A METHOD FOR THE PREPARATION OF CONTROLLED RELEASE COMPOSITIONS FOR INTERFERON BASED ON PEGT-PBT BLOCK COPOLYMERS

摘要

The present invention relates to a method for the preparation of a pharamceutical composition for controlled release comprising microparticles including a polymeric carrier and one or more interferons, wherein the polymeric carrier includes one or more block copolymers constructed from poly(ethylene glycol) terephthalate (PEGT) and poly(butylene terephthalate) (PBT), wherein the majority of the microparticles are substantially free of pores having a diameter of more than about 5 urn, comprising the steps of: (a) preparing an emulsion comprising (k) an aqueous inner phase comprising the active compound, and (l) an organic outer phase comprising the biodegradable polymer and at least one organic solvent; (b) solidifying the biodegradable polymer into microparticles by removing at least a fraction of the organic solvent from the emulsion prepared in step (a); (c) collecting and drying the microparticles formed in step (b), wherein step (b) is carried out by emulsifying the emulsion prepared in step (a) in a coherent aqueous phase to obtain a w/o/w-double emulsion, wherein the coherent aqueous phase comprises an osmotic agent