Establishment of the Measuring Tacrolimus Concentration in the Skin, and Application to Study on the Vehicle for Percutaneous Absorption

Abstract

Tacrolimus (FK506) ointment has a good therapeutic effect on atopic dermatitis. The efficacy of Tacrolimus ointment, however, depends on the percutaneous adsorption of tacrolimus. To examine the influence of the ointment base on the percutaneous adsorption of tacrolimus, we performed a quantitative analysis of tacrolimus in the skin using an IMX (microparticle enzyme immunoassay) system. We prepared tacrolimus ointments using five kinds of ointment bases, i.e., Carbopol gel, White Petrolatum, Hydrophilic Ointment, Plastibase and Macrogol ointment. The concentration of tacrolimus in the rat abdominal skin were then determined 14 hours after the topical application of the different ointments to the rat skin by using the IMX system, and the effect of the various ointment bases was thus evaluated. As a result, the amount of tacrolimus in the skin measured 14 hours after topical application was as follows : Carbopol gel >White Petrolatum >Hydrophilic Ointment≅Plastibase > Macrogol ointment.