Effect of essential oils as penetration enhancers for ibuprofen loaded transdermal gel formulations

The aim of the present study was to evaluate essential oils as penetration enhancers for transdermal gels using Ibuprofen as a model drug. Ibuprofen was formulated as a 5% carbopol gel. The amount of co-solvent (ethanol and propylene glycol) was optimized so as to obtain a homogenous gel. The prepared gels were evaluated for pH, spreading and homogeneity. Gel containing 5% drug, 0:15 proportion of ethanol: water and 1.5% carbopol was selected as base gel. The penetration of the gel was studied through cellulose membrane, egg shell membrane and rat skin. The gels containing different penetration enhancers were compared using various parameters like transdermal flux, permeability coefficient, and enhancement ratio and lag time. Anise oil was selected as the optimized essential oil for the gel formulations. The gel prepared using anise oil was studied for drug release kinetics and occlusivity. The gel was further studied for skin irritation in rat i.e. the formation of erythema and edema and compared with placebo gel and marketed formulation. The anise oil containing gel can be used to deliver therapeutically relevant doses of ibuprofen-like drugs.