PROBLEM TO BE SOLVED: To obtain a therapeutic and prophylactic composition for pet animal parasites being capable of diffusing all over the whole body of a pet, only by applying the composition to a part of the body, causing no adverse effect on the appearance of the fur of the pet since it readily dries without crystallization and stickiness thereby particularly adequate to control and exterminate parasites in cats and dogs.SOLUTION: This therapeutic and prophylactic composition contains following components (a) through (d) in the solution form. The composition contains a compound represented by formula (I) in an amount of 1 to 20% (w/v), preferably 5 to 15% (w/v). (a) insecticidally active substance of formula (I) (b) a crystallization inhibitor, where this inhibitor gives the number of naked eye-observable crystals of 10 or less, when the crystallization inhibitor and the compound of formula (I) are dissolved each in an amount of 10% (w/v) in an organic solvent defined in (c) and the resultant solution A is dropped by 0.3 ml on a glass slide and left to stand for 24 hours at 20°C (c) the organic solvent having a dielectric constant of 10 to 35 and (d) an organic co-solvent having a boiling point of 100°C or lower and a dielectric constant of 10 to 40 that can be used as a drying promotor.COPYRIGHT: (C)2006,JPO&NCIPI【課題】動物の体の一部に投与するだけで体全体に拡散し、乾燥し、結晶化現象が起きず、毛皮の外観に影響を与えず、毛皮がべとつかないペット、特にネコとイヌに寄生する寄生虫を抑制および駆除する寄生虫の治療または予防用組成物。【解決方法】a)〔化1〕の殺虫活性物質、b)結晶化阻害剤(下記 c) で定義される溶媒中に式(I) の化合物を10%(W/V) 、この結晶化阻害剤を10%添加した溶液Aの 0.3 ml をガラススライドに付け、20℃で24時間放置した後にガラススライド上を肉眼で観察した時に、観察可能な結晶の数が10個以下)、c)誘電率が10~35の有機溶媒、d)沸点が100 ℃以下で誘電率が10~40の乾燥促進剤となる有機共溶媒。【化1】【選択図】なし
