EP1716847B1 — Bioabsorbable pharmaceutical formulation comprising a PLGA copolymer

USPTO Abstract

An object of the present invention is to provide a bioabsorbable release-sustaining pharmaceutical formulation using a biodegradable release-sustaining base material which can prevent an effective component drug from being released too rapidly just after administration of the formulation and then allow continued release of the drug for at least one month at a defined rate, is provided. For the biodegradable release-sustaining base material, a lactic acid-glycolic acid copolymer (PLGA) with an adjusted distribution in molecular weight is used. For the biodegradable release-sustaining base material, a lactic acid-glycolic acid copolymer (PLGA) with an adjusted distribution in molecular weight is used. Specifically, the pharmaceutical formulation comprises the drug and the lactic acid-glycolic acid copolymer which has following fraction contents for their respective molecular weights determined by gel-permeation chromatography: a fraction content of less than 5% for a molecular weight of 40,000 or more, a fraction content of less than 20% for a molecular weight of 16,000 or more and less than 40,000, a fraction content of 45% or more for a molecular weight of 5,000 or more and less than 16,000, a fraction content of less than 10% for a molecular weight of 2,000 or more and less than 4,000, and a fraction content of 5% or more for a molecular weight of 500 or more and less than 1,500.