved.
• Fig. 4A and B shows confocal laser scanning microscopy images of cellular uptake and intracellular distribution of PLGA based nanoparticles with the photosensitizer 5, 10, 15,20-tetrakis(3-hydroxyphenyl)-porphyrin (mTH PP).
• Fig. 5A and B shows confocal laser scanning microscopy images of cellular uptake and intracellular distribution of PLGA based nanoparticles with the photosensitizer 5, 10,15,20-tetrakis(3-hydroxyphenyl)-chlorin (mTHPC).
• Fig. 6 shows the results of phototoxicity of 3 ⁇ mTHPC, and different mTHPC loaded PLGA nanoparticles on Jurkat cells after different incubation times.
• Fig. 7 shows the results of intracellular uptake of 3 ⁇ mTHPC, and different n/THPC loaded PLGA nanoparticles by Jurkat cells after different incubation times.
• the methods of preparation of the described nanoparticle systems of the present invention provide systems that enable a drug release over several hours even in the presence of serum proteins and, therefore, are suitable for a drug transport to target cells and tissues. This is in contrast with the immediate decomposition of particles and release of photosensitizers in the prior art use of PLGA nanoparticle systems. Moreover, a high variability of drug release kinetics is obtained depending on the way the excipients are used during particle preparation.
• nanoparticle formulations of photosensitizers are vital to the development of nanoparticle formulations of photosensitizers. It has now been found that such PLGA-based nanoparticle photosensitizer formulations suitable for clinical applications can be prepared by an aseptic manufacturing process.
• present invention provides methods for the production of sterile PLGA-based photosensitizer-loaded nanoparticles of a mean particle size less than 500nm, with the photosensitizers being chlorins or bacteriochlorins.
• nanoparticle pharmaceutical formulations of the present invention are stable enough to allow freeze drying and reconstitution in an aqueous medium. Therefore present invention addresses the problem of suitable nanoparticle pharmaceutical formulations of hydrophobic photosensilizers for photodynamic therapy that meet the necessities for a parenteral administration in clinical practice.
• nanoparticle photosensitizer formulations based on PLGA in PDT include, but are not limited to dermatological disorders, ophthalmological disorders, urological disorders, arthritis and similar inflammatory diseases. More preferably, therapeutic uses of nanoparticle photosensitizer formulations based on PLGA in PDT comprise the treatment of tumor tissues, neoplasia, hyperplasia and related conditions.
• the described nanoparticle systems of PLGA-based nanoparticle formulations for chlorins and bacteriochlorins for parenteral application can be prepared in the presence of reduced amounts of stabilizers (i.e. 1.0% PVA).
• stabilizers i.e. 1.0% PVA.
• the systems enable a drug release over several hours even in the presence of serum proteins and, therefore, are suitable for transporting a drug to target cells and tissues.
• the prolonged drug release enables the attachment of drug targeting ligands to the particle surface (such as antibodies) for a more advanced transport of photosensitizer to target cells and tissues.
• the photosensitizer is attached by incorporation in the particle matrix, 2) is attached by adsorption to the particle matrix, 3) or is attached by incorporation in and adsorption to the particle matrix, resulting in a high variability of drug release kinetics.
• the PLGA-based nanoparticles have a mean particle size less than 500nm and the photosensitizer is temoporfin, 5, 10, 15,20-tetrakis(3-hydroxyphenyl)-chlorin (mTHPC).
• the PLGA-based nanoparticles have a mean particle size less than 500nm and the photosensitizer is 2,3-dihydroxy-5, 10, 15,20- tetrakis(3-hydroxyphenyl)-chlorin (mTHPD-OH).
• the PLGA-based nanoparticles have a mean particle size less than 500nm and the photosensitizer is 5, 10, 15,20-tetrakis(3-hydroxyphenyl)-porphyrin
• the invention provides methods to prepare formulations of photosensitizer-containing nanoparticles preferably using photosensitizers of the chlorin and bacteriochlorin type.
• the nanoparticles prepared by the methods disclosed below have a predictable size and uniformity (in size distribution).
• the nanoparticles are prepared in an aseptic manufacturing process.
• Preferred PLGA-based nanoparticles have a mean size less than 500nm.
• the term "diameter” is not intended to mean that the nanoparticles have necessarily a spherical shape. The term refers to the approximate average width of the nanoparticles.
• the PLGA-based nanoparticles can be prepared so that the photosensitizer loading can be varied in a wide concentration range (2 to 320 ⁇ g photosensitizer per mg nanoparticles).
• the PLGA-based nanoparticles can be prepared so that the photosensitizer is attached by incorporation in the particle matrix, is attached by adsorption to the particle matrix or is attached by incorporation in and adsorption to the particle matrix, resulting in a high variability of drug release kinetics.
• Drug targeting effectiveness of present nanoparticle systems may be enhanced with one or more ligands bound to PLGA-nanoparticles, maintaining the photosensitizer chemical entity by not bonding to photosensitizer molecules.
• the nanoparticles of the invention may be dehydrated for improved stability on storage.
• the preferred method of dehydration is freeze-drying or lyophilisation.
• a lyoprotectant may be used as an additive to improve the stability during the freeze-drying and during reconstitution in an aqueous medium.
• the present invention provides methods for the use of nanoparticle photosensitizer formulations based on PLGA in PDT, comprising the administration of the nanoparticles, their accumulation in the target tissue and the activation of the photosensitizer by light of a specific wavelength.
• the administration is preferably by parenteral means such as, but not limited to, intravenous injection.
• polymer to be used in the present invention is poly(D,L- lactide-co-glycolide) PLGA, preferably characterised by a copolymer ratio of 50:50 or 75:25.
• PLGA to be used for the preparations underlying the present invention was obtained from Boehringer Ingelheim (Resomer RG502H and Resomer RG504H).
• the photosensitizers to be used in the present invention are preferably but not limited to tetrapyrroles of the chlorin and bacteriochlorin type.
• Such photosensitizers can either be derived from natural sources or by total synthesis.
• the total synthesis of chlorins and bacteriochlorins can be performed by first synthesizing the porphyrin and then transferring it to a chlorine or bacteriochlorin system (e.g. R. Bonnett, R. D. White, U.-J. Winfield, M. C. Berenbaum, Hydroporphyrins of the m yo-tetra(hydroxyphenyl)porphyrin series as tumor photosensitizers, Biochem. J. 1989, 261, 277-280).
• a chlorine or bacteriochlorin system e.g. R. Bonnett, R. D. White, U.-J. Winfield, M. C. Berenbaum, Hydroporphyrins of the
• chlorins and bacteriochlorins to be used with the present invention have the following preferred structure depicted in Fig. I .
• Specifically preferred chlorins to be formulated in nanoparticles according to the present invention have the structure depicted in Fig. 2.
• the PLGA-based nanoparticles of the present invention were prepared by an emulsion-diffusion-evaporation process using an Ultra-Turrax dispersion unit. An adsorptive binding of the photosensitizer to the particle matrix, an incorporative binding into the particle matrix and a combination of adsorptive and incorporative binding to the particle matrix can be achieved. Drug loaded nanoparticles can be freeze dried in the presence of cryoprotective agents such as glucose, trehalose, sucrose, sorbitol, mannitol and the like.
• cryoprotective agents such as glucose, trehalose, sucrose, sorbitol, mannitol and the like.
• the present invention is further illustrated by the following examples, but is not limited thereby.
• the PLGA-based nanoparticles of the present invention were prepared by an emulsion-diffusion-evaporation process using an Ultra-Turrax dispersion unit (Ultra Turrax T25 digital, I A, Staufen, Germany).
• This organic solution was added to 10mL of a 1% polyvinyl alcohol (PVA) stabilized aqueous solution.
• PVA polyvinyl alcohol
• Uitra-Turrax dispersion unit 17,000rpm, 5min
• an oil-in-water nanoemulsion was formed.
• the emulsion was added to 40mL of an aqueous PVA stabilized solution to induce the formation of nanoparticles after complete diffusion of the organic solvents into the aqueous external phase.
• Permanent mechanical stirring (550rpm) was maintained for 18h to allow the complete evaporation of ethyl acetate.
• the particles were purified by 5 cycles of centrifugation ( 16, 100G; 8min) and redispersion in 1.0mL water in an ultrasonic bath (5min). All of the aqueous solutions used for particle preparation were sterile and pre-filtered through a membrane with a pore size of 0.22 ⁇ (Schleicher und Schiill, Dassel, Germany). All of the equipment used was autoclaved at 121 °C over 20min. All handling steps for particle preparation were performed under a laminar airflow cabinet.
• Average particle size and polydispersity were measured by photon correlation spectroscopy using Zetasizer 3000 HSA (Malvern Instruments, Malvern, UK). Nanoparticle content was determined by microgravimetry.
• Direct quantification procedure The PLGA-nanoparticles were dissolved in acetone and the solution was measured photometrically at 5 l 2nm for mTHPP to determine the content of photosensitizer. Depending upon the ratio of drug to PLGA a drug loading efficiency between 2 and 320 ⁇ g mTHPP per milligram PLGA could be achieved (Fig. 3).
• PRT Pressure Rise Test
• Nanoparticies were prepared according to example l a with the exception that mTHPC was used instead of mTHPP. mTHPC was photometrically quantified at 517nm. Depending upon the ratio of drug to PLGA a drug loading efficiency between 2 and 320 ⁇ g mTHPC per milligram PLGA could be achieved.
• mTHPC loaded nanoparticies were characterized as described within example la.
• example l a The above described standard method (example l a) was used to prepare empty PLGA-nanoparticIes. The preparation steps were performed as described for example la except for the addition of the photosensitizer mTHPP.
• a PVA-stabilized mTHPP solution was prepared. Therefore, 25mg mTHPP was solved in 5mL ethyl 1cetate and afterwards lOmL of a 1 % aqueous PVA solution was added. With an Ultra-Turrax dispersion unit an emulsion was prepared. The emulsion was added to 40mL PVA solution ( 1%). Permanent mechanical stirring (550rpm) was maintained for 18h to allow the complete evaporation of ethyl acetate.
• a volume of the PLGA-nanoparticle suspension corresponding to 10mg nanoparticles was centrifuged ( 16, 100G: 8min) and the supernatant was discarded.
• the nanoparticles were redispersed in the PVA-stabilized mTHPP solution using an ultrasonic bath (5min).
• the mixture was agitated (Thermomixer comfort, Eppendorf, Hamburg, Germany) for 18h (500rpm, 20°C) to achieve adsorption equilibrium of mTHPP to the particle surface.
• the nanoparticles were purified as previously described.
• a drug loading efficiency between 2 and 80 ⁇ g mTHPP (according to the standard protocol typically 20 ⁇ g) per milligram PLGA could be achieved.
• mTHPP loaded (adsorbed) nanoparticles were characterized and lyophilized as described within example 1 a.
• Nanoparticles were prepared according to example I c with the exception that mTHPC was used instead of mTHPP. mTHPC was photometrically quantified at 5 ! 7nm.
• a drug loading efficiency between 2 and 80 ⁇ g mTHPC (according to the standard protocol typically 20 ⁇ g) per milligram PLGA could be achieved.
• PLGA nanoparticles were prepared according to example la.
• the resulting nanoparticles were washed with aqueous 5% (m/V) PVA solution instead of purified water in order to displace the adsorptive bound mTHPP from the nanoparticle surface. After 3 cycles of washing with PVA solution the nanoparticles were further purified by repeated centrifugation and redispersion in purified water.
• 80 ⁇ g mTHPP (according to the standard protocol typically 50 g) per milligram PLGA could be achieved.
• mTHPP loaded (incorporated) nanoparticles were characterized and lyophi!ized as described within example 1 a.
• Nanoparticles were prepared according to example le with the exception that mTHPC was used instead of mTHPP. mTHPC was photometrically quantified at 517nm.
• a drug loading efficiency between 15 and 80 ⁇ g mTHPC (according to the standard protocol typically 50 ⁇ g) per milligram PLGA could be achieved.
• mTHPC loaded (incorporated) nanoparticles were characterized and lyophilized as described within example 1 a.
• HT29 cells were cultured on glass slides (BD Biosciences GmbH, Heidelberg) and incubated with the nanoparticulate formulation for 4h at 37°C. Following, the cells were washed twice with PBS and the membranes were stained with Concanavalin A AlexaFluor350 (5( ⁇ g/ml; Invitrogen, Düsseldorf) for 2 min. Cells were fixed with 0.4 % paraformaldehyde for 6 min. After fixation, the ceils were washed two times and embedded in Vectashield HardSet Mounting Medium (Axxora, Grunberg).
• the microscopy analysis was performed with an Axiovert 200 M microscope with a 510 NLO Meta device (Zeiss, Jena), a chameleon femtosecond or an argon ion laser and the LSM Image Examiner software.
• the green fluorescence of the PLGA based nanoparticles leading from incorporated Lumogen Yellow (R) (BASF; Ludwigshafen) and the red autofluorescence of the photosensitizer 5, 10, 10,20-tetrakis(3-hydroxyphenyl)-porphyrin (mTHPP) was used to determine the distribution.
• Figures 4A and B shows the cellular uptake/adhesion and intracellular distribution of PLGA based nanoparticles with the photosensitizer 5, 10, 1 ,20-tetrakis(3-hydroxyphenyl)- porphyrin (mTHPP) studied by confocal laser scanning microscopy.
• HT29 cells were cultured on glass slides and incubated with the nanoparticles for 4 h at 37°C. The red autofluorescence of the photosensitizer mTHPP was used.
• the nanoparticles contain incorporated Lumogen Yellow (R) (green).
• Figures 5A and B shows the cellular uptake/adhesion and intracellular distribution of PLGA based nanoparticles with the photosensitizer 5, 10, 10,20-tetrakis(3-hydroxyphenyl)- chlorin (mTHPC) studied by confocal laser scanning microscopy.
• HT29 cells were cultured on glass slides and incubated with the nanoparticles for 4 h at 37°C. The red autofluorescence of the photosensitizer mTHPC was used.
• the nanoparticles contain incorporated Lumogen Yellow (R) (green).
• Figure 6 shows the results of phototoxicity of 3 ⁇ mTHPC, and different mTHPC loaded PLGA nanoparticles on Jurkat cells after different incubation times. Left: Rate of apoptosis, Right: Rate of necrosis, (reference ceils were incubated and irradiated without photosensitizer).
• Figure 7 shows the results of intracellular uptake of 3 ⁇ mTHPC, and different mTHPC loaded PLGA nanoparticles by Jurkat cells after different incubation times. The experiments were repeated twice and for each measurement the cell number was counted three times to get an average. Error bars represent the standard deviation of six measurements
• the mTHPC concentration in the ethanol extract was determined via fluorescence using a standard fluorescence series.
• the diameter of the cells was assumed to be 10 ⁇ m (3 measurements).
• All three PLGA-nanoparticles transport mTHPC into the cells.
• the transport into the cells occurs in a faster way, when the mTHPC is incorporated in the NPs.

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