Formulation of acyclovir-loaded solid lipid nanoparticles: design, optimization, and in-vitro characterization

The goal of this study was to design, optimize, and characterize Acyclovir-loaded solid lipid nanoparticles (ACV-SLNs) concerning particle size, zeta potential, entrapment efficiency, and release profile. Full factorial design (2(3)) was applied and the independent variables were surfactant type (Tween 80 and Pluronic F68), lipid type (Stearic acid and Compritol 888 ATO), and co-surfactant type (Lecithin and Sodium deoxycholate). The microemulsion technique was used followed by ultrasonication. The ACV-SLNs had a particle size range of about 172-542 nm. The polydispersity index (PDI) was found to be between 0.193 and 0.526. Zeta potential was in the range of -25.7 to -41.6 mV indicating good physical stability. Entrapment efficiency values were in the range of 56.3-80.7%. The drug release kinetics of the prepared formulations was best fitted to Higuchi diffusion model. After storing ACV-SLNs at refrigerated condition (5 +/- 3 degrees C) and room temperature (25 +/- 2 degrees C) for 4 weeks; we studied the change in the particle size, PDI, and zeta potential. The selected optimized formulation (F4) was containing Compritol, Pluronic F68, and Lecithin. These results indicated the successful application of this design to optimize the ACV-SLNs as a promising delivery system.