Acyclovir (ACV) is an antiviral drug, used for treatment of herpes simplex virus infections with an oral bioavailability of only 10 to 20 % (limiting absorption in GIT to duodenum and jejunum),half-life about 3 hrs, soluble at acidic pH (pKa 2.27) and distilled water at 37ºC. Polymeric nano drug delivery systems of ACV have been designed and optimized. Poly (lactic-co-glycolic acid) (PLGA) (50:50) was used as polymer and Pluronic F68 was stabilizer. In vitro evaluation of prepared formulations showed drug entrapment up to 90.06 % and particle size from 395nm. Drug: Polymer ratio and concentration of stabilizer were found to influence the particle size and entrapment efficiency of ACV loaded PLGA nanoparticles (NPs). In vitro drug release studies indicated controlled and sustained drug release of drug for a period of 32 hours. In vivo evaluation was carried out for selected formulations in comparison with marketed tablet (Zovirax®) in rabbits. The AUC values for developed formulations clearly indicated two to three fold improvement in bioavailability of ACV when compared to Zovirax® tablets. These preliminary results indicate ACV NPs are superior to marketed tablet Zovirax® as particle size and release rate of entrapped drug is controlled, which results in enhanced bioavailability and probable decrease in dose and dosing frequency. Ultimately increasing adherence to drug therapy and patient comfort
