Formulation and Optimization of Eudragit RS PO‐Tenofovir Nanocarriers Using Box‐Behnken Experimental Design

The objective of present study was to develop an optimized polymeric nanoparticle system for the antiretroviral drug tenofovir. A modified nanoprecipitation method was used to prepare Eudragit RS PO nanoparticles of the drug. The effect of amount of polymer, surfactant concentration, and sonication time on particle size, particle distribution, encapsulation efficiency (EE), and zeta potential were assessed and optimized utilizing a three‐factor, three‐level Box‐Behnken Design (BBD) of experiment. Fifteen formulations of nanoparticles were prepared as per BBD and evaluated for particle size, polydispersity index (PDI), EE, and zeta potential. The results showed that the measured mean particle sizes were in the range of 233 to 499 nm, PDI ranged from 0.094 to 0.153, average zeta potential ranged from −19.9 to −45.8 mV, and EE ranged between 98 and 99%. The optimized formulation was characterized for in vitro drug release and structural characterization. The mean particle size of this formulation was 233 nm with a PDI of 0.0107. It had a high EE of 98% and average zeta potential of −35 mV, an indication of particle stability. The FTIR showed some noncovalent interactions between the drug and polymer but a sustained release was observed in vitro for up to 80 hours.