The present invention provides compositions and methods for extending therelease times and lowering the toxicity of pharmacologically active compounds.The compounds comprise a salt of the pharmacologically active compound with alipophilic counterion and a pharmaceutically acceptable water soluble solventcombined together to form an injectable composition. The lipophilic counterionmay be a saturated or unsaturated C8-C22 fatty acid, and preferably may be asaturated or unsaturated C10-C18 fatty acid. The compounds precipitate inaqueous environments. When injected into a mammal, at least a portion of thecomposition precipitates and releases the active compound over time. Thus, thecomposition forms a slowly releasing drug depot of the active compound in themammal. Therefore, the present invention enables one to provide a controlleddose administration of the active compound for a period of up to 15 days oreven longer. Many compounds can be administered according to the presentinvention including, but not limited to, tilmicosin, oxytetracycline,metoprolol, fluoxetine, roxithromycin, and turbinafine.
