WO2009091103A1

WO2009091103A1 - Complex of biopolymers and insoluble biomolecules, and manufacturing method thereof

Info

Publication number: WO2009091103A1
Application number: PCT/KR2008/003248
Authority: WO
Inventors: Tae-Gwan Park; Hyuk-Jin Lee; Kyu-Ri Lee
Original assignee: Korea Advanced Institute Of Science And Technology
Priority date: 2008-01-14
Filing date: 2008-06-11
Publication date: 2009-07-23
Also published as: KR20090078098A; KR100957125B1

Abstract

Disclosed are a method for preparing a complex of biopolymers and insoluble biomolecules by preventing hydrogen bonds between hydrophilic polymers, dissolving the hydrophilic polymers in a variety of organic solvents and combining the solubilized hydrophilic polymers with different insoluble biomolecules to produce a conjugate, as well as the complex of biopolymers and insoluble biomolecules produced by the above method. The complex of biopolymers and insoluble biomolecules prepared according to the present invention forms nanosized micelles through self-assembly in an aqueous solution and such formed micelles can be effectively used in manufacturing cell specific treatment products.

Description

COMPLEX OF BIOPOLYMERS AND INSOLUBLE BIOMOLECULES, AND MANUFACTURING METHOD

THEREOF

Technical Field

[1] The present invention relates to complexes (often called "conjugates") of biopolymers and insoluble biomolecules, and methods for manufacturing the same and, more particularly, to a method for preparation of a complex (hereinafter, referred to as "conjugate") of biopolymers and insoluble biomolecules by preventing hydrogen bonds between hydrophilic polymers, dissolving the hydrophilic polymers in a variety of organic solvents and combining the solubilized hydrophilic polymers with different insoluble biomolecules to produce a conjugate, as well as the complex of biopolymers and insoluble biomolecules produced by the above method. Background Art

[2] Paclitaxel is a strong anti-cancer drug originally extracted from bark of Taxus brevifolia, and is broadly known to have anti-cellular division activity that promotes conversion of tubulin composites into stable microtubules.

[3] Paclitaxel prevents depolymerization of polymerized microtubules so as to inhibit cellular replication oxurring at delayed G2/M phase of a cellular circulation cycle. Paclitaxel shows potentially excellent ability as an anti-cancer drug but has limited water- solubility which restricts general use thereof, especially in cancer treatment applications.

[4] In recent years, many researches and studies have reported that a cremophor EL involves various adverse effects such as sensitivity, neurotoxicity, nerve disorders, etc. although clinical formulations with improved water solubility such as Taxol

® as a mixture of paclitaxel in the cremophor EL and ethanol in a ratio of 50:50 having improved water solubility, are used in systemic administration (see Onetto, N.; Grechko J., Overview of Taxol safety, J. Natl. Cancer Inst. Monogr. 1993, 15, 131. ; Mazzo, D.; Denis, P., Compatibility of docetaxel and paclitaxel in intravenous solutions with polyvinyl chloride infusion materials, Am. J. Health Sys. Pharm. 1997, 54, 566. ; Gregory R.; Delisa, A.F., Paclitaxel: a new antineoplastic agent for refractory ovarian cancer, Clin. Pharm. 1993, 12, 401.). [5] Among conventional attempts to overcome significant adverse effects, there has been proposed a process for manufacturing paclitaxel formulations by encapsulating pa- clitaxel portion in specific carriers including, for example, polymeric complexes, liposomes, polymeric micelles, emulsions and/or nanospheres (see Crosasso P.; Cartel, L., Preparation, characterization and properties of sterically stabilized paclitaxel- containing liposomes, J. Controlled Release 2000, 63, 19. ; Bae, K.H.; Lee, Y.; Park, T.G., Oil-encapsulating PEO-PPO-PEO Shell Crosslinked Nanocapsules for Target- specific Delivery of Paclitaxel, Biomacromolecules 2007, 8, 650. ; Tarr, BD.; Sambandan, T.G.; Yalkowsky, S. H., A new parenteral emulsion for the administration of Taxol, Pharm. Res. 1987, 4, 162. ; Ebrdunoo, S. K.; Burt, H.M., Taxol encapsulation in poly (ε-caprolactone) microspheres, Cancer Chemother. Pharmacol. 1995, 36, 279).

[6] Especially, drug-polymeric complexes have advantages apparently distinguished from general polymeric nano- sized carriers, such as high drug content, excellent water- solubility, extension of drug half-life in vivo, improved anti-cancer effect, etc.

[7] Although water-soluble synthetic polymers were traditionally used in drug combination, naturally generated polymers with inherent cell-specific bonding abilities also have superior performances suitable for target- specific drug carriers. For example, hyaluronic acid (HA) is one of naturally formed polysaccharides, which consists of N- acetyl-D-glucosamine and D -glucuronic acid and has stronger affinity to particular cell-specific surface markers such as CD44 and RHAMM.

[8] HA plays an important role in biological functions including, for example: stabilization and construction of BCM; control of cell adhesion and self-motility; control of cell proliferation and division, and the like. HA also closely correlates to angiogenesis for various tumors and, in this case, HA receptors (CD44 and RHAMM) are excessively expressed from surface of the tumor. Therefore, malignant cells with high metastasis activity often exhibit improved HA bonding and absorption abilities. Accordingly, HA and its derivatives have been widely used as aimed specific drug delivery media for different medical treatment products.

[9] Chemical modification and combination of HA have been performed in water solutions through reactive functional radicals of HA such as carboxyl group, hydroxyl group and reducing terminals (see Luo, Y.; Prestwich, GD., Hyaluronic acid- N-hydroxysuαinimide: A useful intermediate for bioconjugation, Bioconjugate Chem. 2001, 12, 1085. ; Zhang, M., James, S. P., Synthesis and properties of melt-processable hyaluronan esters, J. Mat. Sd. 2005, 40, 2937. ; Ruhela, D.; Szoka, F.C., Efficient synthesis of an aldehyde functionalized hyaluronic acid and its application in the preparation of hyaluronan-lipid conjugates, Bioconjugate Chem. 2006, 17, 1360.).

[10] However, extreme insolubility of HA in organic solvents restricts the combination of

HA being applied to hydrophobic polymers, drugs and/or lipids.

[11] In order to overcome the above problems, a variety of solubilization methods were applied in production of homogeneous mixtures of HA and hydrophobic reactants dissolved in typical solvents. For example, a mixture of an organic solvent and water (i.e., DMSO/H₂O or DMF/H₂0) was used to co-dissolve HA and paclitaxel (see Luo, Y.; Prestwich, GD., Synthesis and selective cytotoxicity of a hyaluronic acid- antitumor bioconjugate, Bioconjugate chem. 1999, 10, 755.).

[12] For improvement of HA solubilities in polar organic solvents required in subsequent modification processes, HA/ammonium complex salts were formed by precipitating multi-anionic HA with aliphatic quaternary ammonium compounds (see Zhang, M.; James, S. P., Silylation of hyaluronan to improve hydrophobidty and reactivity for improved processing and derivatization, Polymer 2005, 46, 3639.).

[13] However, the above known methods had disadvantages in that these demanded all of amine and carboxyl groups for combination of HA in a combined water/organic solvent phase and used ammonium surfactants with environmental cytotoxicity not suitable to delivery of drugs and/or biological or medical products.

[14] As described above, since most of hydrophilic biopolymers have stronger hydrogen bonds and a defect of less solubility in organic solvents except water, there is a strong requirement for development of novel methods for combination of solubilized hydrophilic polymers and a number of insoluble materials such as insoluble drugs, fatty acids and synthetic polymers by preventing hydrogen bonds between the biopolymers so as to dissolve the hydrophilic polymers in various organic solvents. Disclosure of Invention Technical Problem

[15] Accordingly, the present invention is directed to solve the problems described above in regard to conventional methods and an object of the present invention is to provide a novel method for preparing a complex of biopolymers and insoluble biomolecules by preventing hydrogen bonds between hydrophilic polymers, dissolving the hydrophilic polymers in a variety of organic solvents, and combining the solubilized hydrophilic polymers with different kinds of insoluble biomolecules.

[16] Another object of the present invention is to provide a complex of biopolymers and insoluble molecules prepared by the above method. Technical Solution

[17] In order to accomplish the above objects, the present invention provides a method for preparing a complex of biopolymers and insoluble biomolecules, comprising the steps of: (a) admixing a hydrophilic biopolymer with biodegradable poly (ethylene glycol) polymer in an aqueous solution after removing salts of the hydrophilic biopolymer to prepare a conjugate of the hydrophilic biopolymer and the biodegradable poly (ethylene glycol), lyophilizing the conjugate and dissolving the lyophilized conjugate of the hydrophilic biopolymer and the biodegradable poly (ethylene glycol) in an organic solvent to prepare nano-conjugate; (b) reacting the solubilized nano-conjugate solution of the biopolymer and the biodegradable poly (ethylene glycol) in the presence of a coupling agent to activate the biopolymer; and (c) adding insoluble biomolecules, which were dissolved in an alternative organic solvent, to the conjugate solution with activated polymer to derive a reaction between them.

[18] The present invention further provides a complex of biopolymers and insoluble biomolecules produced by the above method.

Advantageous Effects

[19] The complex of biopolymers and insoluble biomolecules prepared according to the present invention forms nanosized micelles through self-assembly in an aqueous solution. The insoluble biomolecules released from the micelles show pH-dependent degradable properties and may exhibit stronger cytotoxicity to biopolymer receptor over-expressed cancer cells rather than to biopolymer receptor deficient cells, so that the nanosized micelles formed by the complex can be effectively used as cell specific treatment products. Brief Description of the Drawings

[20] The above objects, features and advantages of the present invention will become more apparent to those skilled in the related art in conjunction with the accompanying drawings. In the drawings:

[21] Fig. 1 is a graph illustrating transmittance of DMSO solubilized in HA/dmPEG after blending the same at 8O⁰C for 2 hours, as a function of amount of dmPEG in the solution;

[22] Fig. 2 shows a combining reaction of each of HA-paclitaxel complexes prepared in

Examples 1 to 8 of the present invention;

[23] Fig. 3 shows ¹H-NMR spectra of HA-paclitaxel complexes dissolved in (A) D ₂O and

(B) DMSOd₆, respectively; [24] Fig. 4 shows (A) a result of measuring HA-paclitaxel nanoparticles by DLS; images of HA-paclitaxel nanoparticles obtained by (B) AFM (atomic force microscopy) and (Q TEM (transmission electron microscopy); and (D) a result of measuring CAC (critical aggregation concentration) by using pyrene, which represents an intensity ratio between I₃₃₉ and I₃₃₄ as a function of logarithmic concentration thereof;

[25] Fig. 5 is a graph illustrating results of HPLC measurement of paclitaxel released from HA-paclitaxel nanoparticles at different culturing pH values for 1 hour;

[26] Fig. 6 is graphs illustrating in vitro cytotoxicities of HA-paclitaxel and Taxol

® in three different cell lines including, (A) HCT-116, (B) MCF-7 and (Q NIH-373; [27] Fig. 7 is views illustrating co-focal images of PI (propidium iodide) stained HCT-116 cells treated by (A) a control, (B) Taxol

® and (Q HA-paclitaxel, respectively; and graphs illustrating results of FACS analysis for effect of cell apoptosis to HCT-116 cells caused by (D) the control, (E)Taxol

® and (F) HA-paclitaxel, respectively;

[28] Fig. 8 is (A) ¹H-NMR analysis spectrum of HA-PLGA and (B) FT-IR analysis spectrum of HA-PLGA illustrating results of analyzing structure of HA-PLGA prepared in Example 11 of the present invention;

[29] Fig. 9 is a graph illustrating CAC measurement result using pyrene, which represents an intensity ratio between I₃₃₉ and I₃₃₄ as a function of logarithmic concentration thereof;

[30] Fig. 10 shows images of HA-PLGA nanoparticles obtained by (A) AFM and (B)

TEM;

[31] Fig. 11 is graphs illustrating in vitro cytotoxicities of HA-PLGA nanoparticles containing doxorubicin and doxorubicin itself to HCT-116 cells;

[32] Fig. 12 shows co-focal images of HCT-116 cells treated for 2 hours by (A) doxorubicin and (B) HA-PLGA nanoparticles containing doxorubicin, respectively; and co-focal images of HCT-116 cells treated for 30 minutes by (Q doxorubicin and (D) HA-PLGA nanoparticles containing doxorubicin, respectively; and

[33] Fig. 13 is graphs illustrating results of FACS analysis for effects of HA-PLGA nanoparticles containing doxorubicin absorbed into HCT-116 cells when HA is contained in an aqueous solution (blue: HA-PLGA nanoparticles, red: doxorubicin). Best Mode for Carrying Out the Invention

[34] Although general processes for combination of insoluble biomolecules such as insoluble drugs have been conducted in organic solvents to date, methods for combination of hydrophilic biopolymers such as HA, DNA, RNA or polysaccharides with insoluble drugs have serious difficulty in selecting solvents suitable for dissolving both of the biopolymers and the insoluble drugs. More particularly, a variety of solvents are typically used in the combination process and, for example, DMSO and DMF are blended in a ratio of 1 : 1 and added to an aqueous solution for reaction thereof so as to prepare a combined solvent.

[35] However, for a reaction in the presence of water, it is impossible to perform biosynthesis and/or bioconjugation in different kinds of manners, therefore, it is required to produce a combination of hydrophilic biopolymers and insoluble biomolecules in an organic solvent after solubilizing the biopolymers in an alternative organic solvent.

[36] Most of hydrophilic biopolymers have strong hydrogen bonds and are rarely dissolved in organic solvents other than water.

[37] In the past, the present inventors reported a method for DNA solubilization in organic solvents with use of biocompatible poly (ethylene glycol) (PEG), which comprises formation of a nanosized complex salt (see Mok, H.; Park, T.G., PEG- assisted DNA solubilization in organic solvents for preparing cytosol specifically degradable PEG/DNA nanogels, Bioconjugate Chem. 2006, 17, 1369.).

[38] PEG has been commonly used in dissolution and stabilization of various macro- biomolecules in organic solvents. Because PEG can function as both of hydrogen bonding donor and receptor, the inventors presumed that addition of PEG to the organic solvent would accelerate formation of nano complex salt of HA/PEG by interaction and/or internal hydrogen bonds.

[39] Accordingly, using poly (ethylene glycol) (PEG) to prevent hydrogen bonds between biopolymers, hydrophilic biopolymers can be solubilized in a variety of organic solvents and, especially, the solubilized hydrophilic biopolymers can be combined with a number of insoluble drugs, fatty acids and/or synthetic polymers.

[40] Hereinafter, the present invention will be described in detail as follows.

[41] According to an aspect of the present invention, there is provided a method for preparing a complex of biopolymers and insoluble biomolecules, comprising the steps of: (a) admixing a hydrophilic biopolymer with biodegradable poly (ethylene glycol) polymer in an aqueous solution after removing salts of the hydrophilic biopolymer to prepare a conjugate of the hydrophilic biopolymer and the biodegradable poly (ethylene glycol), lyophilizing the conjugate and dissolving the lyophilized conjugate of the hydrophilic biopolymer and the biodegradable poly (ethylene glycol) in an organic solvent to prepare nano-conjugate; (b) reacting the solubilized nano-conjugate solution of the biopolymer and the biodegradable poly (ethylene glycol) in the presence of a coupling agent to activate the biopolymer; and (c) adding insoluble biomolecules, which were dissolved in an alternative organic solvent, to the conjugate solution with activated polymer to derive a reaction between them.

[42] According to the preparation method of the present invention, the hydrophilic biopolymers may include at least one selected from a group consisting of genes, hydrocarbon based polysaccharides such as hyaluronic add (HA) or heparin, protein and peptide.

[43] In the preparation method of the present invention, salts of hydrophilic biopolymers can be removed by dialysis or ethanol precipitation.

[44] According to the preparation method of the present invention, the biodegradable poly

(ethylene glycol) polymer may include at least one selected from a group consisting of: poly (ethylene glycol) having hydroxyl group; alkyl modified PEG substituted with alkyl group; amine modified PEG substituted with amine group; thiol modified PEG substituted with thiol group; carboxyl modified PEG substituted with carboxyl group; acryl modified PEG substituted with acryl group; linear PEG and branched PEG; and mixtures thereof. Preferably, an example of the alkyl modified PEG is dimethyl PEG.

[45] According to the present inventive method, genes may include at least one selected from a group consisting of DNA, plasmid genes, anti-sense oligonucleotides, siRNA and RNA, and mixtures thereof.

[46] HA among the hydrophilic biopolymers may include HA and derivatives thereof having all of molecular weights, while heparin may include heparins and derivatives thereof having different molecular weights.

[47] According to the present inventive method, the organic solvents to dissolve the hydrophilic biopolymers may include at least one selected from a group consisting of: methylene chloride; chloroform; acetone; dimethyl sulfoxide; dimethyl formamide; N- methyl pyrrolidone; dioxane; tetrahydrofuran; ethyl acetate; methylethyl ketone; ace- tonitrile; methanol; ethanol; and mixtures thereof.

[48] According to the present inventive method, a mixing ratio by weight of the hydrophilic biopolymer and the biodegradable poly (ethylene glycol) polymer in step (a) may range from 1:1 to 1:1,000 (w/w), preferably, from 1:1 to 1:10 (w/w) and, more preferably, 1:5 (w/w).

[49] According to the present inventive method, the coupling agent in step (b) preferably includes any compound without limitation so far as it has a functional group to activate carboxyl group of the biopolymer and derive acid-decomposable ester linkage or amide linkage reaction with the insoluble drug and, more preferably, includes at least one or two of compounds having an imide group or amino group since such an imide group and amino group can stabilize an activated carboxyl group for a long period of time so as to increase the linkage yield. In case of using both of the compound having an imide group and the compound having an amino group at the same time, a molar ratio of the compound having an imide group to the compound having an amino group preferably ranges from 1: 0.5 to 3.0 in order to stabilize the activated carboxyl group.

[50] More particularly, the compound having an imide group preferably includes

1,3-dicyclohexyl carbodiimide (DCQ while the compound having an amino group preferably includes 4-dimethylaminopyridine (DMAP).

[51] According to the present inventive method, an amount of the insoluble biomolecules added to the biopolymer in step (Q may range from 0.01 to 30% (w/w).

[52] According to the present inventive method, the insoluble biomolecules in step (c) may include any compounds without limitation so far as they have precipitation properties and include, for example, insoluble drugs, insoluble biodegradable polymers, insoluble lipids, etc.

[53] More particularly, the insoluble drugs may include, for example: insoluble anticancer drugs selected from a group consisting of paclitaxel, methotrexate, doxorubicin, 5-fluorouradl, mitomycin-C, styrene maleic acid neocarzinostatin (SMANCS), dsplatin, carboplatin, carmustine (BCNU), dacarbazine, etoposide and daunomydn; anti- viral drugs; steroidal anti- inflammatory drugs; antibacterial agents; anti-fungal agents; vitamins; prostacyclin; anti-metabolites; mitotics; adrenaline antagonist; anticonvulsant drugs; anti-anxiety drugs; tranquillizer; anti-depressant agents; anesthetics; analgesics; anabolic steroids; immunosuppressive drugs; immune-stimulators; and mixtures thereof.

[54] The insoluble biodegradable polymer includes, for example, polylactic acid (PLA), polyglycolic acid (PGA), polylactic-co-glycolic acid (PLGA), polycaprolactone (PCL), dicarboxylic aliphatic polyester (PBsA), polyetheramide, polyester ure thane, etc.

[55] The insoluble lipids include, for example, fatty acids and phospholipids.

[56] According to the present inventive method, it is preferable that the insoluble biomolecules are added under an anhydrous N₂ atmosphere in step (c) so as to inhibit acid-decomposable esterification.

[57] The present inventive method may further comprise the step (d) of removing unreacted insoluble biomolecules and compositions of unreacted biopolymers and biodegradable poly (ethylene glycol) by dialysis of the reaction product obtained from step (c). Also, the method may further comprise the step (e) of collecting and lyophilizing a conjugate of the biopolymers and the insoluble biomolecules, after step (d).

[58] According to another aspect of the present invention, there is provided a complex of the biopolymers and the insoluble biomolecules prepared by the above method.

[59] Since the complex of the biopolymers and the insoluble biomolecules according to the present invention forms micelles by self-assembly thereof in an aqueous solution, insoluble ingredients free from the micelles have pH-dependent degradable properties and exhibit remarkably stronger cytotoxicity to biopolymer receptor over-expressed cancer cells rather than to biopolymer receptor deficient cells. These results demonstrate that micelles are potentially useful for production of cell- specific treatment agents. Micelles mean microfine crystals used to form polymeric compounds.

[6D] With regard to the conjugate of the biopolymers and the insoluble biomolecules, examples of the biopolymers include genes, hydrocarbonate based polysaccharides such as hyaluronic acid (HA) or heparin, proteins, peptides or the like.

[61] The insoluble biomolecules may include insoluble drugs, insoluble biodegradable polymers or insoluble lipids. More particularly, the insoluble drugs include, for example: insoluble anti-cancer drugs selected from a group consisting of paclitaxel, methotrexate, doxorubicin, 5-fluorouracil, mitomydn-C, styrene maleic acid neocarzi- nostatin (SMANCS), dsplatin, carboplatin, carmustine (BCNU), dacarbazine, etoposide and daunomydn; anti-viral drugs; steroidal anti-inflammatory drugs; antibacterial agents; anti-fungal agents; vitamins; prostacyclin; anti-metabolites; mitotics; adrenaline antagonist; anti-convulsant drugs; anti-anxiety drugs; tranquillizer; antidepressant agents; anesthetics; analgesics; anabolic steroids; immunosuppressive drugs; immune-stimulators; and mixtures thereof.

[62] The insoluble biodegradable polymer includes, for example, PLA, PGA, PLGA,

PCL, PBsA, polyetheramide, polyester urethane, etc.

[63] The insoluble lipids include, for example, fatty adds and phospholipids.

[64] Hereinafter, the present invention will be described in detail through the following examples and experimental examples with reference to the accompanying drawings. However, these are intended to illustrate the invention as preferred embodiments of the present invention and do not limit the scope of the present invention.

[65] EXAMPLES 1 TO 4 : Preparation of HA/dmPEG complex salt and solubilization of the complex salt

[66] Ig of hyaluronic add (HA) sodium salt (MW: 17kDa) purchased from Lifecore

Biomedical (Chaska, MN) was dissolved in 100ml of deionized water, dialyzed for 24 hours (MWCO (molecular weight cut-off): IkDa) and lyophilized to form a desalted HA product.

[67] As shown in Fig. 1, 0.5wt. parts (Example 1), lwt. part (Example 2), 5wt. parts

(Example 3) and 10wt. parts (Example 4) of polyethylene glycol dimethyl ether (dmPEG: MW: 200CDa) were added to the desalted HA product, respectively, and each of the mixtures was added to 25ml of deionized water. The solution underwent lyophilization after thoroughly stirring, to prepare an anhydrous HA/dmPEG complex salt.

[68] 600mg of the lyophilized HA/dmPEG complex salt was added to 5ml of anhydrous

DMSO available from Sigma- Aldrich (St. Louis, MO) under an anhydrous N₂ atmosphere. After strongly agitating the above solution at 8O⁰C for 2 hours, HA/dmPEG nano- complex solubilized in anhydrous DMSO was obtained.

[69] EXAMPLES 5 TO 8 : Preparation of HA-paclitaxel complex

[70] As shown in Fig. 1, 1,3-dicyclohexyl carbodiimide (DCQ/4-dimethylamino pyridine

(DMAP) in 0.5, 1.0, 3.0 and 3.0 molar ratios were added to 600mg of HA/dmPEG mixture with a weight ratio of about 5 (dmPEG/HA), respectively, and each of the mixtures was dissolved in 5ml of anhydrous DMSO.

[71] After activation of carboxyl group in the HA solution by agitating the same for 1 hour, different amounts (10 and 20mg) of paclitaxels purchased from TCI (Tokyo, Japan) were dissolved in ImI of anhydrous DMSO, then, gently added to the above solution by means of a syringe under an anhydrous N₂ atmosphere.

[72] Table 1 [Table 1]

[Table ]

Combination of HA-paclitaxel

[73] Next, a solution was obtained by stirring the prepared mixture at 4O⁰C for 2 days and dialyzed by using a dialysis membrane (MWCO: 350CDa) in DMSO for 1 day and/or in deionized water for 3 days, in order to remove unreacted paclitaxel and dmPEG. The collected HA-paclitaxel complex was subjected to lyophilization for 3 days to obtain a complete HA-paclitaxel complex product.

[74] Referring to Fig. 1, it was found that hydroxyl group of paclitaxel is directly linked to carboxyl group by DCC/DMAP as a coupling agent to produce the HA-paclitaxel complex which contains acid-degradable ester bonds. The present invention adopted dimethyl-PEG (dmPEG) for HA solubilization in DMSO, instead of dihydroxyl-PEG, so as to avoid undesirable bonding of hydroxyl terminal PEG to HA.

[75] EXAMPLES 9 TO 12 : Preparation of HA-PLGA complex

[76] Similar to the procedure for HA-paclitaxel complex, 1,3-dicyclohexyl carbodiimide

(DCQ/4-dimethylamino pyridine (DMAP) with molar ratio of 3.0 was added to 600mg of HA/dmPEG mixture with a weight ratio of about 5 (dmPEG/HA) and the mixture was dissolved in 5ml of anhydrous DMSO.

[77] Dfferent amounts of polylactic-co-grycolic aid (PLGA: MW: 500CDa) available from Waco (Tokyo, Japan) were dissolved in ImI of anhydrous DMSO and each of these solutions was slowly added to the previously prepared solution by a syringe under an anhydrous N₂ atmosphere.

[78] A solution was obtained by stirring the prepared mixture at 4O⁰C for 2 days and dialyzed by using a dialysis membrane (MWCO: 350CDa) in DMSO for 1 day and in deionized water for 3 days, in order to remove unreacted polylactic-co-gly colic acid and dmPEG.

[79] The collected HA-PLGA complex was subjected to lyophilization for 3 days to obtain a complete HA-PLGA complex product. [80] Table 2 [Table 2] [Table ] Combination of HA-PLGA

[81] EXPERIMENTAL EXAMPLE 1: Identification of solubility of HA/dmPEG complex salt in DMSO [82] In order to identify solubility of HA/dmPEG complex salt solubilized as in Examples 1 to 4, a spectrophotometer (UV- 1601, Shimadzu, Japan) was used to measure trans- mittance of HA/dmPEG complex salt in DMSO at 400nm and determine solubility of HA/dmPEG complex salt in DMSO as a function of amount of dmPEG to be added. The results are shown in Fig. 2.

[83] Fig. 2 is a graph illustrating transmittance of DMSO solution, as a function of amount of dmPEG/HA in terms of weight ratio, and a parenthetic photograph shows the DMSO solution containing dmPEG/HA mixture, which represents parts pointed to by arrows (1, 2) in the graph.

[84] Dmension of HA/dmPEG complex salt measured by a conventional dynamic light scattering technology known in Int. Pharm. Res. was about 120+6.3nm, which is too small to scatter visible light. As a result, a clear and homogeneous solution can be produced.

[85] EXPERIMENTAL EXAMPLE 2: ¹H-NMR spectrum analysis of HA-prclitaxel [86] Four different HA-paclitaxel complexes prepared in Examples 5 to 8 were subjected to analysis of ¹H-NMR spectrum obtained by a Bruker 400 MHz NMR spectrometer (Bruker, Germany) and using D₂O and DMSO-d₆. The results are shown in Fig. 3. [87] Herein, an amount of paclitaxel combined to HA was measured by HPLC (1100 series, Agilent Technologies, Palo Alto, USA) using a reversed-phase column (Waters Spherisorb ODS2: 4.6mm IDx250mm) with a mobile phase consisting of acetonitrile/ water (a ratio by volume of 50/50) flowing at a flow rate of 0.8ml/min. An elution peak was observed at 227nm.

[88] Referring to Fig. 3, for D₂O solvent, a strong acetyl (-NHCOCH₃ ) peak was observed at 1.86ppm while there were peaks for glucoside Η ( 10H) at 3.0 to 4.0ppm and for anomeric Η (2H) at 4.30 to 4.40ppm, respectively. Conversely, characteristic peaks of paclitaxel became significantly reduced, for example, multiplets in an aromatic ring ranging from 6.75 to 7.05ppm and 7.85 to 8.15ppm.

[89] When DMSO-d₆ was used as the solvent, the characteristic peaks of paclitaxel were obviously observed in ¹H-NMR spectrum while HA specific acetyl peak and the reduced anomeric H ( 2H) peak disappeared at 1.86ppm and at 4.33ppm, respectively. Although the paclitaxel specific peak was observed in ¹H-NMR, it is difficult to evaluate paclitaxel combined with HA due to blocking and de-blocking of the paclitaxel specific peak and the acetyl specific peak.

[90] For culturing a HA-paclitaxel complex in an aqueous solution, it is expected that hydrophobic interaction between paclitaxels induces aggregation of paclitaxel and, otherwise, the above complex is freely exposed to an organic solvent.

[91] A combining amount of paclitaxel and a yield of each of samples were determined by HPLC using a mixture of acetonitrile and an aqueous co-solvent in relative ratio of 50:50 and the results are summarized in the above Table 1.

[92] It was demonstrated that, as an excess amount of DCC/DMAP in molar unit was increased, a combination yield of HA-paclitaxel reached about 30% and the paclitaxel complex sample with the greatest combining amount had more than 10% of paclitaxel content (% by weight). These data proved that a feed ratio of DCC/DMAP is a critical parameter for HA-paclitaxel complex.

[93] EXPERIMENTAL EXAMPLE 3: Characterization of micelles of HA-paclitaxel complex self-assembled in an aqueous solution

[94] Micelles of HA-paclitaxel complex formed in an aqueous solution were characterized by measuring hydraulic diameters thereof by means of Zeta-Plus (Brookhaven, NY) as a dynamic light scattering (DLS) instrument.

[95] From results of ¹H-NMR analysis, it was detected that there was an aggregation of paclitaxel in HA-paclitaxel complex. Size of the aggregation was measured by DLS (see A of Fig. 4). [96] Size measurement was carried out six times (n=6) at a concentration of HA-pa- clitaxel complex of 5.0mg/ml in deionized water at 25⁰C. Nanosized HA-paclitaxel micelles were visibly observed using AFM and TEM. In AFM images, it was found that 100/i6 of HA-paclitaxel solution (5.0mg/ml) existed on a transparent surface of mica, and the solution was dried out in the air overnight. The AFM images were obtained using a PSIA XE-100 AFM system (Santa Clara, CA) having a scan area of 5X5/M in non-contact mode.

[97] For TEM images, HA-paclitaxel micelles were analyzed by Zeiss Omega 912 TEM

(Carl Zeiss Go., Ltd., Germany). A TEM sample was prepared by depositing 20 /i6 of a HA-paclitaxel solution on a copper TEM grid with 300 mesh having a carbon film and air-drying the deposited grid at room temperature. CAC of a HA-paclitaxel complex was calculated using pyrene as a hydrophobic fluorescent probe.

[98] A pyrene crude solution dissolved in deionized water (Sigma- Aldrich, St. Louis,

MO) was prepared with a concentration of 6.0x10 ⁷M. To the crude solution, different amounts of the HA-paclitaxel complex in the range from 0.1μg/ml to lmg/ml were added. Fig. 4 shows results of monitoring an excitation spectrum of HA-paclitaxel micelles containing pyrene by a fluorescence spectrophotometer (Shimadzu, Japan) at an emission wavelength of about 390nm.

[99] The largest paclitaxel sample (Sample #4) containing HA-paclitaxel had average diameter of 196+9.6nm and a narrow diameter distribution. Formation of nanoparticles was identified from amphoteric copolymers, for example, fluorine copolymer, PEGI- PLGA and/or PLGA graft poly (L-lysine) resulted from self-assembly of amphoteric molecules through hydrophobic interaction.

[100] AFM and TEM images for visibly observed HA-paclitaxel nanoparticles were obtained (see B and C of Fig. 4). AFM images demonstrated that circular HA- paclitaxel nanoparticles had an average diameter of about 232+28.2nm (n=30), which was substantially identical to a result of DLS measurement.

[101] Alternatively, TEM images offered information on shapes and sizes of the circular

HA-paclitaxel nanoparticles (183+17.8nm, n=30). Further studies for nano-aggregation of HA-paclitaxel in an aqueous solution were achieved by determining CAC of HA- paclitaxel with use of a specific hydrophobic fluorescence probe such as pyrene. It is well known that pyrene may exist in lumen composed of amphoteric copolymers, and exhibit AIEE (aggregation induced enhanced emission) dependent on concentration of the copolymer in the aqueous solution. During an experiment, the excitation spectrum was measured and 1₃₃₉/1₃₃₄ intensity ratio of pyrene was evaluated (see D of Fig. 4). [102] With regard to increase of HA-paclitaxel concentration, increase of fluorescence intensity and red shift of pyrene were observed. In a graph for 1₃₃₉/1₃₃₄ intensity ratio, calculated CAC was 7.8μg/ml.

[103] EXPERIMENTAL EXAMPLE 4: pH-dependent effect of paclitaxel release from HA-paclitaxel complex micelles

[104] The prepared HA-paclitaxel complex was added to deionized water with a concentration of 10mg/ml to prepare a sample solution. Using 0.1M NaOH or HCl, multiple sample solutions with regulated pH values of pH 1, 3, 5 and 7 were prepared. After slowly stirring each of the sample solutions at 37⁰C for 1 hour, the solution was filtered using a syringe filter with a volume of 0.45/M.

[105] Fig. 5 shows results of monitoring amounts of paclitaxel released from the complex with different pH values by means of a RI (refractory index) detector (RI-71, Shodex, Japan).

[105] The present invention used acid-degradable ester linkage and specially worried about pH-dependent paclitaxel release from HA-paclitaxel nanoparticles. After culturing the sample under four different pH conditions, an amount of paclitaxel release was measured. In order to distinguish between signals of paclitaxel and HA-paclitaxel, a reversed-phase column was used together with the RI detector.

[107] An eluted solution from the reversed-phase column showed excellent peak separation ability depending on hydrophobic properties of HA-paclitaxel and paclitaxel. Referring to Fig. 5, it was found that separation of peaks of HA-paclitaxel and paclitaxel was initiated at acidic pH values and the amount of paclitaxel release depended on pH values during the culturing.

[108] On the other hand, there was only a single peak of HA-paclitaxel detected at pH 7.0. When the release of paclitaxel was increased, shift of HP-paclitaxel peak in the left direction was observed. HA-paclitaxel showed reduced hydrophobic properties as the degradation of paclitaxel was progressed.

[109] It is understood that such pH-dependent release improves absorption of paclitaxel by cancer cells, since the release of paclitaxel is significantly reduced near cancer regions with locally lowered pH values while endothermal release of paclitaxel is ai-celerated.

[110] EXPERIMENTAL EXAMPLE 5: In vitro anti-cancer activity of HA-paclitaxel complex micelles

[111] Using HCT-116 and MCF-7 cells as CD44 over-expressed cancer cell lines, transfer of HA-paclitaxel complex micelles as an in vitro cell specific-target was studied. NIH- 373 cells were used as a CD44 deficient cell line. [112] Prepared cells were spread on a 96-well plate with a cell density of IxIO⁴ cells per well and proliferated in RPMI media containing fetal bovine serum at 37⁰C for 24 hours. Cytotoxicity of HA-paclitaxel complex micelles was evaluated by treating the cells with HA-paclitaxel complexes having different concentrations at 37⁰C for 2 days.

For comparison, an alternative Taxol

® was used as a positive control. Cell viability was determined using a CCK- 8 cell viability analysis kit purchased from Ebjindo Laboratories (Kumamoto, Japan). [113] Using a co-focal laser microscope (LSM 510, Carl-Zeiss Inc., USA) and a flow cytometer (FACSCalibur, USA), cell apoptosis such as DNA fragmentation was monitored. After spreading HCT-116 cells on a chamber slide with a cell density of

1.OxIO⁵ cells/ml, the cells were treated using a Taxol

® formulation or a HA-paclitaxel micelle based formulation with an equivalent weight concentration of about lμg/ml in view of paclitaxel at 37⁰C for 24 hours.

[114] After fixing the cells with 1% para- formaldehyde, the cells were incubated with a concentration of 1x10⁶ cells/ml at 37⁰C for 30 minutes by using a PI (propidium iodide) staining solution available from Sigma-Aldrich (St. Louis, MO), which contains 0.25mg/mL of PI and O.lmg/mL of RNase A dissolved in PBS.

[115] The stained cells were subjected to a visible observation using a co-focal microscope at an excitation wavelength of about 543nm. For flow cytometry, the stained cells were collected then re-suspended in 1.5ml of PBS at pH 7.4. Analysis of PI fluorescence for each of nuclei of the cells was performed using CellQuest ® software (PharMingen, USA).

[116] Fig. 6 shows in vitro cytotoxicity of each of HA-paclitaxel and Taxol

® in response to three different cell lines, that is, (A) HCT-116, (B) MCF-7 and (Q NIH-373. These cell lines were selected to exhibit absorption ability of HA-paclitaxel nanoparticles altered by receptors.

[117] Referring to Fig. 6, it was found that HA-paclitaxel nanoparticles have efficient cytotoxicity to each of HCT-116 and MCF-7 while showing reduced cytotoxicity to NIH- 373. Measurement data demonstrated that CD44 over-expressed cell lines such as HCT-116 and MCF-7 optionally or selectively absorbed HA-paclitaxel nanoparticles, therefore, HA-paclitaxel nanoparticles exhibited high cytotoxicity(IC ₅₀) even with low drug concentration of less than O.lμg/ml.

[118] In order to identify cell apoptosis induction effect of HA-paclitaxel nanoparticles, more detailed investigations for HCT-116 cells were conducted through flow cytometry. Fig. 7 shows co-focal images of PI stained HCT-116 cells after treatment of the cells with (A) a control, (B) Taxol

® and (Q HA-paclitaxel. Also, Fig. 7 illustrates graphs for results of FACS analysis for cell apoptosis effect of (D) the control, (E) Taxol

® and (Q HA-paclitaxel to HCT-116 cells. Herein, the used HA-paclitaxel is a pa- clitaxel formulation containing paclitaxel in an equivalent weight of about lμg/ml. Pa- clitaxel induced cell apoptosis was identified by PI staining the cells and visibly monitoring shape change of nucleus such as DNA fragmentation.

[119] Referring to Fig. 7, when HCT-116 cells were treated using a control formulation free of paclitaxel (20μg/ml of HA), there was no cell apoptosis and stronger red fluorescence was uniformly detected in nuclei of HCT-116 cells (see A of Fig. 7). In contrast, HCT-116 cells cultured using Taxol

® or HA-paclitaxel nanoparticles represented obvious evidence of cell apoptosis including, for example, cleavage and/or fragmentation of nuclei into particles with higher or lower densities (see B of Fig. 7).

[120] It is presumed that activation of endogenous nucleotidase correlates to a process of apoptosis to divide chromosome DNA into oligonucleosome fragments. Degree of apoptosis was quantitatively analyzed using flow cytometry. Cytotoxic activity of paclitaxel is generally caused by stabilization effect of paclitaxel on polymerized microtubules, which are required for formation of spindles and/or cell division. Accordingly, it was proved that paclitaxel induces arrest of cell cycle in a G2/M phase and, finally, death of cells through apoptosis mechanism.

[121] Referring to D to F of Fig. 7, it was clearly found that HA-paclitaxel nanoparticles induced remarkable increase of G2/M cell populations (64.94%), compared to those of the control (16.12%) and Taxol

®

(31.17%). Such a result demonstrated that HA-paclitaxel nanoparticles can be easily absorbed into CD44 over-expressed cells and considerably improve apoptosis- induction effect. [122] Lastly, if applied as a paclitaxel carrier, HA-paclitaxel nanoparticles have an advantage of passively and/or actively targeting cancer cells.

[123] EXPERIMENTAL EXAMPLE 6: ¹H-NMR spectrum and FT-IR analyses of HA- PLGA

[124] HA-PLGA complex prepared in Example 11 was subjected to analysis of ¹H-NMR spectrum obtained by a Bruker 400 MHz NMR spectrometer (Bruker, Germany) and using D₂O and DMSOd₆. The result is shown in A of Fig. 8.

[125] Referring to A of Fig. 8, for D₂O solvent, a strong acetyl (-NHCOCH₃ ) peak was observed at 1.86ppm while there were peaks for glucoside Η ( WH) at 3.0 to 4.0ppm and for anomeric Η (2H) at 4.30 to 4.40ppm, respectively. Conversely, a characteristic peak of PLGA became significantly minimized in the range from 4.88 to 5.22ppm.

[126] When DMS0-d₆ was used as the solvent, the characteristic peak of PLGA was obviously observed in ¹H-NMR spectrum while HA specific acetyl peak and the reduced anomeric H ( 2H) peak disappeared at 1.86ppm and at 4.33ppm, respectively.

[127] In case that the ΗA-PLGA complex was cultured in an aqueous solution, it is expected that hydrophobic interaction between PLGAs induces aggregation of PLGA and, otherwise, the above conjugate is freely exposed to an organic solvent.

[128] Using FT-IR, it was determined whether there was a combination of ΗA-PLGA and the result is shown in B of Fig. 8. It was found that HA and PLGA have characteristic peaks, respectively. Especially, HA has a peak for hydroxyl group (OH) in a wider range from 2800 to 3800cm^"1 while PLGA has a C=O specific peak at about 2900cm -¹ and a C-H specific peak at about 1800cm ^Λ.

[129] It was found that HA-PLGA has characteristic peaks of both of HA and PLGA and, as a result, it can be determined whether HA-PLGA was combined together.

[130] EXPERIMENTAL EXAMPLE 7: Characterization of micelles of HA-PLGA complex self-assembled in an aqueous solution

[131] Micelles of HA-PLGA complex prepared in Example 11 were characterized by measuring hydraulic diameters thereof in an aqueous solution by means of Zeta-Plus (Brookhaven, NY) as a DLS instrument.

[132] From results of ¹H-NMR analysis, it was detected that there was an aggregation of PLGA in HA-PLGA complex. Size of the aggregation was measured by DLS.

[133] Size measurement was carried out six times (n=6) at a concentration of HA-PLGA complex of 2.0mg/ml in deionized water at 25⁰C. Measured dynamic diameter ranged from 150 to 300nm. Nanosized HA-PLGA micelles were visibly observed using AFM and TEM. In AFM images, it was found that 100 /i6 of a HA-PLGA solution (2.0mg/ml) existed on a transparent surface of mica, and the solution was dried out in the air overnight. The AFM images were obtained using PSIA XE-100 AFM system (Santa Clara, CA) having a scan area of 3X3/M in non-contact mode.

[134] For TEM images, HA-PLGA micelles were analyzed by Zeiss Omega 912 TEM

(Carl Zeiss Go., Ltd., Germany). A TEM sample was prepared by depositing 20 /i6 of the HA-PLGA solution (2.0mg/ml) on copper TEM grid with 300 mesh having a carbon film and air-drying the deposited grid at room temperature. CAC of a HA- PLGA complex was calculated using pyrene as a hydrophobic fluorescent probe.

[135] A pyrene crude solution dissolved in deionized water (Sigma-Aldrich, St. Louis,

MO) was prepared with a concentration of 6.0x10 ⁷M. To the crude solution, different amounts of the HA-PLGA complex in the range of 0.1μg/ml to lmg/ml were added. Fig. 9 shows results of monitoring excitation spectrum of HA-PLGA micelles containing pyrene by a fluorescence spectrophotometer (Shimadzu, Japan) at an emission wavelength of about 390nm.

[136] AFM and TEM images for visibly observed HA-PLGA nanoparticles were obtained (see A and B of Fig. 10). From AFM images in A of Fig. 10, it was demonstrated that circular HA-PLGA nanoparticles had an average diameter of about 282+20.8nm (n=30), which was substantially identical to a result of DLS measurement.

[137] Alternatively, TEM images offered information on shapes and sizes of the circular

HA-PLGA nanoparticles (243+27.8nm, n=30). Further studies for nano-aggregation of HA-PLGA in an aqueous solution were achieved by determining CAC of HA-PLGA with pyrene as a specific hydrophobic fluorescence probe.

[138] It is well known that pyrene may exist in lumen composed of amphoteric copolymers and exhibit AIEE dependent on concentration of the copolymer in the aqueous solution. During an experiment, the excitation spectrum was measured and I₃₃₉Zl₃₃₄ intensity ratio of pyrene was evaluated.

[139] With regard to increase of HA-PLGA concentration, increase of fluorescence intensity and red shift of pyrene were observed. In a graph for I₃₃₉ZI₃₃₄ intensity ratio, calculated CAC was 14.8μg/ml.

[140] EXPERIMENTAL EXAMPLE 8: Utility of HA-PLGA complex micelles as an anti- cancer drug delivery vector

[141] In order to investigate and identify anti-cancer drug delivery effect of HA-PLGA complex micelles which are an in vitro cell specific-target, HCT-116 cells were used as CD44 over-expressed cancer cell line.

[142] For addition of an anti-cancer drug to the HA-PLGA complex, HA-PLGA and dox- orubidn were dissolved in DMSO then dialyzed in distilled water to prepare an experimental sample that contained the anti-cancer drug in lumen of HA-PLGA complex micelles. Herein, addition yield of the drug was measured to be about 30%.

[143] Cells were spread on a 96-well plate with a cell density of lxlθ⁴cells per well and proliferated in RPMI media containing 10% by volume of fetal bovine serum at 37⁰C for 24 hours.

[144] Cytotoxicity of HA-PLGA complex micelles containing the anti-cancer drug was evaluated by treating the cells with HA-PLGA complexs having different concentrations at 37⁰C for 2 days. For comparison, an alternative doxorubicin in an aqueous solution was used as a positive control. Cell viability was determined using a CCK- 8 cell viability analysis kit purchased from Ebjindo Laboratories (Kumamoto, Japan).

[145] Using a co-focal laser microscope (LSM 510, Carl-Zeiss Inc., USA) and a flow cytometer (FACSCalibur, USA), cell specific adsorption of the anti-cancer drug contained in HA-PLGA was monitored. After spreading HCT-116 cells on a chamber slide with a cell density of 1.0x10⁵ cells/ml, the cells were treated using a solution containing doxorubicin or a HA-PLGA micelle based formulation with an equivalent weight concentration of about lμg/ml in view of doxorubicin at 37⁰C for 30 minutes or 2 hours, respectively.

[146] After fixing the cells with 1% para- formaldehyde, the cells were subjected to a visible observation using a co-focal microscope at an excitation wavelength of about 543nm. For flow cytometry, the fixed cells were collected then re-suspended in 1.5ml of PBS at pH 7.4. Analysis of fluorescence for each of the samples was performed using CellQuest ® software (PharMingen, USA).

[147] Fig. 11 shows transfer effect of anti-cancer drugs to HCT-116 cell line by HA-PLGA complex micelles as an anti-cancer drug delivery vector, which demonstrated excellent absorption ability of HA-PLGA nanoparticles containing doxorubicin compared to doxorubicin in an aqueous solution.

[148] Referring to Fig. 11, it was found that HA-PLGA nanoparticles containing anticancer drug have efficient cytotoxicity to HCT-116 cells, especially, have superior cytotoxicity at lower concentration of doxorubicin than that of doxorubicin in an aqueous solution. This result proved that HA-PLGA nanoparticles can exhibit high cytotoxicity (IC₅₀)even with low drug concentration.

[149] In order to identify drug delivery effect of HA-PLGA nanoparticles containing anti- cancer drug, more detailed investigations for HCT-116 cells were conducted through co-focal microscopy and flow cytometry. Fig. 12 shows co-focal images of HCT-116 cells after treatment of the cells with (A) doxorubicin and (B) HA-PLGA containing doxorubicin for 2 hours, and after treatment of the cells with (Q doxorubicin and (D) HA-PLGA containing doxorubicin for 30 minutes.

[150] Referring to Fig. 12, it was found that a large amount of drug was delivered into the cells when both of the cells were treated by doxorubicin and HA-PLGA containing doxorubicin, respectively, for 2 hours, as in (A) and (B) of Fig. 12. Conversely, in case of treating the cells with each of the above samples for 30 minutes, only HA-PLGA containing doxorubicin delivered the drug into the cells.

[151] From these results, it was understood that HCT-116 cells have MDR (multi-drug resistance) to doxorubicin and this MDR can be reduced if HA-PLGA is used as a drug delivery vector.

[152] Fig. 13 is graphs illustrating results of FACS analysis of differences in drug delivery between a formulation with HA addition and another formulation without HA addition in order to identify HA specific drug delivery effect. The doxorubicin formulation contains doxorubicin in an equivalent weight of about lμg/ml. By monitoring amount of the drug increased in the cells, the drug delivery effect of HA-PLGA containing anti-cancer drug was determined.

[153] Referring to Fig. 13, when HCT-116 cells were treated using HA-PLGA containing doxorubicin, it is obviously understood that the drug delivery effect is clearly distinguished from that of a formulation without HA in an aqueous solution.

[154] The above results proved that although HA-PLGA nanoparticles are easily absorbed into CD44 over-expressed cells, HA addition to an aqueous solution induces a competitive inhibition, which further causes the drug delivery effect to be reduced. Consequently, HA-PLGA nanoparticles are introduced into the cells by ligand-receptor reaction between HA and CD44 cells. Industrial Applicability

[155] As described in detail above, the present invention provides a method for preparing a complex of biopolymers and insoluble biomolecules, characterized in that the hy- drophilic biopolymers can be solubilized in a variety of organic solvents and the sol- ubilized biopolymers can be combined with different hydrophobic drugs, fatty acids or synthetic polymers, thereby being effectively applied in chemical industries including, for example, pharmaceutical industry, food industry, etc.

[156] While the present invention has been described with reference to the above preferred embodiments, it will be understood by those skilled in the art that various modifications and variations may be made therein without departing from the scope of the present invention as defined by the appended claims.

Claims

[1] A method for preparing a complex of biopolymers and insoluble biomolecules, comprising the steps of:

(a) admixing a hydrophilic biopolymer with biodegradable poly (ethylene glycol) polymer in an aqueous solution after removing salts of the hydrophilic biopolymer to prepare a conjugate of the hydrophilic biopolymer and the biodegradable poly (ethylene glycol), lyophilizing the conjugate and dissolving the lyophilized conjugate of the hydrophilic biopolymer and the biodegradable poly (ethylene glycol) in an organic solvent to prepare nano-conjugate;

(b) reacting the solubilized nano-conjugate solution of the biopolymer and the biodegradable poly (ethylene glycol) in the presence of a coupling agent to activate the biopolymer; and

(c) adding insoluble biomolecules, which were dissolved in an alternative organic solvent, to the conjugate solution with activated polymer to derive a reaction between them.

[2] The method according to claim 1, wherein the hydrophilic biopolymers comprise at least one selected from a group consisting of genes, hydrocarbon based polysaccharides such as hyaluronic add (HA) or heparin, protein and peptide.

[3] The method according to claim 1, wherein salts of hydrophilic biopolymers are removed by dialysis or ethanol precipitation.

[4] The method according to claim 1, wherein the biodegradable poly (ethylene glycol) polymer comprises at least one selected from a group consisting of poly (ethylene glycol) having hydroxyl group, alkyl modified PEG substituted with alkyl group, amine modified PEG substituted with amine group, thiol modified PEG substituted with thiol group, carboxyl modified PEG substituted with carboxyl group, acryl modified PEG substituted with acryl group, linear PEG and branched PEG.

[5] The method according to claim 4, wherein the alkyl modified PEG is dimethyl

PEG.

[6] The method according to claim 2, wherein genes comprise at least one selected from a group consisting of DNA, plasmid genes, anti-sense oligonucleotides, siRNA and RNA.

[7] The method according to claim 1, wherein the organic solvents comprise at least one selected from a group consisting of methylene chloride, chloroform, acetone, dimethyl sulfoxide, dimethyl formamide, N-methyl pyrrolidone, dioxane, tetrahydrofuran, ethyl acetate, methylethyl ketone, acetonitrile, methanol, and ethanol.

[8] The method according to claim 1, wherein a mixing ratio by weight of the hy- drophilic biopolymer and the biodegradable poly (ethylene glycol) polymer in step (a) ranges from 1:1 to 1:1,000 (w/w).

[9] The method according to claim 1, wherein the coupling agent in step (b) comprises a compound having functional group to activate carboxyl group of the biopolymer and derive acid-decomposable ester linkage or amide linkage reaction with the insoluble drug.

[10] The method according to claim 9, wherein the coupling agent in step (b) comprises one or two of compounds having an imide group and amino group.

[11] The method according to claim 10, wherein the compound having an imide group comprises 1,3-dicyclohexyl carbodiimide (DCQ and the compound having an amino group comprises 4-dimethylaminopyridine (DMAP).

[12] The method according to claim 10, wherein a molar ratio of the compound having an imide group to the compound having an amino group ranges from 1 : 0.5 to 3.0.

[13] The method according to claim 1, wherein an amount of the insoluble biomolecules added to the biopolymer in step (Q ranges from 0.01 to 30% (w/w).

[14] The method according to claim 1, wherein the insoluble biomolecules in step (c) comprise insoluble drugs, insoluble biodegradable polymers or insoluble lipids.

[15] The method according to claim 14, wherein the insoluble drugs comprise at least one selected from a group consisting of insoluble anti-cancer drugs selected from a group consisting of paclitaxel, methotrexate, doxorubicin, 5-fluorouradl, mitomycin-C, styrene maleic acid neocarzinostatin (SMANCS), dsplatin, car- boplatin, carmustine (BCNU), dacarbazine, etoposide and daunomydn; anti-viral drugs; steroidal anti-inflammatory drugs; antibacterial agents; anti-fungal agents; vitamins; prostacyclin; anti-metabolites; mitotics; adrenaline antagonist; anticonvulsant drugs; anti-anxiety drugs; tranquillizer; anti-depressant agents; anesthetics; analgesics; anabolic steroids; immunosuppressive drugs and immune- stimulators .

[16] The method according to claim 14, wherein the insoluble biodegradable polymer comprises at least one selected from a group consisting of polylactic acid (PLA), polyglycolic add (PGA), polylactic-oo-glyoolic add (PLGA), polycaprolactone (PCL), dicarboxylic aliphatic polyester (PBsA), polyetheramide and polyester urethane.

[17] The method according to claim 14, wherein the insoluble lipids comprise at least one selected from a group consisting of fatty adds and phospholipids.

[18] The method according to claim 1, wherein the insoluble drugs are added under an anhydrous N₂ atmosphere in step (c).

[19] The method according to claim 1, further comprising the step (d) of removing unreacted insoluble drugs and compositions of unreacted biopolymers and biodegradable poly (ethylene glycol) by dialysis of the reaction product obtained from step (c).

[20] The method according to claim 19, further comprising the step (e) of collecting and lyophilizing a conjugate of the biopolymers and the insoluble drugs, after step (d).

[21] A complex of the biopolymers and the insoluble biomolecules prepared by the method defined in any one of claims 1 to 20.

[22] The complex according to claim 21, wherein the biopolymers comprise at least one selected from a group consisting of genes, hydrocarbon based polysaccharides such as hyaluronic add (HA) or heparin, protein and peptide.

[23] The complex according to claim 21, wherein the insoluble biomolecules comprise insoluble drugs, insoluble biodegradable polymers or insoluble lipids.

[24] The complex according to claim 23, wherein the insoluble drugs comprise at least one selected from a group consisting of insoluble anti-cancer drugs selected from a group consisting of paclitaxel, methotrexate, doxorubidn, 5-fluorouradl, mitomydn-C, styrene maleic add neocarzinostatin SMANCS, dsplatin, car- boplatin, carmustine BCNU, dacarbazine, etoposide and daunomydn; anti-viral drugs; steroidal anti-inflammatory drugs; antibacterial agents; anti-fungal agents; vitamins; prostacyclin; anti-metabolites; mitotics; adrenaline antagonist; anticonvulsant drugs; anti-anxiety drugs; tranquillizer; anti-depressant agents; anesthetics; analgesics; anabolic steroids; immunosuppressive drugs and immune- stimulators .

[25] The complex according to claim 23, wherein the insoluble biodegradable polymer comprises at least one selected from a group consisting of polylactic add (PLA), polyglycolic add (PGA), polylactic-co-glycolic add (PLGA), polycaprolactone (PCL), dicarboxylic aliphatic polyester (PBsA), polyetheramide and polyester urethane.

[26] The complex according to claim 23, wherein the insoluble lipids comprise at least one selected from a group consisting of fatty acids and phospholipids.