Positively charged self-nanoemulsifying oily formulations of olmesartan medoxomil: Systematic development, in vitro, ex vivo and in vivo evaluation.

ABSTRACT

The current research work explores the potential applications of cationic self-nanoemulsifying oily formulations (CSNEOFs) for enhancing the oral bioavailability of olmesartan medoxomil. Initial preformulation studies, risk assessment and factor screening studies revealed selection of oleic acid, Tween 40 and Transcutol HP as the critical factors. Systematic optimization of SNEOFs was carried out employing D-optimal mixture design and evaluating them for responses viz. emulsification efficiency, globule size and in vitro drug release. The CSNEOFs were prepared from the optimized SNEOFs by adding oleylamine as cationic charge inducer. In vitro cell line studies revealed markedly better drug uptake along with safer and biocompatible nature of CSNEOFs than free drug suspension. In situ perfusion, and in vivo pharmacokinetic and pharmacodynamic studies in Wistar rats revealed significant improvement in the biopharmaceutical performance of the drug from CSNEOFs and SNEOFs vis-à-vis the marketed formulation. Successful establishment of various levels of in vitro/in vivo correlations (IVIVC) substantiated high degree of prognostic ability of in vitro dissolution conditions in predicting the in vivo performance. In a nutshell, the present studies report successful development of CSNEOFs of olmesartan medoxomil with distinctly improved biopharmaceutical performance.