Formulation and evaluation of acyclovir loaded chitosan nanoparticles

Abstract

The present study was aimed to formulate and evaluate chitosan nanoparticles containing acyclovir as potential ophthalmic drug delivery system. The topical application of acyclovir as eye ointment remains a concern for effective management of various ocular viral diseases owing to poor ocular drug bioavailability. The acyclovir loaded chitosan nanoparticles were prepared by ionic gelation of chitosan with sodium tripolyphosphate anions. Differential Scanning Calorimetry (DSC) and Fourier Transform Infra-Red (FTIR) spectroscopy measurements were carried out on the nanoparticles and  on the  pure acyclovir and  chitosan polymer.  Five different formulations were prepared and evaluated for particle size, Zeta potential, scanning electron microscopy, entrapment and loading capacity, in vitro drug release profile. All the prepared formulations resulted in nano size in 150 - 250 nm and displayed spherical shape with Zeta potential of +33.2 to +42.8 mV. The encapsulation efficiency and loading capacity were 70% - 90% and 25% - 50% respectively. The acyclovir loaded chitosan nanoparticles displayed crystallinity than acyclovir. The in-vitro release profile of acyclovir from the nanoparticles showed a sustained release of the drug over a prolonged period of 24 hrs. Kinetic release profiles of acyclovir from nanoparticles appeared to fit best with Higuchi model with zero order and the non- Fickian diffusion mechanism. The in- vitro results reveal that ocular viral infections can be inhibited by the  nanoparticles more significantly than the drug in conventional dosage forms. Thus it can be conclusively stated that the acyclovir loaded chitosan nanoparticles suspension may be considered as an improved ophthalmic drug delivery system for the treatment of ocular viral infections.