a thermo - reversible thermoplastic pharmaceutical composition , comprising a botulinum toxin and a biocompatible poloxamer which provides thermoreversibility to the composition and additionally stabilizes the botulinum toxin , is described . the pharmaceutical composition can be administered to a patient as a liquid , and gels after administration into a sustained release drug delivery system from which the biologically active botulinum toxin is released over a multi - day period thereby localizing the drug as a depot and controlling release to enhance the therapeutic effect per dose .