Accumulation of lauric acid in skin as an enhancer for the percutaneous absorption of thiamine disulfide.

The permeation and accumulation of lauric acid (12:0) in rat skin as an enhancer for the percutaneous absorption of thiamine disulfide (TDS), using propylene glycol as a vehicle, were determined in vitro. 12:0 barely permeated through skin, and accumulated in skin. The accumulated amount increased increasing concentrations in the vehicle (1-20%). The proportion of the accumulation to total dose was highest at a dose of 5%. A positive relationship was found between the accumulated amount of TDS and 12:0. It was suggested that the penetration of 12:0 into skin contributes to the enhanced partition of TDS to skin.