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 glycofurol 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 preferably the veterinary acceptable liquid carrier comprises a co-solvent selected from the group consisting of acetone, acetonitrile, benzyl alcohol, butyl diglycol, dimethylacetamide, dimethylsulfoxide, dimethylformamide, N,N-diethyl-3-methylbenzamide , dipropylene glycol n-butyl ether, ethyl alcohol, isopropanol, methanol, phenylethyl alcohol, isopropanol, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, monomethylaceamide, dipropylene glycol monomethyl ether, liquid polyoxyethylene glycols, propylene glycol, N-methylpyrrolidone, 2-pyrrolidone, limonene, eucalyptol, diethylene glycol monoethyl ether, ethylene glycol, diethyl phthalate, polyethoxylated castor oil, methyl ethyl ketone, ethyl-L-Iactate, and a mixture of at least two of these co-solvents.
