Chitosan Encapsulation Enhances the Bioavailability and Tissue Retention of Curcumin and Improves its Efficacy in Preventing B[a]P-induced Lung Carcinogenesis.

The rate of lung cancer incidence is alarmingly mounting, despite the decline of smoking and tobacco consumption. Recent reports indicate a very high correlation between the growing fast food culture and lung cancer incidence. Benzo[a]pyrene is a potent carcinogen abundantly present in grilled and deep fried food and in tobacco smoke. Our previous studies have proved the efficacy of curcumin in curbing B[a]P-induced lung carcinogenesis. However, the poor pharmacokinetic profile of the compound considerably hampers its potential as an effective chemopreventive. The current study was intended to evaluate whether encapsulation of curcumin in chitosan nanoparticles can improve the cell uptake and prolong the tissue retention of curcumin yielding better chemoprevention. The chitosan nanocurcumin particles exhibited a size of 170-200nm in TEM. In vitro drug release studies showed sustained release of curcumin over a period of ~ 180h and excellent intracellular uptake and cytotoxicity in lung cancer cells. Bioavailability studies using healthy Swiss albino mice demonstrated drastic enhancement in lung localization of chitosan nanocurcumin compared to free curcumin. Toxicological evaluation using chronic toxicity model in Swiss albino mice confirmed the pharmacological safety of the formulation. Moreover, the formulation, even at a dose equivalent to one fourth that of free curcumin, exhibits better efficacy in reducing tumor incidence and multiplicity than free curcumin, thereby hampering development of B[a]P-induced lung adenocarcinomas in Swiss albino mice. Hence our study underscores the supremacy of the formulation over free curcumin and establishes it as a potential chemopreventive and oral supplement against environmental carcinogenesis.