The effect of penetration enhancers on permeation kinetics of nitrendipine in two different skin models.

The purpose of this research was to evaluate the effect of penetration enhancers on permeation kinetics of nitrendipine (NTP) through two different skin models. The permeation profile and related kinetics parameters such as activity parameter, diffusion parameter, lag time, relative activity parameter and relative diffusion parameter of NTP was determined in presence of some novel and widely accepted permeation enhancers. Among all the more pronounced enhancing effect was obtained with oleic acid (OA) as it presented the highest permeability coefficient. The enhancement was found to be increased in the following order: Dimethyl sulphoxide (DMSO)<Isopropyl myristate (IPM)<Sodium lauryl sulphate (SLS)<Tween 20 (T20)<Myristic acid (MA)<Lauric acid (LA)<Capric acid (CA)<Tween 80 (T80)<Span 80 (S80)<Thyme oil (TO)<Palmarosa oil (PA)<Petitlgrain oil (PT)<Basil oil (BO)<Oleic acid (OA). The increase in drug permeation was attributed mainly to the decrease in diffusion path length. Essential oils and surfactant (span 80) have shown relative activity parameter (Kr value) well above unity and relative diffusion parameter (Dr value) almost equal or less than unity, which would be attributed to gradual increase in membrane permeability leading to higher permeation. Oleic acid is effective for augmenting skin permeation of NTP, with potential application in transdermal delivery of the drug.