Effect of sodium salicylate on in vitro percutaneous penetration of isopropamide iodide through mouse skin

Abstract

The effects of temperature, concentration, hydration, and sodium salicylate (SA) on the permeability of isopropamide iodide (ISP) through the excised abdominal mouse skin were investigated using the in vitro diffusion cell technique. The permeability of ISP was increased as the temperature of the diffusion medium increased, but was independent of ISP concentration, which suggests a simple diffusion process of ISP through the skin. It was increased about 2-fold by hydration of the skin for 3 days in normal saline. The permeability of ISP through the hydrated skin increased in the presence of SA. SA itself did not seem to affect the permeability of the skin for ISP in an irreversible manner, since the increase of the permeability was not seen after SA pretreatment of the skin followed by repeated washing. The apparent n-octanol/water partition coefficient (APC) of ISP increased as the concentration of SA in the aqueous phase increased. The permeability of ISP through the skin increased as the APC of it increased. The increase of the permeability in the presence of SA might be due to the formation of lipophilic ion-pair complex between ISP and SA.