Reaction between Salicylic Acid and Zinc Oxide in the Presence of Water.

Abstract

For the explanation of chemical changes and loss of dermatological activity of salicylic acid in external preparations containing salicylic acid and zinc oxide, systems composed of salicylic acid, zinc oxide, and water were investigated. By the determination of salicylic acid and zinc ion in the aqueous phase after an equilibrium state was attained, the formation of 1 : 1 and 2 : 1 salts of salicylic acid and zinc was ascertained quantitatively.