Amphiphilic block copolymer and polymeric composition comprising the same for drug delivery
The present invention relates to an amphiphilic block copolymer of a hydrophilic block and a hydrophobic block with a terminal hydroxyl group wherein the terminal hydroxyl group of the hydrophobic bock is substituted with a tocopherol or cholesterol group. It also relates to polymeric compositions capable of forming stable micelles in an aqueous solution, comprising the amphiphilic block copolymer and a polylactic acid derivative wherein one or more ends of the polylactic acid are covalently bound to at least one carboxyl group.
1. A block copolymer comprising hydrophilic A blocks and hydrophobic B blocks with a terminal hydroxyl group, wherein said terminal hydroxyl group of the hydrophobic block is substituted with tocopherol or cholesterol, wherein the hydrophilic A block is a member selected from the group consisting of polyalkylene glycols, polyvinyl alcohols, polyvinyl pyrrolidones, and polyacryl amides wherein the hydrophobic B block is a member selected from the group consisting of polylactides, polyglycolides, polycaprolactone, polydioxan-2-one, polylactic-co-glycolide, polylactic-co-dioxan-2-one, polylactic-co-caprolactone and polyglycolic-co-caprolacton.
2. The block copolymer according to claim 1 , which is an A-B type diblock copolymer or a B-A-B type triblock copolymer.
3. The block copolymer according to claim 1 , wherein the ratio of the hydrophilic A block to the hydrophobic B block is within the range of 30:70 to 97:3 by weight.
4. The block copolymer according to claim 1 , wherein the hydrophilic A block has a number average molecular weight of 200 to 50,000 Daltons.
5. The block copolymer according to claim 1 , wherein the hydrophobic B block has a weight average molecular weight of 50 to 50,000 Daltons.
6. A block copolymer, which is represented by the following formula:
R 1′ —O—[R 3′ ] x′ —[R 4′ ] m′ —[R 5′ ] n′ —C(═O)—(CH 2 ) x′ —C(═O)—O—R 2′ (I′)
wherein R 1′ is CH 3 —, H—[R 5′ ] n′ —[R 4′ ] m′ —, or R 2′ —O—C(═O)—(CH 2 ) x′ —C(═O)—[R 5′ ] n′ —[R 4′ ] m′ —;
R 2′ is tocopherol or cholesterol;
R 3′ is —CH 2 CH 2 —O—, —CH(OH)—CH 2 —, —CH(C(═O)—NH 2 )—CH 2 —, or
R 4′ is —C(═O)—CHZ′-O—, wherein Z′ is a hydrogen atom or methyl group;
R 5′ is —C(═O)—CHY″—O—, wherein Y″ is a hydrogen atom or methyl group, —C(═O)—CH 2 CH 2 CH 2 CH 2 CH 2 —O—, or —C(═O)—CH 2 OCH 2 CH 2 —O—;
l′ is an integer from 4-1150;
m′ is an integer from 1-300;
n′ is an integer from 0-300; and
X′ is an integer from 0-4.
7. A drug carrier comprised essentially of block copolymer according to claim 1 .