Nicotinic Acid and Ethyl Nicotinate in Excised Human Skin

Abstract
A method is described for measuring the percutaneous absorption of radioactive nicotinic acid and ethyl nicotinate in excised human skin. It was found that there was approximately a 37,000-fold difference between the penetration of the two compounds. The effect of hydration on the penetration of ethyl nicotinate was measured and found to facilitate absorption about sixfold. The possible reasons for the great difference in penetration of these two compounds is discussed.