Polyoxypropylene/polyoxyethylene copolymers with improved biological activity

The present invention relates to a preparation of polyoxypropylene/polyoxyethylene copolymer which has an improved toxicity and efficacy profile. The present invention also includes polyoxypropylene/polyoxyethylene block copolymers with a polydispersity value of less than approximately 1.05. The present invention comprises novel preparations of polyoxypropylene/polyoxyethylene copolymers which retain the therapeutic activity of the commercial preparations, but are substantially free from the undesirable effects which are inherent in the prior art preparations. Because the preparations of polyoxypropylene/polyoxyethylene copolymers which comprise the present invention are a less polydisperse population of molecules than the prior art polyoxypropylene/polyoxyethylene copolymers, the biological activity of the copolymers is better defined and more predictable.