Multifunctional quercetin conjugated chitosan nano-micelles with P-gp inhibition and permeation enhancement of anticancer drug.

In this study, quercetin-chitosan conjugate (QT-CS) was synthesized for oral delivery of doxorubicin (DOX) to improve its oral bioavailability by increasing its water solubility, opening tight junction and bypassing the P-glycoprotein (P-gp). The prepared QT-CS self-assembled into micelles which could encapsulate DOX with high encapsulation rate, small particle size (136.9 nm) and strong zeta potential (+16.2 mV). QT-CS-DOX micelles displayed sustained-release profile in gastrointestinal simulation fluid (pH 1.2/pH 7.4). QT-CS micelles could promote cellular uptake of doxorubicin, which was 2.2 folds higher than that of free doxorubicin. The trans epithelial electrical resistance (TEER) value of Caco-2 monolayer cells was significantly reduced (about 57%) by drug loaded QT-CS micelles, leading to a high apparent permeability coefficient (P) of doxorubicin, which was 10.17 folds higher than that of free doxorubicin. Above results indicate that QT-CS micelles are promising vehicles for the oral delivery of insoluble anticancer drugs.