Abstract
3-l-menthoxypropan-1, 2-diol (MPD), which is a derivative of l-menthol, and l-menthol enhance the penetration of indomethacin (IM) through hairless rat (HR) skin. It is well known that degree of enhancement differs with skin type, so we studied the enhancement of MPD and l-menthol on the penetration of IM through Yucatan micropig (YMP) skin. Ethanol (40%) containing 0.5% IM and 3% enhancer was applied to the donor phase of a modified Franz-type cell. The permeation rate of IM through YMP skin without enhancer was 1.7 μg/cm2/hr, which was about 1/3 that through HR skin. In the presence of MPD or l-menthol the rate of IM permeation through YMP skin were 2.5 and 5.6 μg/cm2/hr, respectively, much lower than through HR skin, 90 and 144 μg/cm2/hr. IM concentration in the skin without enhancer was 240 μg/g, with MPD, 380 μg/g and with l-menthol, 490 μg/g. MPD and l-menthol concentrations in the skin were 2.9 and 2.2 mg/g, respectively. It was considered that each enhancer was partitioned in the skin so that the partition coefficient of IM in the skin increased, though the increasing factor was smaller than that in the case of HR skin. The rate of IM permeation through epidermal membrane and stripped YMP skin were also determined.
