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
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.