Biodegradable amphipathic copolymers

Claim 1

A pharmaceutically or veterinarily acceptable amphipathic block copolymer, which is self-dispersable in water to form a stable dispersion in water without the addition of any surfactant or other additive and has a minimum weight average molecular weight of 1000, selected from the group consisting of (a) non-cross-linked linear copolymers of the formula A m (BA) n or B m (AB) n ; and (b) non-cross-linked branched or graft block copolymers of the formula AB n or BA n wherein respectively A or B is a backbone polymer with n units of a monomer or polymer B or A respectively grafted onto it; wherein m is 0 or 1; n is an integer; wherein A is a pharmaceutically or veterinarily acceptable hydrophobic polymer which is biodegradable or hydrolytically unstable under normal physiological conditions and is selected from the group consisting of poly(D-, L- and DL-lactic acids); poly(D-, L-, and DL-lactides); polyglycolic acid; polyglycolide; poly-caprolactone; poly(3-hydroxybutyric acid); non-therapeutic hydrophobic polypeptides; polyacetals of the formula: ##STR5## wherein R is a hydrocarbon radical, and n is as previously defined; polycarbonates and polyorthoesters of the formula: ##STR6## wherein R and n are as previously defined; copolymers of the formula: ##STR7## wherein R and n are as previously defined; and copolymers derived from at least two monomers from which the above polymers are derived; and wherein B is a pharmaceutically or veterinarily acceptable hydrophilic polymer selected from the group consisting of polyvinylalcohol, polyvinylpyrrolidone, polyethylene glycol, polyacrylamide, polymethacrylamide, dextran, alginic acid, sodium alginate, gelatine, copolymers thereof, and polyoxyethylene/polyoxypropylene block copolymers.