BIODEGRADABLE BLOCK COPOLYMER OF HYDROPHOBIC POLYMER AND HYDROPHILIC POLYMER AND COMPOSITION OF DRUG DELIVERY SYSTEM

摘要

PURPOSE: A biodegradable block copolymer of hydrophobic polymer and hydrophilic polymer and a composition of drug delivery system are provided. The copolymer has a low melting point and can be easily dissolved in organic solvent and a drug can be enclosed by the copolymer under low temperature. CONSTITUTION: The biodegradable block copolymer is characterized in that it consists of 20 to 80 wt.% of hydrophilic polymer polyalkyleneglycol having a molecular weight of 200 to 50,000 dalton and hydrophobic polymer poly(p-dioxanon) derivative having a molecular weight of 500 to 100,000 dalton, and is dissolved in a pharmaceutically acceptable solvent, in which the polyalkyleneglycol is polyethyleneglycol, monomethoxy polyethyleneglycol or the copolymer of ethyleneglycol and propyleneglycol, the poly(p-dioxanon) derivative is copolymer of poly(p-dioxanon) monopolymer, 1,4-dioxane-2-on and lactide, copolymer of 1,4-dioxane-2-on and glycolide, copolymer of 1,4-dioxane-2-on, glycolide and lactide, or copolymer of 1,4-dioxane-2-on and caprolactone, and the pharmaceutically accepted solvent is selected from methylenechloride, chloroform, ethanol, methanol, isopropanol, butanol, acetic acid, formic acid, ethyl acetate, methyl acetate, acetonitrile, acetone, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethyl acetamide, dimethyl sulfoxide, N-methylpyrrolidone, water and mixture thereof. The copolymer is represented by formula(1) RO-A-B-OH, (2) RO-B-A-B-OR, (3) RO-A-B-A-OR, or (4) RO-(A-B)N-OR, wherein R is hydrogen, methyl-, or acethyl- group; n is an integer of 1 or 100; A is a hydrophilic block and B is a hydrophobic block.