Formulation and optimization of ethosomes for transdermal delivery of ropinirole hydrochloride

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 optimized using 3(2) 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 Higuchi's and zero order kinetics. From the regression analysis, it was observed that independent variables had significant effect on response variables. Formulations were optimized using contour plot and response surface plot. The optimized formulation was found to be RS10 containing 30 % w/v ethanol and 4% w/v lecithin. The optimized formulation was evaluated for assay, particle characteristics, zeta potential, skin retention and stability. Ethosomal gel was prepared by incorporation 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.