PHARMACOKINETIC STUDIES ON THE PERCUTANEOUS ABSORPTION OF DIETHYLAMINE SALICYLATE CREAM FROM HUMAN SKIN

Diethylamine salicylate (DEAS) cream was spread with rubbing on the inner part of two arms. The total amount of salicylic acid and its metabolite in urine were determined with spectrophotometry. Based on the non-linear least square method, the experimental data were treated using NLFTZHU program fixed on TRS—80 Ⅱ microcomputer system. The pharmacokinetic analysis showed that the absorption rate of DEAS cream is normal zero order with the absorption constant of 25.45±10.70 mg/h(time lag is 5—8b), and the first order elimination rate constant was 0.375±0.124h^-1. The plasma levels, after a large single dose (3.5g) and a multiple dose administrations were computer-simulated. The maximum plasma levels range from 2 to 6 μg/ml. They are remarkable lower than minimum effective plasma level of salicylic acid (50μg/ml). Diethylamine salicylate cream seems to be only responsible for a topical therapeuic effect.