WO2005102284A1

WO2005102284A1 - Protein-containing lipid implant for sustained delivery and its preparation method

Info

Publication number: WO2005102284A1
Application number: PCT/KR2005/001111
Authority: WO
Inventors: Hee Yong Lee; Sung Kyu Kim; Jung Soo Kim; Young Hwan Jung; Jung In Kim; Yun Mi Seo; Ji Suk Lee; Eun Young Seol; Seung Gu Chang; Ho Il Choi
Original assignee: Peptron Co., Ltd
Priority date: 2004-04-20
Filing date: 2005-04-19
Publication date: 2005-11-03
Also published as: KR100486028B1

Abstract

Disclosed are a protein-containing lipid implant for sustained delivery, which comprises a compressed mixture of a protein drug coated with a hydrophilic polymer and a lipid, and a method of preparing the lipid implant. The protein-containing lipid implant for sustained delivery sustains the in vivo release of a protein drug in an active state for a long period of time because the protein drug is evenly distributed in a lipid matrix in a stable state, and thus maintains constant serum levels of the protein drug. Thus, the lipid implant is capable of effectively treating diseases and reducing injection frequency.

Description

PROTEIN-CONTAINING LIPID IMPLANT FOR SUSTAINED DELIVERY AND ITS PREPARATION METHOD

Technical Field

The present invention relates to a protein-containing lipid implant for sustained delivery, which comprises a compressed mixture of a protein drug coated with a hydrophilic polymer and a . lipid and is capable of continuously and homogeneously releasing a protein drug into the body while maintaining the biological activity of the protein drug in vivo.

Background Art

A majority of protein drugs, when orally administered, lose their active structures in the acidic environment of the stomach or are destroyed by enzymatic degradation in the stomach, and are absorbed in very low levels through the mucous membrane of the stomach and the intestine. For this reason, most protein drugs are administered parenterally, that is, by intravenous injection, subcutaneous injection or intramuscular injection. Even after being administered via these routes, most protein drugs must be repeatedly injected due to their short half-lives in vivo. In particular, since protein drugs are often required to be administered for a long period of several months, many studies have been conducted to develop sustained-release formulations using biodegradable polymers [see, Heller, J. et al . , Controlled release of water-soluble macromolecules from biodegradable hydrogels, Biomaterials , 4, 262-266 (1983); Langer, R., New methods of drug delivery, Science, 249, 1527-1533 (1990)]. The most commonly used biodegradable polymers lor sustained-release formulations of protein drugs are polyesters as synthetic polymers, which include polylactide (PLA) , polyglycolide (PGA) , and their copolymer, poly (lactide-co-glycolide) (PLGA) [see, DeLuca, P. P. et al . ,

Biodegradable polyesters for drug and polypeptide delivery, in: El-Nokaly, M. A., Piatt, D. M., and Charpentier, B. A. (Eds.), Polymeric delivery systems, properties and applications, American Chemical Society, pp. 53-79 (1993); Park, T. G., Degradation of poly (lactic-co-glycolic acid) microspheres : effect of copolymer composition, Biomaterials, 16, 1123-1130 (1995); Anderson, J. M. and Shive, M. S., Biodegradation and biocompatibility of PLA and PLGA microspheres, Adv. Drug. Del . Rev. , 28, 5-24 (1997); Tracy, M. A. et al . , Factors affecting the degradation rate of poly (lactide-co-glycolide) microspheres in vivo and in vitro, Biomaterials, 20, 1057-1062 (1999)]. In addition to these synthetic polyesters, natural polymers have been studied as matrices for sustained-release formulations of protein drugs . The natural polymers include lipid substances such as lipids, fatty acids, waxes and their derivatives; proteins such as albumin, gelatin, collagen and fibrin; and polysaccharides such as alginic acid, chitin, chitosan, dextran, hyaluronic acid and starch. U.S. Pat. ^'No. 4,880,839 describes an active drug, such as aminofilin, teofilin, hydroxyzine, chlorodiazepoxide, chloropromazine hydrochloride, morphine and propranolol, which is prepared in a multiple-matrix sustained-release formulation capable of maintaining the activity of an active compound for a long period of time using a water-soluble/dispersible matrix, such as polysaccharides, alginate and gelatin, as a sustained- release matrix. When the water-soluble materials, such as proteins or polysaccharides among the polymers, are used as matrices, the sustained release of protein drugs for a period of several days or weeks is very difficult to achieve. In contrast, since synthetic polyesters or lipids are water-insoluble, they are able to provide the sustained release of protein drugs for a period of several days, weeks or months. Protein drugs can be trapped in polymeric matrices of polyesters, such as polylactide (PLA) or poly (lactide-co- glycolide) (PLGA) , using coacervation or emulsion phase separation, encapsulation by spray drying, solvent evaporation in an organic or water phase, and the like [see, McGee, J. P. et al . , Zero order release of protein from poly (D,L-lactide-co-glycolide) microparticles prepared using a modified phase separation technique, J. Controlled Rel . , 34, 77-86 (1995); Gander, B. et al . , Quality improvement of spray-dried, protein-loaded D,L-PLA microspheres by appropriate polymer solvent selection, J. Microencapsul . , 12, 83-97 (1995); O'Donnell, P. B. and McGinity, J. W., Preparation of microspheres by the solvent evaporation technique, Adv. Drug Del . Rel . , 28, 25-42 (1997)]. Among the above methods, W/O/W (or double emulsion- solvent evaporation) has been widely used in manufacturing sustained release microparticles containing protein drugs because most protein drugs are water-soluble. In this W/O/W technique, a protein or water-soluble drug is dissolved in water, and this aqueous phase is dispersed in an organic phase containing a biodegradable polymer using an ultrasonicator or homogenizer to give a primary emulsion. This primary emulsion is again dispersed in a secondary aqueous phase containing a surfactant such as polyvinylalcohol to provide a secondary emulsion. As the organic solvent is removed from this system by heating or under reduced pressure, the polymer is solidified to form microparticles. The microparticles are recovered by centrifugation or filtration and freeze-dried to yield biodegradable microparticles containing the protein or water-soluble drug. However, during the microencapsulation process, protein denaturation and irreversible aggregation occur under harsh conditions such as sonication or homogenization when the protein drug is located in the interface between the aqueous phase and the organic solvent. From the microparticles thus obtained, the protein is initially released in an excessive amount of several tens of percentages of the entire drug, rarely released for a subsequent period of several days to several tens ^' of days, and released at a slightly increased rate at late stages [see, Kim, H. K. and Park, T. G., Biotechnol . Bioeng. 65, 659-667 (1999); Crotts, G. and Park, T. G., J. Microencapsul . , 15, 699-713 (1998)]. Many studies have been made to minimize protein denaturation and irreversible aggregation when proteins are entrapped into polyester matrix. In one strategy, a stabilizer may be used in an aqueous solution of a protein, which is exemplified by trehalose, mannitol, dextran and polyethylene glycol, and has been reported to stabilize proteins to some extent [see, U.S. Pat. No. 5,804,557; Cleland, J. L. and Jones, A. J. S., Pharm. Res . , 13, 1464- 1475 (1996); Cleland, J. L. et al . , Pharm. Res . , 14, 420-425 (1997); Pean, J. M. et al . , Pharm. Res . , 16, 1294-1299 (1999); Sanchez, A. et al . , Int . J. Pharm. , 185, 255-266 (1999); Lavelle, E. C. et al . , Vaccine, 17, 516-529 (1999)]. These stabilizers form a hydrated layer around a protein and thus reduce the interaction between a protein and an organic solvent, thereby preventing denaturation and irreversible aggregation of the protein to some extent. In addition, the protein denaturation may be minimized by directly dispersing a protein drug in an organic solvent in the form of particulate in a homogeneous state rather than in the form of being dissolved in an aqueous solution [see, Cleland, J. L. and Jones, A. J. S., Stable formulations of recombinant human growth hormone and interferon-γ for microencapsulation in^< biodegradable microspheres, 13, 1464- 1475 (1996); Iwata, M. et al., Particle size and loading efficiency of poly (D,L-lactic-co-glycolic acid) multiphase microspheres containing water soluble substances prepared by the hydrous and anhydrous solvent evaporation methods, J. Microencapsul . , 16, 49-58 (1999)]. Recently, using the method employing protein particles among the aforementioned methods, human growth hormone was encapsulated into poly (lactide-co-glycolide) . The thus obtained formulation for the sustained release of human growth hormone (hGH) was approved by the U.S. Food and Drug Administration under the trade name "Lutropin Depot™" . This hGH sustained release microsphere formulation is prepared by dispersing particles of hGH stabilized in a complex with a metal cation (Zn²⁺) in a polymer solvent, such as methylene chloride, in which poly (lactide-co-glycolide) is dissolved, spraying the dispersion in liquid nitrogen containing ethanol, and removing the methylene chloride solvent at low temperature using the ethanol, thereby minimizing the denaturation of the protein drug during the manufacturing process [see, U.S. Pat. Nos. 5,019,400 and 5,654,010]. However, a recent report revealed that this sustained release formulation has very low protein bioavailability (33-55%) compared to daily injection formulation [see, Cleland, J. L. et al . , Emerging protein delivery methods, Current Opinion in Biotechnology, 12, 212-210 (2001) . This low protein bioavailability of Lutropin Depot™ may be due to the very high initial burst of human growth hormone, or due to the very slow in vivo degradation (several weeks or several months) of the polymer used, poly (lactide-co-glycolide) , thereby causing the protein not to be released for a long period of time after being administered into the body and eventually resulting in the denaturation of the protein. As demonstrated in the aforementioned reports, at present, protein drugs are technically very difficult to provide as sustained release formulations in which the protein drugs are stably encapsulated into polymeric matrices of polyesters and released for a sustained period of several days, several weeks or more without high initial bursts . Unlike the synthetic polyesters that have been much studied for their use in sustained release formulations of protein drugs, lipid substances, including lipids, fatty acids, waxes and derivatives thereof, have not been sufficiently studied for their use in sustained release formulations of protein drugs . The lipids have many advantages in that they are mostly substances present in the body and thus -have good biocompatibility, are available in several types having diverse physical properties such as molecular weight, solubility in solvents, hydrophobicity and electric nature, and have varying in vivo absorption rates when injected subcutaneously or intramuscularly. However, lipid substances have the following problems: strong interaction between lipids and proteins, denaturation of protein drugs due to such interaction, difficulty in control of protein drug release rate, and the like. For these problems, the lipids have not been successfully used in sustained release formulations of protein drugs . Although many studies have been made to develop sustained release formulatipns of protein drugs using liposomes that are artificial biological membranes comprising phospholipids as a major component, such formulations have not been commercialized due to problems in stability of formulations and protein drugs. Lipid implant formulations for the sustained release of proteins began to be studied in the late 1980' s using model drugs such as insulin and animal growth hormones . Paul Yao-Cheng Wang reported in U.S. Pat. No. 5,939,380 that when insulin is prepared in a disc or pellet form using lipids such as fatty acids, cholesterol and triglyceride, it has an effect of lowering blood glucose levels for a period of 20-40 days in an animal test with male Wistar rats, thereby suggesting that such a lipid implant preparation can be used as a sustained release formulation for protein drugs . In this patent, solid protein particles such as insulin or porcine growth hormone are homogeneously admixed with a lipid powder in a suitable ratio, and the resulting admixture is compressed into a disc form to yield a lipid implant preparation. In an animal test, the hypoglycemic effect of insulin lasts for a period of 20-40 days. However, as described in the patent, since insulin was administered in a large enough dosage to reduce hyperglycemia for 40-80 days, a majority of the administered insulin is believed to be denatured by the lipid material used as a matrix or not to be completely released from the matrix due to its strong interaction with lipids. These results suggest that a protein drug must be technically and stably protected from a lipid matrix when prepared in a sustained release formulation in which the protein drug is evenly distributed in the lipid matrix. U.S. Pat. No. 5,750,100 discloses an implant preparation for protein drugs, which is prepared using an artificially synthesized polyglycerol fatty acid ester as a matrix. The polyglycerol fatty acid ester used in this patent is able to increase the stability of protein drugs due to its high hydrophilicity relative to natural lipids such as fatty acids and glycerides. However, the matrix material is problematic in terms of being very slowly degraded and absorbed when administered into the body, leading to an increase in protein denaturation. The present inventors have found that a sustained release lipid implant preparation comprising a protein drug, in which protein solid particles stabilized using a hydrophilic polymer are evenly distributed in a lipid matrix and compressed, slowly releases the protein drug at consistent rates for a long period of time without denaturation and high initial burst of the protein drug.

Disclosure of the Invention

The present invention relates to a protein-containing lipid implant for sustained delivery, comprising a compressed mixture of a protein drug coated with a hydrophilic polymer and a lipid. The hydrophilic polymer, used in the preparation of the protein drug coated with the hydrophilic polymer, preferably has a molecular weight of more than 2,000 daltons, and is selected from polyethylene glycol, polyvinylpyrrolidone, polyvinylalcohol, polyethyleneimine, dextran, dextran sulfate, chondroitin sulfate, dermatan sulfate, heparan sulfate, keratan sulfate, hyaluronic acid, chitosan, albumin, collagen, fibrin, and mixtures thereof. The lipid, which is mixed with the protein drug coated with the hydrophilic polymer and compressed, is preferably solid at room temperature, and is selected from fatty acids, monoglycerides, diglycerides, triglycerides, sorbitan fatty acid esters, phospholipids, sphingolipids, waxes, and salts and derivatives thereof. The protein drug coated with the hydrophilic polymer preferably includes an additional protein stabilizer. The protein stabilizer is preferably selected from sugars, polyols, surfactants, amino acids, inorganic salts and mixtures thereof. The content of the hydrophilic polymer in the protein drug coated with the hydrophilic polymer ranges from 0.1 to 99.9 wt%. The content of the lipid substance in the protein- containing lipid implant for sustained delivery ranges from 40 to 99 wt%. The protein-containing lipid implant for sustained delivery according to the present invention is preferably in a disc, pellet or rod form, or in a microparticle or powder form obtained therefrom by spheronization, milling, grinding, or the like. In addition, the present invention relates to a method of preparing a protein-containing lipid implant for sustained delivery, comprising coating a protein drug with a hydrophilic polymer to yield a solid protein powder, mixing the coated solid protein powder with a lipid, and compressing or extruding the mixture to be formulated into a pharmaceutical dosage form. The solid protein powder coated with the hydrophilic polymer is 0.1 μm to 200 μm in diameter. The solid protein powder coated with the hydrophilic polymer is prepared by dissolving protein molecules and a hydrophilic polymer and drying the resulting solution by a method selected from spray drying, freeze drying, spray freeze drying and bubble drying. Alternatively, the solid protein powder coated with the hydrophilic polymer is prepared by dispersing protein microparticles in a solution in which a hydrophilic polymer is dissolved and drying the resulting dispersion by a method selected from spray drying, freeze drying, spray freeze drying and bubble drying. The protein microparticles .are prepared by drying an aqueous solution in which a protein is dissolved by a method selected from spray drying, freeze drying, spray freeze drying and bubble drying. When the solid protein powder coated with the hydrophilic polymer is prepared, an additional protein stabilizer is preferably added. The additional protein stabilizer is preferably selected from sugars, polyols, surfactants, amino acids, inorganic salts and mixtures thereof. The sugars used as the additional protein stabilizer are preferably selected from sucrose, glucose, inositol, trehalose, maltose, mannitol, lactose, mannose, xylitol, sorbitol and cyclodextrin.

Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: FIGS, la to lc are chromatograms obtained by reverse phase HPLC of interferon alpha, which show the protein stability in an interferon alpha-containing sustained release preparation according to the present invention after manufacture of the preparation and during drug release; FIGS. 2a to 2d show the in vivo release profiles of an interferon alpha-containing sustained release preparation and comparative preparations; FIGS. 3a to 3e are size exclusion/ reverse phase HPLC chromatograms showing the protein denaturation in an interferon alpha-containing sustained release preparation; FIGS. 4a and 4b are microscopic photographs of a surface and a cross-section of an interferon alpha- containing sustained release preparation according to the present invention; FIG. 5 is a microscopic photograph of an interferon alpha-containing preparation prepared by melting and dispersion in Comparative Example 7; and FIG. 6 is a microscopic photograph of a surface of an interferon alpha-containing preparation prepared by melting and cooling in Comparative Example 8.

Best Mode for Carrying Out the Invention

In one aspect, the present invention provides a protein-containing lipid implant for sustained delivery, comprising a compressed mixture of a protein drug coated with a hydrophilic polymer and a lipid. The term "protein drug", as used herein, includes a drug containing a protein or peptide, or a major ingredient thereof. With respect to the objects of the present invention, a "protein" capable of being contained in the protein-containing lipid implant of the present invention includes a biologically active protein or peptide, or derivatives and mutants thereof, and may be naturally occurring, recombinantly manipulated or synthesized. Also, the protein may possess a variety of modifications, such as an addition, substitution, or deletion of an amino acid or domain, or glycosylation, and is not specifically limited. Non-limiting examples of protein drugs include human growth hormone, growth hormone releasing hormone, growth hormone releasing peptide, interferons, colony stimulating factors, interleukins, macrophage activating factor, macrophage peptide, B cell factor, T cell factor, protein A, allergy inhibitor, cell necrosis glycoproteins, immunotoxin, lymphotoxin, tumor necrosis factor, tumor suppressors, metastasis growth factor, alpha-1 antitrypsin, albumin and fragment polypeptides thereof, apolipoprotein- E, erythropoietin, factor VII, factor VIII, factor IX, plasminogen activating factor, urokinase, streptokinase, protein C, C-reactive protein, renin inhibitor, collagenase inhibitor, superoxide dismutase, platelet-derived growth factor, epidermal growth factor, osteogenic growth factor, bone stimulating protein, calcitonin, insulin, atriopeptin, cartilage inducing factor, connective tissue activating factor, follicle stimulating hormone, luteinizing hormone, luteinizing hormone releasing hormone, nerve growth factors, parathyroid hormone, relaxin, secretin, somatomedin, insulin-like growth factor, adrenocortical hormone, glucagon, cholecystokinin, pancreatic polypeptide, gastrin releasing peptide, corticotropin releasing factor, thyroid stimulating hormone, monoclonal or polyclonal antibodies against various viruses, bacteria, toxins, etc., and virus-derived vaccine antigens. Preferred are human serum albumin, human growth hormone, interferon alpha, erythropoietin, colony stimulating factors, etc. The "hydrophilic polymer" used in the lipid implant of the present invention is a polymeric substance that surrounds the surface of protein particles contained in the lipid implant and is stably present between hydrophobic lipid molecules. This hydrophilic polymer protects and stabilizes protein particles, prevents protein denaturation, and induces the stable release of the protein particles in all processes until the protein particles are released in vivo. The protein particles are released when the lipid is exposed to body fluids, dissolved, and degraded or absorbed. The hydrophilic polymer prevents a protein drug from being denatured during the preparation of the lipid implant as well as during drug release after the lipid implant is administered into the body. Also, the hydrophilic polymer protects a protein drug against degradation and aggregation as well as against denaturation, enhances the in vivo activity of the protein drug, and maintains the sustained release of the protein drug. In studies involving the use of hydrophilic polymers, some efforts have been made to merely physically εdd polyethylene glycol or to use a polyester polymer covalently bonded to polyethylene glycol as a matrix when a sustained release formulation containing a protein drug is prepared using a hydrophilic polymer such as a polyester [see, Schwendeman, S. P., Recent advances in the stabilization of proteins encapsulated in injectable PLGA delivery systems, Critical Reviews in Therapeutic Drug Carrier Systems, 19, 71-98(2002)]. However, there is no report describing a method of preparing a protein- containing lipid implant for sustained delivery, as described in the present invention, by coating protein particles with a hydrophilic polymer such as polyethylene glycol to yield a stabilized protein powder, mixing the protein powder with a lipid substance and compressing the mixture. In a preferred aspect, the present invention employs, as the hydrophilic polymer, a substance having a molecular weight of more than about 2,000 daltons, which is selected from the group consisting of polyethylene glycol, polyvinylpyrrolidone, polyvinylalcohol, polyethyleneimine, dextran, dextran sulfate, chondroitin sulfate, dermatan sulfate, heparan sulfate, keratan sulfate, hyaluronic acid, chitosan, albumin, collagen, fibrin, and mixtures thereof. Preferred is polyethylene glycol, hyaluronic acid, dextran, dextran sulfate, chondroitin sulfate, dermatan sulfate, keratan sulfate or heparan sulfate. Most preferred is polyethylene glycol or dextran. The term "lipid implant", as used herein, refers to an implant that is used as a matrix for the transport of an active drug. The lipid implant preferably has an injectable size, but, if desired, may be inserted at an administration site by surgical operation. With respect to the objects of the present invention, the protein-containing lipid implant for sustained delivery according to the present invention is in a disc, pellet or rod form, or in a microparticle or powder form obtained therefrom by spheronization, milling, grinding, and the like. The "lipid", used in the protein- containing lipid implant for sustained delivery according to the present invention, is a water-insoluble substance that is absorbed by the body, does not have side effects and is solid at room temperature. Preferred examples of lipids include, but are not limited to, fatty acids, monoglycerides, diglycerides, triglycerides, sorbitan fatty acid esters, phospholipids, sphingolipids, cholesterol, waxes, and salts and derivatives thereof. More preferably, available fatty acids include lauric acid, myristic acid, palmitic acid and stearic acid. Available monoglycerides include glyceryl laurate, glyceryl myristrate, glyceryl palmitate and glyceryl stearate. Available sorbitan fatty acid esters include sorbitan myristrate, sorbitan palmitate and sorbitan stearate. Available triglycerides include trilaurin, trimyristin, tripalmitin and tristearin. Available phospholipids include phosphatidylcholine, phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylglycerol, phosphatidylinositol and cardiolipin. Available sphingolipids include sphingosine, ceramide and sphinganine . The lipid used in the protein-containing lipid implant for sustained delivery according to the present invention is particularly preferably trilaurin, lauric acid, palmitic acid, stearic acid, glyceryl monostearate or glyceryl myristrate. The protein drug coated with a hydrophilic polymer, contained in the protein-containing lipid implant for sustained delivery according to the present invention, may include an additional protein stabilizer. Examples of the additional protein stabilizer may include sugars including sucrose, glucose, inositol, trehalose, maltose, mannitol, lactose, mannose, xylitol, sorbitol, cyclodextrin and glycerol, polyols, surfactants, amino acids, inorganic acids, and mixtures thereof. Particularly preferred examples of the additional stabilizer, used in the preparation of the solid protein powder stabilized by a hydrophilic polymer, include trehalose, mannitol, glycine, and zinc chloride. In addition, if desired, the lipid matrix may include ingredients commonly used in the preparation of solid pharmaceutical preparations, which are exemplified by an excipient, a binder, a disintegrator and a preservative. Examples of preservatives include paraoxybenzoic acid ester, benzyl alcohol, chlorobutanol and timerosal. The protein drug, contained in the protein-containing lipid implant for sustained delivery according to the present invention, is stabilized by a hydrophilic polymer. The hydrophilic polymer is contained in the protein drug stabilized by the hydrophilic polymer in an amount of about 0.1-99.9 wt%, and preferably about 50-95 wt% . The lipid substance is contained in the protein- containing lipid implant for sustained delivery according to the present invention in an amount of about 40-99 wt%, and preferably about 60-95 wt%. In another aspect, the present invention provides a method of preparing a protein-containing lipid implant for sustained delivery, comprising coating a protein drug with a hydrophilic polymer to yield a solid protein powder, mixing the coated solid protein powder with a lipid, and compressing or extruding the mixture to be formulated into a pharmaceutical dosage form. The solid protein powder coated with the hydrophilic polymer may be prepared by homogeneously dissolving protein molecules and a hydrophilic polymer and drying the resulting solution by spray drying, freeze drying, spray freeze drying, bubble drying, or the like. Alternatively, the solid protein powder coated with the hydrophilic polymer may be prepared by dispersing protein microparticles in a solution in which a hydrophilic polymer is dissolved and drying the resulting dispersion by spray drying, freeze drying, spray freeze drying, bubble drying, or the like. The protein microparticles, used in the preparation of the solid protein powder coated with a hydrophilic polymer, may be prepared by drying an aqueous solution in which protein molecules are dissolved by spray drying, freeze drying, spray freeze drying, bubble drying, or the like. For example, when a spray drying method is used, a solution in which a protein is dissolved, a solution in which a protein and a hydrophilic polymer are dissolved, or a dispersion of protein microparticles in a solution in which a hydrophilic polymer is dissolved may be supplied to a spray dryer (e.g., Buchi-191) , having a drying air temperature of 55-140°C and a flow rate of about 1.0-5.0 ml/min, and spray-dried using the spray dryer. Also, when a freeze drying method is used, a solution in which a protein is dissolved or a solution in which a protein and a hydrophilic polymer are dissolved may be freeze-dried at - 70°C. The resulting freeze-dried product may be ground, and particles having a predetermined size (e.g., less than 50 μm) may be isolated from the freeze-dried product. Upon the preparation of the protein-containing lipid implant for sustained delivery according to the present invention, an additional protein stabilizer may be added at the step of preparing the solid protein powder coated with a hydrophilic polymer or at the step of preparing the protein microparticles. Examples of the protein stabilizer include sugars, polyols, surfactants, amino acids, inorganic acids, and mixtures thereof. Examples of preferred sugars include sucrose, glucose, inositol, trehalose, maltose, mannitol, lactose, mannose, xylitol, sorbitol and cyclodextrin. Examples of particularly preferred additional stabilizers, used in the preparation of the solid protein powder stabilized by a hydrophilic polymer, include trehalose, mannitol and glycine . The solid protein powder coated with a hydrophilic polymer, prepared according to the aforementioned method, is about 0.1-200 μm, and preferably about 2-50 μm in diameter. In the present method, a mixture of a solid protein powder stabilized by a hydrophilic polymer and a lipid substance is formulated into a disc, pellet or rod form by compression, extrusion, or the like under conditions in which a protein drug is not denatured, for example, a pressure of 0.01-50 tons and a temperature of 0-80°C for less than 5 minutes . Preferably, when a tableting machine is used, tableting may be carried out at a pressure of 1-10 tons for 0.1-60 seconds. When an extruder is used, extrusion may be carried out at a pressure of 0.1-5 tons and 0-50°C for 1-60 seconds. Formulation conditions may be optimized to minimize protein denaturation according to protein properties. Also, if the protein is not denatured even when the lipid is molten, a formulation can be obtained under pressure. A lipid implant preparation for sustained release may be prepared by homogeneously mixing protein particles coated with a hydrophilic polymer or protein particles coated with a hydrophilic polymer including an additional stabilizer with a lipid substance, and formulating the mixture into a disc or pellet using a tableting machine or a compressor having a suitable mold, or formulating the mixture into a rod using an injector or and extruder. In the present invention, the protein particles and the lipid substance are homogeneously mixed in solid states, unlike a conventional formulation prepared by mixing protein particles with a melted lipid. After the conventional formulation is transplanted, a protein drug is released ar once or is rarely released due to denaturation of protein by high temperature and disrupt of the uniform and dense structure of the matrix. For example, a mixture of a solid protein powder and a lipid may be compressed into a disc form, as follows. The mixture may be placed in a 13-mm KBr die and compressed into a disc at a pressure of 0.4 ton for 1 min using a carver laboratory press. Also, when the mixture is extruded to a rod form, the mixture may be extruded to a rod 1^" mm thick at a pressure of 0.4 ton at 37°C using a ram-type extruder . FIG. 6 is a microscopic photograph of a surface of a rod preparation prepared by melting and cooling in Comparative Example 8. As shown in FIG. 6, when a preparation is prepared only by melting and cooling, it has a highly porous surface and thus^" does not have a sustained release property. In contrast, as shown in FIGS. 4a and 4b which are microscopic photographs of a surface and a cross- section of a rod preparation prepared by extrusion according to the present invention, when a solid protein powder and a lipid are mixed in solid states and compressed, a protein drug is evenly distributed in the lipid matrix. This is consistent with the result of an in vivo release test in that a protein-containing lipid implant preparation according to the present invention, prepared by applying pressure to a mixture of a solid protein powder protected by a hydrophilic polymer and a lipid, displays a sustained release property. The protein-containing lipid implant preparation for sustained delivery according to the present invention is formulated into a disc, pellet or rod form. The resulting disc or pellet is, for example, cut into a suitable size of 0.5-1.5 mm thick, 1-5 mm wide and 1-10 mm long according to its dosage and subcutaneously inserted. The rod is cut into a suitable size of 0.5-1.0 mm in diameter and 5-15 mm in length according to its dosage, inserted into a syringe needle, and subcutaneously inserted using a syringe having a piston fitted into the needle. In another method, protein particles coated with a hydrophilic polymer are suspended in a solvent in which a lipid is dissolved, and the suspension is spray-dried to yield lipid-coated microparticles. The microparticles are placed in a pressure tank, and pressure is applied to the microparticles to obtain a desired pharmaceutical dosage form. Alternatively, a microparticle or powder preparation is obtained from a disc, pellet or rod by spheronization, milling, grinding, or the like. A better understanding of the present invention may be obtained through the following examples and test examples which are set forth to illustrate, but are not to be construed as the limit of the present invention. Methods of preparing protein particles or stabilizer- containing protein particles are provided in an illustrative manner in Examples 1 to 17.

EXAMPLE 1 : Preparation of human serum albumin microparticles by spray drying

Human serum albumin and trehalose were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human serum albumin microparticles. Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 3 urn in average diameter.

EXAMPLE 2: Preparation of human serum albumin microparticles by spray drying

Human serum albumin and mannitol were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human serum albumin microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 3 : Preparation of human serum albumin microparticles by freeze drying Human serum albumin was dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 4 : Preparation of human growth hormone microparticles by spray drying

Human growth hormone was dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone microparticles . Herein, drying air at 92°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 5: Preparation of human growth hormone microparticles by spray drying

Human growth hormone and zinc chloride were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 0.01 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone microparticles . Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 6: Preparation of human growth hormone microparticles by spray drying

Human growth hormone and trehalose were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 5 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone microparticles . Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 7 : Preparation of human growth hormone microparticles by freeze drying

Human growth hormone and mannitol were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at

10 mg/ml and 5 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen- Bradley, USA) .

EXAMPLE 8 : Preparation of interferon alpha microparticles by spray drying

Interferon alpha and trehalose were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 5 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 9: Preparation of interferon alpha microparticles by spray drying Interferon alpha and glycine were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 4 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 4 μm in average diameter.

EXAMPLE 10: Preparation of interferon alpha microparticles by spray drying ^■

Interferon alpha, trehalose and glycine were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 2 mg/ml, 7 mg/ml and 41 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of

3.0 ml/min, thereby yielding interferon alpha microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were

3 μm in average diameter. EXAMPLE 11: Preparation of interferon alpha microparticles by spray drying

Interferon alpha and zinc chloride were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 0.06 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 12 : Preparation of interferon alpha microparticles by freeze drying

Interferon alpha and trehalose were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 5 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 13: Preparation of interferon alpha microparticles by freeze drying Interferon alpha and mannitol were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 9 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 14: Preparation of erythropoietin (EPO) microparticles by spray drying

Erythropoietin, trehalose and glycine were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml, 5 mg/ml and 4 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 2.5 ml/min, thereby yielding EPO microparticles . Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 15: Preparation of granulocyte colony stimulating factor (G-CSF) microparticles by spray drying

Granulocyte colony stimulating factor (G-CSF) and zinc chloride were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 0.06 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding G-CSF microparticles . Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 3 urn in average diameter.

EXAMPLE 16: Preparation of erythropoietin microparticles by freeze drying

Erythropoietin and trehalose were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 5 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 17: Preparation of G-CSF microparticles by freeze drying

G-CSF and mannitol were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 9 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

Methods of preparing protein particles protected by a hydrophilic polymer using spray drying, freeze drying and bubble drying are provided in an illustrative manner in Examples 18 to 63. EXAMPLE 18 : Preparation of human serum albumin-containing polyethylene glycol microparticles by spray drying

Human serum albumin and polyethylene glycol (MW: 10,000) were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human serum albumin-containing polyethylene glycol microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 19: Preparation of human serum albumin-containing polyethylene glycol microparticles by spray drying

Human serum albumin and polyethylene glycol (MW: 3,350) were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human serum albumin-containing polyethylene glycol microparticles . Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 20: Preparation of human serum albumin-containing polyethylene glycol microparticles by spray drying

The human serum albumin microparticles prepared in Example 1 were homogeneously dispersed at 5 mg/ml in a solution prepared by dissolving polyethylene glycol (MW: 3,350) in methylene chloride at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human serum albumin-containing polyethylene glycol microparticles. Herein, drying air at 55°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 21: Preparation of human serum albumin-containing methylcellulose microparticles by spray drying

Human serum albumin and methylcellulose were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 5 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human serum albumin-containing methylcellulose microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 22 : Preparation of human serum albumin-containing hyaluronic acid microparticles by spray drying Human serum albumin and hyaluronic acid were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, and supplied to a spray dryer (Buchi- 191) at a flow rate of 2.5 ml/min, thereby yielding human serum albumin-containing hyaluronic acid microparticles . Herein, drying air at 100°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 23: Preparation of human serum albumin-containing dextran microparticles by freeze drying

Human serum albumin and dextran (MW: 70,000) were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at

10 mg/ml and 90 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen- Bradley, USA) .

EXAMPLE 24 : Preparation of human serum albumin-containing polyethylene glycol microparticles by freeze drying Human serum albumin and polyethylene glycol (MW:

10,000) were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 90 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 25: Preparation of human serum albumin-containing polyethylene glycol microparticles by freeze drying

Human serum albumin and polyethylene glycol (MW:

3,350) were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 90 mg/ml, respectively, frozen at

-70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 26: Preparation of human serum albumin-containing dextran polyethylene glycol microparticles by freeze drying

Human serum albumin, dextran (MW: 70,000) and polyethylene glycol (MW: 3,350) were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, 10 mg/ml and 90 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 27 : Preparation of human serum albumin-containing carboxymethylcellulose microparticles by freeze drying

Human serum albumin and carboxymethylcellulose were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 20 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 urn in diameter were separated using a sonic sifter (Allen- Bradley, USA) .

EXAMPLE 28: Preparation of human growth hormone-containing dextran microparticles by spray drying

Human growth hormone and dextran (MW: 70,000) were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 5 mg/ml and 25 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing dextran microparticles. Herein, drying air at 100°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 29: Preparation of human growth hormone-containing polyethylene glycol microparticles by spray drying

Human growth hormone, zinc chloride and polyethylene glycol (MW: 10,000) were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, 0.01 mg/ml and 10 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing polyethylene glycol microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 4 urn in average diameter.

EXAMPLE 30: Preparation of human growth hormone-containing polyethylene glycol microparticles by spray drying

Human growth hormone and polyethylene glycol (MW: 3,350) were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing polyethylene glycol microparticles . Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 31: Preparation of human growth hormone-containing carboxymethylcellulose microparticles by spray drying Human growth hormone and carboxymethylcellulose were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 20 mg/ml, respectively, and ( supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing carboxymethylcellulose microparticles. Herein, drying air at 98°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 32 : Preparation of human growth hormone-containing methylcellulose microparticles by spray drying

Human growth hormone and methylcellulose were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 5 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing methylcellulose microparticles. Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 3 urn in average diameter.

EXAMPLE 33 : Preparation of human growth hormone-containing dextran sulfate microparticles by spray drying

Human growth hormone and dextran sulfate (MW: 25,000) were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 10 mg/ml and 50 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 2.5 ml/min, thereby yielding human growth hormone-containing dextran sulfate microparticles. Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 34: Preparation of human growth hormone-containing chondroitin sulfate microparticles by spray drying Human growth hormone and chondroitin sulfate were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing chondroitin sulfate microparticles. Herein, drying air at 92°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 35: Preparation of human growth hormone-containing dermatan sulfate microparticles by spray drying Human growth hormone and dermatan sulfate were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing dermatan sulfate microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 36: Preparation of human growth hormone-containing keratan sulfate microparticles by spray drying

Human growth hormone and keratan sulfate were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 10 mg/ml and 20 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing keratan sulfate microparticles. Herein, drying air at 93°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 37 : Preparation of human growth hormone-containing heparan sulfate microparticles by spray drying

Human growth hormone and heparan sulfate were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 10 mg/ml and 30 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing heparan sulfate microparticles. Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 4 μm in average diameter.

EXAMPLE 38 : Preparation of human growth hormone-containing polyethylene glycol microparticles by freeze drying Human growth hormone and polyethylene glycol (MW:

10,000) were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 10 mg/ml and 20 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 39: Preparation of human growth hormone-containing polyethylene glycol microparticles by freeze drying

Human growth hormone and polyethylene glycol (MW: 3,350) were dissolved in 10 mM ammonium bicarbonate buffer

(pH 7.0) at 10 mg/ml and 20 mg/ml, respectively, frozen at

-70°C, and dried under vacuum. The powder thus obtained vas completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 40: Preparation of human growth hormone-containing dextran sulfate microparticles by freeze drying

Human growth hormone and dextran sulfate (MW: 25,000) were dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 10 mg/ml and 50 mg/ml, respectively, frozen at -70°C, and • dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen- Bradley, USA) .

EXAMPLE 41: Preparation of human growth hormone-containing dextran sulfate, polyethylene glycol microparticles by freeze drying

Human growth hormone, dextran sulfate (MW: 25,000) and polyethylene glycol (MW: 3,350) were dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 10 mg/ml, 10 mg/ml and 20 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 42: Preparation of interferon alpha-containing dextran microparticles by spray drying

Interferon alpha, human serum albumin and dextran (MW: 70,000) were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml, 4 mg/ml and 20 mg/ml, respectively, and supplied to a spray dryer (Buchi- 191) at a flow rate of 2.5 ml/min, thereby yielding interferon alpha-containing dextran microparticles. Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 43: Preparation of interferon alpha-containing polyethylene glycol microparticles by spray drying Interferon alpha and polyethylene glycol (MW: 10,000) were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 9 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing polyethylene glycol microparticles . Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 44: Preparation of interferon alpha-containing polyethylene glycol microparticles by spray drying Interferon alpha, human serum albumin and polyethylene glycol (MW: 10,000) were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml, 4 mg/ml and 10 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing polyethylene glycol microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 2 urn in average diameter.

EXAMPLE 45: Preparation of interferon alpha-containing carboxymethylcellulose microparticles by spray drying

Interferon alpha and carboxymethylcellulose were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 9 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing carboxymethylcellulose microparticles. Herein, drying air at 98°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 46: Preparation of interferon alpha-containing methylcellulose microparticles by spray drying

Interferon alpha and methylcellulose were individually dissolved in 10 mM ammonium bicarbonate buffer

(pH 7.0) at 1 mg/ml and 3 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing methylcellulose microparticles. Herein, drying air at 90°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 47: Preparation of interferon alpha-containing dextran sulfate microparticles by spray drying

Interferon alpha, human serum albumin and dextran sulfate (MW: 25,000) were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 1 mg/ml, 9 mg/ml and 50 mg/ml, respectively, and supplied to a spray dryer (Buchi- 191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing polyethylene glycol microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 48: Preparation of interferon alpha-containing chondroitin sulfate microparticles by spray drying

Interferon alpha and chondroitin sulfate were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 1 mg/ml and 20 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing chondroitin sulfate microparticles. Herein, drying air at 92°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 49: Preparation of interferon alpha-containing dermatan sulfate microparticles by spray drying

Interferon alpha and dermatan sulfate were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 1 mg/ml and 20 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 2.5 ml/min, thereby yielding interferon alpha-containing dermatan sulfate microparticles . Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter.

EXAMPLE 50: Preparation of interferon alpha-containing keratan sulfate microparticles by spray drying

Interferon alpha and keratan sulfate were individually dissolved in 10 mM ammonium acetate buffer (pH 4.0) at 1 mg/ml and 20 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing keratan sulfate microparticles. Herein, drying air at 95°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 51 : Preparation of interferon alpha-containing heparan sulfate microparticles by spray drying

Interferon alpha and heparan sulfate were individually dissolved in 10 mM ammonium acetate buffer (pH

4.0) at 1 mg/ml and 20 mg/ml, respectively, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing heparan sulfate microparticles. Herein, drying air at 85°C was introduced into the spray dryer, and the obtained microparticles were 2 μm in average diameter.

EXAMPLE 52 : Preparation of erythropoietin-containing polyethylene glycol microparticles by spray drying

The erythropoietin (EPO) microparticles prepared in Example 14 were homogeneously dispersed at 5 mg/ml in a solution prepared by dissolving polyethyleneglycol (MW: 3,350) in methylene chloride at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding EPO-containing polyethylene glycol microparticles . Herein, drying air at 55°C was introduced into the spray dryer, and the obtained microparticles were 3 μm in average diameter. EXAMPLE 53 : Preparation of G-CSF-containing polyethylene glycol microparticles by spray drying

The granulocyte colony stimulating factor (G-CSF) microparticles prepared in Example 15 were homogeneously dispersed at 5 mg/ml in a solution prepared by dissolving polyethyleneglycol (MW: 3,350) in methylene chloride at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding G-CSF-containing polyethylene glycol microparticles. Herein, drying air at 55°C was introduced into the spray dryer, and the obtained microparticles were 5 μm in average diameter.

EXAMPLE 54 : Preparation of interferon alpha-containing dextran microparticles by freeze drying

Interferon alpha, mannitol and dextran (MW: 70,000) were dissolved in 10 mM ammonium bicarbonate buffer (pH

7.0) at 1 mg/ml, 9 mg/ml and 90 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 55: Preparation of interferon alpha-containing polyethylene glycol microparticles by freeze drying

Interferon alpha, zinc chloride and polyethylene glycol (MW: 10,000) were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml, 0.06 mg/ml and 10 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 56: Preparation of interferon alpha-containing polyethylene glycol microparticles by freeze drying

Interferon alpha and polyethylene glycol (MW: 3,350) were dissolved in 10 mM ammonium bicarbonate buffer (pH

7.0) at 1 mg/ml and 10 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 57 : Preparation of interferon alpha-containing carboxymethylcellulose microparticles by freeze drying Interferon alpha and carboxymethylcellulose were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 20 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained .was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen- Bradley, USA) .

EXAMPLE 58: Preparation of interferon alpha-containing methylcellulose microparticles by freeze drying

Interferon alpha and methylcellulose were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 5 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 59: Preparation of interferon alpha-containing dextran sulfate microparticles by freeze drying

Interferon alpha and dextran sulfate (MW: 25,000) were dissolved in 10 mM ammonium acetate buffer (pH 4.0) at

1 mg/ml and 9 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen- Bradley, USA) . EXAMPLE 60 : Preparation of interferon alpha-containing chondroitin sulfate microparticles by freeze drying

Interferon alpha and chondroitin sulfate were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 5 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen- Bradley, USA) .

EXAMPLE 61: Preparation of interferon alpha-containing dermatan sulfate microparticles by freeze drying

Interferon alpha and dermatan sulfate were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 5 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 62 : Preparation of interferon alpha-containing heparan sulfate microparticles by freeze drying Interferon alpha and heparan sulfate were dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 1 mg/ml and 10 mg/ml, respectively, frozen at -70°C, and dried under vacuum. The powder thus obtained was completely ground in a crystal mortar, and particles less than 50 μm in diameter were separated using a sonic sifter (Allen-Bradley, USA) .

EXAMPLE 63: Preparation of interferon alpha microparticles by bubble drying

Interferon alpha, polyethylene glycol and human serum albumin were individually dissolved in 10 mM ammonium bicarbonate buffer (pH 7.0) at 3.3 mg/ml, 13.3 mg/ml and

33.4 mg/ml, respectively, and supplied to a bubble dryer (BD-500) at a flow rate of 0.3 ml/min, thereby yielding interferon alpha microparticles. Herein, drying air at 60°C was introduced into the bubble dryer, and the obtained microparticles were 1.5 μm in average diameter.

Methods of preparing sustained release formulations containing protein particles are provided in an illustrative manner in Examples 64 to 89.

EXAMPLE 64 : Preparation of a sustained release disc formulation containing human serum albumin coated with a hydrophilic polymer Trilaurin was completely mixed with the human serum albumin-containing polyethylene glycol (MW: 10,000) particles prepared in Example 18 at a ratio of 90:10. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding a human serum albumin-containing disc.

EXAMPLE 65: Preparation of a sustained release rod formulation containing human serum albumin coated with a hydrophilic polymer

Trilaurin was completely mixed with the human serum albumin-containing polyethylene glycol (MW: 3,350) particles prepared in Example 19 at a ratio of 90:10. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding a human serum albumin-containing rod.

EXAMPLE 66: Preparation of a sustained release rod formulation containing interferon alpha coated with a hydrophilic polymer Trilaurin, human serum albumin, and the interferon alpha-containing polyethylene glycol (MW: 10,000) particles prepared in Example 43 were completely mixed at a ratio of 95:2:3. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod.

EXAMPLE 67 : Preparation of a sustained release rod formulation containing interferon alpha coated with a hydrophilic polymer

Trilaurin, human serum albumin, and the interferon alpha-containing polyethylene glycol (MW: 10,000) particles prepared in Example 43 were completely mixed at a ratio of 90:4:6. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod.

EXAMPLE 68 : Preparation of a sustained release rod formulation containing interferon alpha coated with a hydrophilic polymer

Trilaurin and the interferon alpha-containing microparticles prepared in Example 44 were completely mixed at a ratio of 90:10. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha- containing rod.

EXAMPLE 69: Preparation of a sustained release disc formulation containing human serum albumin

Lauric acid was completely mixed with the human serum albumin-containing polyethylene glycol particles prepared in Example 18 at a ratio of 7:3. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding a human serum albumin-containing disc.

EXAMPLE 70: Preparation of a sustained release rod formulation containing human serum albumin

Palmitic acid was completely mixed with the human serum albumin-containing polyethylene glycol particles prepared in Example 20 at a ratio of 7:3. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding a human serum albumin-containing rod.

EXAMPLE 71: Preparation of a sustained release rod formulation containing human serum albumin Glyceryl monostearate was completely mixed with the human serum albumin-containing methylcellulose particles prepared in Example 21 at a ratio of 70:30. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding a human serum albumin-containing rod.

EXAMPLE 72 : Preparation of a sustained release disc formulation containing human growth hormone

Lauric acid was completely mixed with the human growth hormone-containing polyethylene glycol particles prepared in Example 38 at a ratio of 7:3. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding a human growth hormone-containing disc.

EXAMPLE 73: Preparation of a sustained release rod formulation containing human growth hormone

Palmitic acid was completely mixed with the human growth hormone-containing dextran sulfate particles prepared in Example 40 at a ratio of 7:3. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding a human growth hormone-containing rod.

EXAMPLE 74: Preparation of a sustained release rod formulation containing human growth hormone

The human growth hormone microparticles prepared in Example 6 were homogeneously dispersed at 5 mg/ml in a solution prepared by dissolving polyethyleneglycol (MW: 3,350) in methylene chloride at 10 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding human growth hormone-containing polyethylene glycol microparticles. Then, trilaurin was completely mixed with the microparticles at a ratio of 8:2. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding a human growth hormone-containing rod.

EXAMPLE 75: Preparation of a sustained release disc formulation containing human growth hormone

Glyceryl myristrate was completely mixed with the human growth hormone-containing dextran sulfate particles prepared in Example 40 at a ratio of 8:2. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding a human growth hormone-containing disc.

EXAMPLE 76: Preparation of a sustained release rod formulation containing human growth hormone

Trilaurin was completely mixed with the human growth hormone-containing dextran sulfate particles prepared in Example 41 at a ratio of 6:4. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding a human growth hormone-containing rod.

EXAMPLE 77: Preparation of a sustained release rod formulation containing interferon alpha

The interferon alpha microparticles prepared in Example 8 were homogeneously dispersed at 5 mg/ml in a solution prepared by dissolving polyethyleneglycol (MW.: 3,350) in methylene chloride at 5 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing polyethylene glycol microparticles . Then, trilaurin was completely mixed with the microparticles at a ratio of 8:2. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod. EXAMPLE 78: Preparation of a sustained release rod formulation containing interferon alpha

Glyceryl monostearate was completely mixed with the interferon alpha-containing dextran microparticles prepared in Example 42 at a ratio of 70:30. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod.

EXAMPLE 79: Preparation of a sustained release disc formulation containing interferon alpha

Lauric acid was completely mixed with the interferon alpha-containing polyethylene glycol particles prepared in Example 43 at a ratio of 8:2. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding an interferon alpha-containing disc.

EXAMPLE 80: Preparation of a sustained release rod formulation containing interferon alpha Palmitic acid was completely mixed with the interferon alpha-containing methylcellulose particles prepared in Example 46 at a ratio of 70:30. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod.

EXAMPLE 81: Preparation of a sustained release disc formulation containing interferon alpha

Glyceryl myristrate was completely mixed with the interferon alpha-containing chondroitin sulfate particles prepared in Example 48 at a ratio of 8:2. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding an interferon alpha-containing disc.

EXAMPLE 82: Preparation of a sustained release rod formulation containing interferon alpha

Trilaurin was completely mixed with the interferon alpha-containing keratan sulfate microparticles prepared in

Example 51 at a ratio of 6:4. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod. EXAMPLE 83: Preparation of a sustained release disc formulation containing interferon alpha

The interferon alpha particles prepared in Example 54 were homogeneously dispersed at 5 mg/ml in a solution prepared by dissolving polyethyleneglycol (MW: 3,350) in methylene chloride at 5 mg/ml, and supplied to a spray dryer (Buchi-191) at a flow rate of 3.0 ml/min, thereby yielding interferon alpha-containing polyethylene glycol microparticles. Then, trilaurin was completely mixed with the microparticles at a ratio of 8:2. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing disc.

EXAMPLE 84: Preparation of a sustained release rod formulation containing interferon' alpha

Palmitic acid was completely mixed with the interferon alpha-containing polyethylene glycol particles prepared in Example 55 at a ratio of 70:30. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod. EXAMPLE 85: Preparation of a sustained release disc formulation containing interferon alpha

Glyceryl myristrate was completely mixed with the interferon alpha-containing dextran sulfate particles prepared in Example 59 at a ratio of 8:2. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding an interferon alpha-containing disc.

EXAMPLE 86: Preparation of a sustained release rod formulation containing interferon alpha

Trilaurin was completely mixed with the interferon alpha-containing chondroitin sulfate microparticles prepared in Example 60 at a ratio of 6:4. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod.

EXAMPLE 87: Preparation of a sustained release rod formulation containing erythropoietin Trilaurin was completely mixed with the erythropoietin-containing polyethylene glycol microparticles prepared in Example 52 at a ratio of 9:1. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an EPO-containing rod.

EXAMPLE 88: Preparation of a sustained release rod formulation containing G-CSF

Trilaurin was completely mixed with the G-CSF- containing microparticles prepared in Example 53 at a ratio of 9:1. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding a G-CSF-containing rod.

EXAMPLE 89: Preparation of a sustained release rod formulation containing interferon alpha

Trilaurin was completely mixed with the interferon alpha-containing microparticles prepared in Example 63 at a ratio of 85:15. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.8 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha- containing rod.

COMPARATIVE EXAMPLE 1: Preparation of a human serum albumin-containing disc formulation Trilaurin was completely mixed with the human serum albumin particles prepared in Example 1 at a ratio of

90:10. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding a human serum albumin-containing disc.

COMPARATIVE EXAMPLE 2: Preparation of a human serum albumin-containing rod formulation

Trilaurin was completely mixed with the human serum albumin particles prepared in Example 1 at a ratio of

90:10. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding a human serum albumin-containing rod.

COMPARATIVE EXAMPLE 3: Preparation of an interferon alpha- containing rod formulation

Trilaurin was completely mixed with the interferon alpha particles prepared in Example 10 at a ratio of 84:11. 200 mg of the mixture were extruded to a thickness of 1 mm under pressure of 0.4 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha-containing rod. COMPARATIVE EXAMPLE 4 : Preparation of an interferon alpha- containing disc formulation

Trilaurin was completely mixed with the interferon alpha particles prepared in Example 10 at a ratio of 91:8. 200 mg of the mixture were placed in a 13mm KBr die (Pike, USA) and compressed under pressure of 0.4 ton for 1 min using a carver laboratory press, thereby yielding an interferon alpha-containing disc.

COMPARATIVE EXAMPLE 5: Preparation of an interferon alpha- containing rod formulation by melting and cooling

Pre-melted myristic acid was rapidly and completely mixed with the interferon alpha microparticles prepared in Example 10 at a ratio of 19:1. The mixture was injected into a silicon tube 0.8 mm in inner diameter and cooled. The sufficiently cooled rod was recovered from the tube, thereby yielding an interferon alpha-containing myristic acid rod.

COMPARATIVE EXAMPLE 6: Preparation of an interferon alpha- containing rod formulation by melting and cooling Pre-melted lauric acid was rapidly and completely mixed with the interferon alpha microparticles prepared in Example 10 at a ratio of 19:1. The mixture was injected into a silicon tube 0.8 mm in inner diameter and cooled. The sufficiently cooled rod was recovered from the tube, thereby yielding an interferon alpha-containing lauric acid rod.

COMPARATIVE EXAMPLE 7: Preparation of an interferon alpha- containing microsphere formulation by melting and dispersion Pre-melted diglyceryl palmitostearate was completely mixed with the interferon alpha microparticles prepared in Example 10 at a ratio of 19:1. The mixture was dispersed in a 0.25% polyvinylalcohol solution at 55°C and cooled, thereby yielding interferon alpha-containing microspheres .

COMPARATIVE EXAMPLE 8: Preparation of an interferon alpha- containing rod formulation by melting and cooling

A solution prepared by completely mixing and melting caproic acid and lauric acid at a ratio of 1:9 was mixed with human serum albumin and the interferon alpha- containing polyethylene glycol microparticles prepared in Example 43 at a ratio of 85:13:2. The resulting mixture was injected into a silicon tube 0.8 mm in inner diameter and cooled. The sufficiently cooled rod was recovered from the tube, thereby yielding an interferon alpha-containing rod.

COMPARATIVE EXAMPLE 9: Preparation of an interferon alpha- containing rod formulation by simple mixing with polyethylene glycol

2 mg of interferon alpha, 8 mg of polyethylene glycol, 20 mg of human serum albumin and 170 mg of trilaurin were completely mixed and finely ground in a crystal mortar. The resulting mixture was extruded to a thickness of 1 mm under pressure of 0.8 ton at 37°C using a ram-type extruder, thereby yielding an interferon alpha- containing rod.

The following Test Examples revealed that the sustained release formulations of the present invention stabilize protein drugs, suppress the high initial release of the protein drugs, and sustain the release of the protein drugs for a longer period of time. An in vitro release test was performed using 10 mM PBS (pH 7.0), and drug release was quantitatively analyzed using analysis conditions described in EUROPEAN PHARMACOPOEIA. In the case of interferon, a low content of interferon was detected using a fluorescence detector with excitation (Ex) at 280 nm and emission (Em) at 350 nm. An in vivo release test was performed using 6-7 week old SD male rats weighing 200-250 g. An interferon alpha- containing formulation was subcutaneously injected into the rats, and serum levels of interferon alpha were measured using an ELISA kit.

TEST EXAMPLE 1: Protein stability test

The protein stability in a sustained release preparation after manufacture of the formulation and during drug release was assessed. Interferon alpha was extracted from the interferon alpha-containing sustained release rod prepared in Example 66. Also, 3 days after an in vitro release test, interferon alpha remaining in the formulation was extracted. The protein stability was analyzed by reverse phase HPLC, and the results are given in FIG. 1. FIG. la is a chromatogram of interferon alpha extracted from the sustained release formulation immediately after the formulation was manufactured. FIG. lb is a chromatogram of interferon alpha extracted from the sustained release formulation during the in vitro release test. The protein was found not to be denatured during the preparation of the interferon alpha-containing sustained release formulation and the in vitro release test. In contrast, when the rod formulations, prepared from a mixture of interferon alpha with a melted lipid • in Comparative Examples 5 and 6, were tested for in vitro drug release, and the released interferon alpha in the supernatants was analyzed by size exclusion chromatography, protein denaturation due to heat was observed. Also, compared to the interferon alpha-containing rod prepared in Example 89, in which the protein was coated with a hydrophilic polymer, the interferon alpha-containing rod prepared by simple mixing with a hydrophilic polymer in Comparative Example 9 did not stabilize the protein, leading to protein denaturation during the in vitro release test. The results are given in FIGS. 3a, 3b, 3c, 3d and 3e.

TEST EXAMPLE 2: Initial in vitro release test

The preparations prepared in Examples 64 to 67 and Comparative Examples 1 to 8 were cut into a suitable size, added to 10 mM phosphate buffer at the same protein concentration, and incubated at 37°C for 1 hr. The released proteins in the supernatants were quantified by liquid chromatography. The results are given in Tables 1 and 2, below. TABLE 1 Initial in vitro release of human serum albumin-containing formulations

As shown in Table 1, the initial in vitro release of human serum albumin from the formulations was reduced by protecting protein particles by a hydrophilic polymer regardless of the dosage forms of the formulations . The same results were found in the data of Table 2.

TABLE 2 Initial in vitro release of interferon alpha-containing formulations

As shown in Table 2, the formulations of Examples 66 and 67, in which interferon alpha particles were protected by coating with a hydrophilic polymer, had a reduced initial release of the protein compared to the formulations of Comparative Examples 3, 5, 6 and 7 comprising interferon alpha not coated with a hydrophilic polymer. Also, the formulation of Comparative Example 8, which was prepared by mixing protein particles, coated with a hydrophilic polymer, with a melted lipid substance, displayed a reduction in the initial release of interferon alpha. However, as revealed in the following in vivo release test, the formulation of Comparative Example 8 did not sustain protein release for more than 24 hrs because it was highly porous due to the lipid matrix to which pressure was not applied. On the other hand, the formulation of Example 67, which has a two fold higher protein content than the formulation of Example 66, was found to have a further reduced initial in vitro release rate of interferon alpha by doubling the amount of the hydrophilic polymer. In contrast, when the protein particles (Example 43) coated with a hydrophilic polymer, used in Example 67, were suspended in a buffer, all protein particles were dissolved in the buffer within 1 to 2 min. These results indicate that the coating of a protein with a hydrophilic polymer increases the stability of the protein and reduces the initial release of the protein by separating the protein from a lipid matrix. In addition, the following in vitro release tests confirmed that protein particles coated with a hydrophilic polymer are stable and a lipid forming a dense matrix under pressure realizes sustained release of a protein drug. TEST EXAMPLE 3: In vivo release test in white rats

The formulation of Example 89 was subcutaneously injected into SD rats at a dose of interferon alpha of 100 μg/kg. The formulations of Comparative Examples 4, 5, 6 and 8 were subcutaneously injected into SD rats at doses of interferon alpha of 25 μg/kg, 19 μg/kg, 18 μg/kg and 30 μg/kg, respectively. Serum levels of interferon alpha were measured using an ELISA kit before administration and at given time points after administration. The results are given in FIGS. 2a, 2b and 2c. When the formulation of Comparative Example 4 was administered to rats, serum interferon sharply decreased to undetectable levels after 24 hrs. The formulation of Example 89 sustained the release of interferon alpha for a period of more than 3 days. This is because the lipid matrix of the formulation of Comparative Example 4 was densely formed under pressure but protein particles were not protected by a hydrophilic polymer and were thus denatured in the lipid matrix and not released during the test. Also, as shown in FIG. 2c, all of the formulations of Comparative Examples 5, 6 and 8 had a slightly high initial release rate even though the dose of interferon alpha was much lower than the formulation of Example 89, and did not sustain the release of interferon alpha for a period of more than 24 hrs. This is because protein particles, not protected by a hydrophilic polymer, were denatured by the lipid matrix, heat, or the like and were not released. Also, this resulted from the fact that, although protein particles were protected by a hydrophilic polymer, a pharmaceutical preparation prepared by melting and cooling has a high initial release rate and does not have a sustained release capability because the melting and cooling method cannot form a dense lipid matrix.

TEST EXAMPLE 4 : In vivo release test in monkeys

The formulation of Example 89 was subcutaneously injected into monkeys at doses of interferon alpha of 100 μg/kg and 250 μg/kg. Serum levels of interferon alpha were measured using an ELISA kit before administration and at given time points after administration. The results are given in FIG. 2d. When monkeys were treated with interferon alpha at 100 and 250 μg/kg, they showed 2.5 fold increased _røx values that were 10060 pg/ml and 28657 pg/ml, respectively, and 2.6 fold increased AUC values that were 19260 pg-day/ml and 50307 pg-day/ml, respectively. The C_maX and AUC values were increased with the dose. When the results in this test for the formulation of Example 89 were compared with those of Test Example 3, the release of interferon alpha was sustained for a longer period of more than 9 days in monkeys. This is believed to result from a difference between species. The above Test Examples demonstrates that the sustained release formulation of the present invention does not cause protein denaturation after manufacture and has therapeutic efficacy for a longer period of time without high initial release of a protein drug. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims .

Industrial Applicability

As described hereinbefore, the lipid implant preparation of the present invention solves the problem of instability of protein drugs, encountered in conventional sustained release preparations using a hydrophobic matrix such as lipids, by stabilizing a protein drug as an active ingredient with a hydrophilic polymer, homogeneously mixing the protein drug with a lipid substance, and compressing the mixture. The lipid implant preparation sustains the in vivo release of a protein drug in an active form and at an effective concentration for a longer period of time. Therefore, the protein-containing lipid implant for sustained delivery according to the present invention can effectively treat diseases and reduce injection frequency.

Claims

1. A protein-containing lipid implant for sustained delivery, comprising a compressed mixture of a protein drug coated with a hydrophilic polymer and a lipid, wherein the hydrophilic polymer has a molecular weight of more than 2,000 daltons and is selected from polyethylene glycol, polyvinylpyrrolidone, polyvinylalcohol, polyethyleneimine, dextran, dextran sulfate, chondroitin sulfate, dermatan sulfate, heparan sulfate, keratan sulfate, hyaluronic acid, chitosan, albumin, collagen, fibrin and mixtures thereof; and the lipid is solid at room temperature and is selected from fatty acids, monoglycerides, diglycerides, triglycerides, sorbitan fatty acid esters, phospholipids, sphingolipids, cholesterol, waxes, and salts and derivatives thereof.

2. The protein-containing lipid implant for sustained delivery according to claim 1, wherein the protein drug comprises an additional protein stabilizer.

3. The protein-containing lipid implant for sustained delivery according to claim 2, wherein the additional protein stabilizer is selected from sugars, polyols, surfactants, amino acids, inorganic salts and mixtures thereof.

4. The protein-containing lipid implant for sustained delivery according to claim 1, wherein the content of the hydrophilic polymer in the protein drug coated with the hydrophilic polymer ranges from 0.1 to 99.9 wt% .

5. The protein-containing lipid implant for sustained delivery according to claim 1, wherein the content of the lipid in the protein-containing lipid implant for sustained delivery ranges from 40 to 99 wt%.

6. The protein-containing lipid implant for sustained delivery according to claim 1, which is in a disc, pellet or rod form.

7. A method of preparing a protein-containing lipid implant for sustained delivery, comprising: coating a protein drug with a hydrophilic polymer, which has a molecular weight of more than 2,000 daltons and is selected from polyethylene glycol, polyvinylpyrrolidone, polyvinylalcohol, polyethyleneimine, dextran, dextran sulfate, chondroitin sulfate, dermatan sulfate, heparan sulfate, keratan sulfate, hyaluronic acid, chitosan, albumin, collagen, fibrin and mixtures thereof, to yield a solid protein powder; mixing the coated solid protein powder with a lipid, which is solid at room temperature and is selected from fatty acids, monoglycerides, diglycerides, triglycerides, sorbitan fatty acid esters, phospholipids, sphingolipids, cholesterol, waxes, and salts and derivatives thereof; and compressing or extruding the mixture to be formulated into a pharmaceutical dosage form.

8. The method according to claim 7, wherein the solid protein powder coated with the hydrophilic polymer is 0.1 μm to 200 μm in diameter.

9. The method according to claim 7, wherein the solid protein powder coated with the hydrophilic polymer is prepared by dispersing protein microparticles in a solution in which the hydrophilic polymer is dissolved and drying a resulting dispersion by a method selected from spray drying, freeze drying, spray freeze drying and bubble drying .

10. The method according to claim 9, wherein the protein microparticles are prepared by drying an aqueous solution in which a protein is dissolved using a method selected from spray drying, freeze drying, spray freeze drying and bubble drying.

11. The method according to claim 7, wherein the solid protein powder coated with the hydrophilic polymer is prepared by dissolving protein molecules and the hydrophilic polymer and drying a resulting solution by a method selected from spray drying, freeze drying, spray freeze drying and bubble drying.

12. The method according to any one of claims 9 to 11, further comprising adding an additional protein stabilizer.

13. The method according to claim 12, wherein the additional protein stabilizer is selected from sugars, polyols, surfactants, amino acids, inorganic salts and mixtures thereof.

14. The method according to claim 13, wherein the sugar is selected from sucrose, glucose, inositol, trehalose, maltose, mannitol, lactose, mannose, xylitol, sorbitol and cyclodextrin.