The disclosure relates to topical localized formulation for the treatment or prophylaxis of parasite infestation in animals, which comprises an effective amount of at least one isoxazoline compound of the formula (I) and a pharmaceutically or veterinary acceptable liquid carrier vehicle comprising N,N-diethyl-3-methylbenzamide as a solvent； wherein the preferred isoxazoline compound of formula I is 4-[5-(3,5-dichlorophenyl)-5-trifluoromethyl-4,5-dihydroisoxazol-3-yl]-2-methyl-N-[(2,2,2-trifluoroethylcarbamoyl)-methyl]-benzamide, and wherein the preferred veterinary acceptable liquid carrier further comprises a co-solvent of at least two of acetone, ethyl-L-lactate, dimethyl sulfoxide, dimethylacetamide and glycofurol.
