The present invention is directed to a depot composition for sustained release delivery ofbuprenorphine with enhanced stability and bioavailability. The composition is an injectable, low viscosity liquid and can form a depot in situ capable of delivering therapeutic level of buprenorphine over a period of time from one week to 3 months.本發明涉及用於持續釋放丁基原啡因的儲庫組合物,其具有增強的穩定性和生物利用性。該組合物是可注射的低黏度液體,並於體內形成丁基原啡因的儲庫,用以遞送一周至三個月具治療效能的藥物濃度。