Cationic self-nanoemulsifying formulations of tamoxifen with improved biopharmaceutical attributes and anticancer activity: Systematic development and evaluation

A cationic nanoemulsion of tamoxifen (Tmx) containing a charge inducer was developed for improving biopharmaceutical attributes and anticancer potential of the drug. The lipidic formulation constituted of corn oil, labrasol and transcutol HP and optimized using a mixture design by selecting these excipients as the independent variables. The formulation was evaluated for globule size, polydispersity index and drug release characteristics as the dependent variables. Oleylamine was incorporated into the optimized nanoemulsion for inducing a positive charge. The optimized cationic Tmx-nanoemulsion with 34%:48%:17% of the aforementioned excipients and 0.5% v/v of the charge inducer showed particle size of 138 nm and a polydispersity index 0.31, zeta potential +35.45 mV and more than 85% Tmx release in a 1 h time period. In vitro evaluation of the cytotoxicity, qualitative and quantitative uptake studies on Caco-2 and MCF-7 cells revealed satisfactory results. In vivo pharmacokinetic study in rats under fasting condition showed a significant increase in the rate and extent of drug absorption (2 to 4-folds) from the optimized cationic Tmx-nanoemulsion vis-à-vis the pure drug (p < 0.001). The results observed from the aforementioned studies construed significant augmentation in the biopharmaceutical performance and anticancer activity of the drug from the prepared cationic nanoemulsion.