No 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, thereafter 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 increased from 1:2 to 1:5, particle size and drug entrapment efficiency increased significantly. ACV– Eud RS loaded nanoparticles had larger mean diameter of 363 nm in comparision 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, drug was presented in the particles and homogeneously dispersed in the polymeric matrix. The entrapment efficiency of AVC-Eud RS nanoparticles were higher than that of ACV-Eud RL nanoparticles. In vitro drug release study showed drug release in 10h of ACV-Eud RS nanoparticles in the range from 58±3.8 to 62.9 ±4.6%, which was lower than drug release of 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 ACV-Eud RS and ACV- Eud RL nanoparticles.