In-vitro release of acyclovir loaded Eudragit RLPO® nanoparticles for sustained drug delivery

In this present study the possibility to develop Eudragit RLPO® based nanoparticles of acyclovir was investigated in order to increase its efficacy because acyclovir has oral bioavailability of only 10-20% thus showing erratic absorption and bioavailability behaviour. The nanoparticles were prepared by nanoprecipitation technique. Pluronic F68 was used as stabilizer. The nanoparticles were characterized by particle size, entrapment efficiency, DSC, SEM, FTIR and in-vitro drug release. It was found that as drug:polymer (Acyclovir:Eudragit RLPO®) ratio increased from 1:1.5 to 1:2, particle size was increased significantly and drug entrapment also increased but thereafter, further increase in drug: polymer ratio showed reduced or insignificant change in the drug entrapment efficiency. DSC results showed that in the prepared nanoaprticles, the drug was present in the amorphous phase and may have been homogeneously dispersed in the polymer matrix. In vitro drug release study of formulations showed release in 24 h in the range 71.62 ± 1.72 to 93.25 ± 1.02%. The release was found to follow Higuchi model with non-Fickian diffusion mechanism for all batches. These preliminary results indicate that acyclovir loaded Eudragit RLPO® nanoparticles could be effective in sustaining drug release for a prolonged period.