an external preparation formulation superior in the transdermal absorbability has been desired as a new administration route of aripiprazole . transdermal absorption of aripiprazole has been enabled for the first time by appropriately combining aripiprazole and an organic acid . that is , it has been found that more superior transdermal absorbability can be achieved by forming a salt by using a compound showing lipophilicity within the range of − 1 . 5 - 2 , such as fatty acid and the like . it has been further found that the transdermal absorbability is remarkable improved by appropriately selecting the solvent composition . as a result , since a new dosage form of aripiprazole other than oral preparation has been developed , a new transdermal absorption preparation of aripiprazole can be provided .