Formulation and Evaluation of Lipid Based Nanoparticles of Etravirine

Engineered nanoparticles have the potential to revolutionize the diagnosis and treatment of many diseases like HIV/AIDS. Etravirine is one of the key components of highly active antiretroviral therapy used for the treatment of HIV-1 infections. The aim of the present study was to formulate and evaluate nanostructured lipid carriers of etravirine, intended for targeted delivery to macrophages, using solvent emulsification - evaporation technique.  Estimates of drug solubility were employed for selection of solid lipids, liquid lipids and stabilizers for the preparation of NLCs. Design of experiments was used to optimize the formulation with respect to drug-lipid ratio and concentration of stabilizer in the external phase using 32 full factorial design. Particle size of the carriers and drug release characteristics were the responses which were set to suitable levels for optimization. The optimized formulation was prepared and characterized for size, poly dispersity index, zeta potential, entrapment efficiency and appearance. The nanostructured lipid carriers of etravirine were prepared using stearylamine and glyceryl monostearate as solid lipids, Capryol 90 as liquid lipid and polyvinyl pyrrolidone as stabilizer. All experimental batches showed high drug loading efficiencies nearing 99%, indicating that etravirine remained closely associated with the lipids. The nanostructured lipid carriers displayed a zeta potential of -10.1 mv and a particle size of 261.6 nm with a polydispersity index of 0.374. In vitro release of etravirine from the optimized formulation at 2 h was 9% indicative of a low burst; and 56% of the entrapped drug was released after 24 h, suggesting prolonged release characteristics. Thus, etravirine loaded lipidic nanoparticles with potential for targeting cellular reservoirs of the AIDS virus such as macrophages were successfully developed. Keywords: Etravirine, Nanostructured lipid carriers, full factorial design