Formulation Design and Development of Azilsartan Nano-emulsion for the Solubility Enhancement

The study aims to formulate and refine a nanoemulsion containing azilsartan to improve the solubility and bioavailability of antihypertensive drug, which has low water solubility. A factorial design technique was employed to develop 14 nanoemulsion formulations with varying amounts of olive oil, Tween 80, and PEG-400. Formulations were analyzed for particle size, Zeta Potential (ZP), pH, viscosity, and drug content. FTIR and DSC studies validated the compatibility of drug and excipient. The improved formulation (F12) demonstrated a mean particle size of 249 nm, a ZP of -22.3 mV, and a drug content of 98.38%. SEM and TEM analysis showed spherical droplets exhibiting smooth surfaces. In vitro release experiments indicated a sustained drug release, with 98.25% released over an 8-hour period. The stability investigations verified that the formulation maintained stability for three months under accelerated situations. Response surface methodology and contour plots indicated a robust design space where formulation parameters could be optimized to achieve desired quality attributes. The nano-emulsion approach successfully improved the aqueous solubility of azilsartan while maintaining physicochemical stability. This novel formulation strategy shows promise for enhancing the therapeutic efficacy of azilsartan and potentially other poorly water-soluble drugs. Further in vivo studies are warranted to evaluate the pharmacokinetic profile and bioavailability enhancement of the optimized azilsartan nanoemulsion formulation.