An injectable lipid-based suspension of buprenorphine providing one to seven days of pain alleviation has been developed. A method of manufacturing an injectable buprenorphine formulation providing about two to three days of pain therapy has been developed. A method of manufacturing an injectable buprenorphine formulation providing about one to seven, preferably two to three, days of pain therapy has been developed. The formulation is made by mixing buprenorphine, glyceryl distearate, and glyceryl tristearate dry powers with a liquid medium chain triglyceride (MCT), such as MIGLYOL® 812. The buprenorphine-Glycerol di and tristearate (Bup-GDS-GTS) is provided in a range of 0.2 to 20 mg Bup-GDS-GTS to one ml (gram) MCT.