US Patent 7101840 Polymeric drug formulations

A method of forming a polymeric drug formulation in which a water-soluble drug is blended with a water-insoluble tissue-compatible polymer that is miscible in the solid phase with the drug, and with a poly(alkylene oxide), in a solvent system capable of forming a homogeneous solution of the drug, the tissue-compatible polymer and the poly(alkylene oxide), after which the solution is added to a non-solvent for the drug, the tissue-compatible polymer and the poly(alkylene oxide), so that a microdomain-separated solid co-precipitate of the drug, the tissue-compatible polymer and the poly(alkylene oxide) is formed, wherein the poly(alkylene oxide) is blended in an amount effective to form phase-separated microdomains in said co-precipitate.