Transdermal drug delivery of imipramine hydrochloride. I. Effect of terpenes.

The objective of this investigation was to study the effect of different terpenes on IMH permeation in EtOH:W (2:1) system. Permeation studies of IMH were carried out with unjacketed Franz diffusion cells through rat skin. The flux of IMH with terpenes was found to be significantly higher than that in control (EtOH:W, 2:1) (P<0.05). Amongst all studied terpenes, menthol, terpineol, cineole and menthone were found to be effective permeation enhancers for IMH. It was found that the contribution of diffusivity in enhanced permeation of IMH was much higher in comparison to partitioning of IMH in skin with terpene treatment. Results of this study were explained with the help of H-bond breaking potential and self-association of terpenes. In order to elucidate the effect of terpenes on stratum corneum barrier FT-IR was used.