Biodegradable polymer formulations for extended efficacy of botulinum toxin

A method of treating or preventing one or more symptoms of a diseases, disorder or cosmetic defects in a subject comprising administering to the subject an effective amount of a pharmaceutical composition comprising a plurality of polymer particles having uniformly dispersed therein between about 100 units and about 50,000 units of botulinum toxin complexed with a protein bulking agent and precipitated by a precipitating agent selected from the group consisting of L-histidine methyl ester, L-cysteine ethyl ester, Nα-(tert-butoxycarbonyl)-L-asparagine, L-proline benzyl ester, N-acetyl-L-tryptophan, gentisic acid, pentetic acid, octanoic acid, zinc chloride, and combinations thereof,

• wherein the precipitated botulinum toxin complexed with the protein bulking agent is washed with a wash solvent prior to encapsulation, wherein the wash solvent retains the toxicity of the botulinum toxin in a mouse lethality test at 48 hours at a dose of 10 units/injection and is selected from the group consisting of acetone, acetonitrile, dioxane, ethanol, 2-methoxy ethyl acetate, methoxy ethanol, ethoxy ethanol, butoxy ethanol, 2-propanol, propylene glycol methyl ether, ethanediol, 1,2-propanediol, tert-butyl alcohol, diethylene glycol, and combinations thereof, wherein the botulinum toxin is released in an effective amount over a period of weeks.