Polymeric Nanoparticles Loaded with Acyclovir: Formulation, Characterization and In-Vitro Drug Prolonged-Release Study

Abstract

Objectives: Acyclovir (ACV) is an antiviral drug, which requires frequent dosing regimen because of poor oral bioavailability and short half-life. In this study, ACV nanoparticles were formulated using ammonium methacrylates copolymers such as Eudragit RS 100 (Eud RS) and Eudragit RL 100 (Eud RL) to prolong release drug, and increase bioavailability. Methods: ACV loaded nanoparticles were prepared by the solvent replacement technique and then were characterized by particle size, distribution, entrapment efficiency, differential scanning calorimeter, transmission electron microscope, and in-vitro drug release. Results: It was found that as drug:polymer ratio changed from 1:2 to1:5, particle size and drug entrapment efficiency increased significantly. ACV– Eud RS loaded nanoparticles had a larger mean diameter of 363 nm in comparison to 200 nm of ACV- Eud RL nanoparticles. DSC results showed that in the prepared ACV-Eud RS nanoparticles, the drug was presented in the amorphous phase and may have been molecularly dispersed in the polymer matrix, but in the ACV-Eud RL nanoparticles, the drug was presented in the particles and homogeneously dispersed in the polymeric matrix. The entrapment efficiency of AVC-Eud RS nanoparticles was higher than that of ACV-Eud RL nanoparticles. In vitro drug release study showed that the ratios of released drug from ACV-Eud RS nanoparticles in the range from 58±3.8 to 62.9±4.6%, which was lower than those from ACV-Eud RL nanoparticles, in the range from 73.3±4.9 to 77.9±2.9%. The release was found to follow the Weibull model with a Fickian diffusion mechanism for both ACVEud RS and ACV- Eud RL nanoparticles. Conclusion: These results suggest that ACV nanoparticles based on Eud RS100 and Eud RL100 could prolong the release of the drug.