Permeation of Diclofenac Salts through Silicone Membrane: A Mechanistic Study of Percutaneous Absorption of Ionizable Drugs

Abstract

To understand the mechanism of percutaneous absorption of ionizable drugs, diclofenac salts (DM: M = Li, Na, K, NH4, N(Me)4) as hydrophilic drugs were compared to free diclofenac acid (DH), a hydrophobic drug. DNa showed the highest permeability coefficient among DMs. The experimental diffusion coefficient through the silicone membrane (Dm) was compared with the calculated diffusion coefficient for an ion pair molecule (Dmpair) of DM. This may suggest that the existence of the lipid pathway of the DMs is the same as the DH. © 1994, The Pharmaceutical Society of Japan. All rights reserved.