Biodegradable compositions suitable for controlled release

Abstract

A special class of drug-depot forming triblock copolymers which are very suitable for the loading, containment and releasing of sensitive drugs such as proteins from biodegradable, injectable drug depots. How to visualize these depots for various imaging related purposes is described. A composition comprising a tri-block copolymer according to formula 1 B-A-B (1), wherein A stands for a linear poly-(ethylene glycol) block and wherein B stands for wherein B stands for a poly(lactide-co-ε-caprolactone) block, wherein the hydroxyl end-groups of the tri-block copolymer are at least partially acylated with an optionally substituted acyl having 2 to 12 C-atoms, C-atoms of the substituents included; an active ingredient, preferably a pharmaceutically active ingredient and a solvent, wherein the block ratio of the tri-block copolymer, which ratio is defined as the ratio between the sum of the average molecular weight of the B-blocks and the sum of the average molecular weight of the A-block ranges from 1.4 to 3.5. This composition is suitable for controlled release of a pharmaceutically active ingredient.