Abstract
Percutaneous absorption and model membrane variations of melationin (MT) in aqueous-based propylene glycol and $2-hydroxypropyl-{\beta}-cyclodextrin $vehicles were investigatted. the excised hairless mouse skin (HMS) and two synthetic ethylene vinyl acetate (EVA) and microporous polyethylene (MPE) were selected as a model membrane. the solubility of MT was determined by phase equilibrium study. the vertical $Franz{\circledR}$ type cell was used for diffusion study. The concentration of MT was determined using reverse phse HPLC system. The MT solubility was the highest in a mixture of PG and $2-HP{\beta}CD$. The percutaneous absorption of MT through excised HMS increased as the solubility increased. However, the permeability coefficient decreased and then slightly increased in mixture of PG and $2-HP{\beta}CD$. On the other hand, both flux and permeability coefficient through EVA membrane decreased as the solubility increased. No MT was detected over 12 h after starting diffusion through MPE membrane. The flux of MT was dependent on the type of membrane selected. Flux of MT was greatest in excised HMS followed by EBA and MPE membrane. Flux of MT through EVA membrane was 5-20 times lower when compared to excised HMS. Interestingly, volumes of donor phase when MPE membrane was used, significantly increased during the study period. the HMS might be applicable to expect plasma concentration of MT in human subjects based on flux and pharmacokinetic parameters as studied previously. the current studies may be applied to deliver MT transdermally using aqueous-based vehicles and to fabricate MT dosage forms.