Biodegradable neurotoxin implants and methods of malting and using suchimplants are provided. Biodegradable neurotoxin implants include a neurotoxin,a biodegradable polymer component, and an acidity regulating component. Thebiodegradable polymer component is effective in controlling the release of theneurotoxin from the implant when the implant is located in a patients body.The acidity regulating component is effective in maintaining a pH of theimplant in a desired range that may be effective in stabilizing the neurotoxinas the implant biodegrades when the implant is located in a patients body. Inone embodiment, an implant includes a botulinum toxin, a biodegradablepolymer, and either monomers from which a biodegradable polymer is derived oroligomers including monomeric units substantially identical to a monomer fromwhich a biodegradable polymer is derived, or a combination of such monomersand oligomers. The oligomers and biodegradable polymer may be derived from asingle type of monomer. The implants disclosed herein may be administered to ahuman or animal patient in which a therapeutic effect is desired for prolongedperiods of time.
