Formulation and Optimization of Ethosomes for Transdermal Delivery of Ropinirole Hydrochloride

Abstract

The present study focuses on the formulation of ethosomal gel of ropinirole hydrochloride (ropinirole HCl), an anti-Parkinsonian drug, for delivery as a carrier for transdermal application. The ethosomes were prepared using different concentrations of phospholipids (2-5 % w/v), ethanol (20-50 % w/v), ropinirole HCl (5 % w/v) and water. They were op- timized using 32 full factorial designs to study the effect of independent variables, concentrations of ethanol and lecithin on dependent variables, entrapment efficiency and in-vitro drug release at 24 hrs. The drug release profile exhibited Higu- chi’s and zero order kinetics. From the regression analysis, it was observed that independent variables had significant ef- fect on response variables. Formulations were optimized using contour plot and response surface plot. The optimized for- mulation was found to be RS10 containing 30 % w/v ethanol and 4% w/v lecithin. The optimized formulation was evalu- ated for assay, particle characteristics, zeta potential, skin retention and stability. Ethosomal gel was prepared by incorpo- ration of optimized ethosomal suspension into gel base. The ethosomal gel was characterized for physical appearance, pH, content uniformity, rheological behaviour, skin-retention, in-vitro and in-vivo drug release and stability. From the results it can fairly be concluded that ethosomes are capable of delivering ropinirole hydrochloride into systemic circulation by transdermal route. The amounts thus delivered are also equitable to those delivered orally and are delivered at a rate slow enough to achieve longer blood levels.