595359 Disclosed is a stable formulation suitable for topical administration to cattle including a levamisole active ingredient and at least one active selected from the group known as macrocyclic lactones (for example abamectin, ivermectin, doramectin, eprinomectin, moxidectin and selamectin) with both of said actives being dissolved in a non-aqueous system including one or more solvents selected from the group comprising dimethyl acetamide, dimethyl isosorbide, diethyl phthalate and dimethyl phthalate. Also disclosed is a method for preparing the formulation including: (a) Dissolving at least one of either the levamisole active ingredient or the macrocyclic lactone active ingredient in at least one solvent selected from dimethyl isosorbide, dimethyl acetamide, diethyl phthalate and dimethyl phthalate (b) Adding a co-solvent or co-solvents if desired, and then the second active ingredient if not already dissolved in the solution or (a) Dissolving at least one of either the levamisole active ingredient or the macrocyclic lactone active ingredient in at least one solvent selected from the chemical groups comprising glyceryl acetates, pyrollidones, glycol ethers, glycol esters, glycerol formal, and alcohols. (b) Adding a co-solvent or co-solvents selected from dimethyl isosorbide, dimethyl acetamide, diethyl phthalate and dimethyl phthalate (c) Adding the second active ingredient if not already dissolved in the solution.
