Provesicular Based Colloidal Carriers for Transdermal Drug Delivery: Formulation Aspects and Bioavailability Enhancement of Acyclovir Proliposomal Gels

Background: Acyclovir (ACV) a 21-deoxy guanosine analogue effective against Herpes Simplex Virus (both type 1 and 2) and other viral diseases, mainly acts by inhibiting the viral DNA polymerase. The limited oral bioavailability of ACV (5-10%) requires higher dosage (400-800 mg), results in neurotoxicity and renal failure. Topically, the lower efficacy of ACV is attributed to inadequate drug permeation across the stratum corneum (SC). Methods: In present research, ACV containing proliposomes formulated using various ratios of lipid mixtures (Phosphotidyl choline and Cholesterol) by co acervation phase separation method. Results: The formulated vesicles are having the acceptable particle size range (385-616 nm). Other characters like morphological behaviour, zeta potential, polydispersity index and entrapment efficiency were evaluated. In vitro release studies reveal the controlled delivery of ACV from formed liposomes. Significant higher permeation parameter values [flux (Jss), permeability coefficient (Kp) and enhancement ratio (ER)] evaluated from all the formulations by performing ex vivo permeation studies using male wistar rats. 3.24 fold increment was observed in bioavailability of optimized formulation than control (oral suspension). The formulated ACV proliposomal gels were more stable when stored at 4°C. Conclusion: Improved bioavailability of ACV incorporated proliposomal gels than control reveals its potential in releasing of drug applied through transdermal route.