Effect of nerodilol, carvone and anethole on the in vitro transdermal delivery of selegiline hydrochloride.

The aim of the study was to investigate the effect of terpene enhancers (nerodilol, carvone or anethole) on the in vitro transdermal delivery of selegiline hydrochloride with a broad objective of developing a membrane-moderated transdermal therapeutic system (TTS). The in vitro permeation studies were carried across the rat epidermis from hydroxypropyl methylcellulose (HPMC) gel drug reservoir containing selected concentrations of nerodilol, carvone or anethole and selegiline hydrochloride. The amount of selegiline hydrochloride permeated during the 24 h of the study (Q24) from HPMC gel drug reservoir without terpene enhancer was 2169 +/- 50 microg/cm2 and the corresponding flux of the drug was 92 +/- 1 microg/cm2 x h. The amount of drug permeated and its flux increased with an increase in terpne concentration in HPMC gel drug reservoir. Nerodilol provided an approximately 3.2-fold increase in the flux of selegiline hydrochloride followed by carvone with a 2.8-fold increase, and anethole with a 2.6-fold increase. It is concluded that the terpene nerodilol, carvone and anethole produced a marked penetration enhancing effect on the in vitro transdermal delivery of selegiline hydrochloride that could possibly be used in the formulation of membrane-moderated TTS.