Patent ID: 7736674

Claim:
A pharmaceutical composition for controlled release comprising microparticles including a polymeric carrier and one or more alpha interferons incorporated therein without loss of bioactivity, wherein the polymeric carrier consists of block copolymers constructed from poly(ethylene glycol) terephthalate (PEGT) and poly(butylene terephthalate) (PBT), wherein the average molecular weight of the polyethylene glycol (PEG) is from about 1,000 to about 2,000 daltons, wherein the block copolymer comprises from about 50 to about 95 wt.-% PEGT, wherein the composition comprises a dose of at least 20 MIU of alpha interferon that is released over a period of about 10 days to about 1 month, wherein the initial release within 4 hours is not more than about 10% of the incorporated dose of the one or more alpha interferons, and wherein at least about 80% of the one or more alpha interferons are released in monomeric, non-aggregated form.