PAMAM G4.5 dendrimers for targeted delivery of ferulic acid and paclitaxel to overcome P‐glycoprotein‐mediated multidrug resistance

In this study, we prepared ferulic acid (FA) and paclitaxel (PTX) co‐loaded polyamidoamine (PAMAM) dendrimers conjugated with arginyl–glycyl–aspartic acid (RGD) to overcome P‐glycoprotein (P‐gp)‐mediated multidrug resistance (MDR). FA was released in greater extent (80%) from the outer layer of the dendrimers compared with PTX (70%) from the interior of the dendrimers. FA improved intracellular availability of PTX via P‐gp modulation in drug‐resistant cells. In vitro drug uptake data show higher PTX delivery with RGD–PAMAM–FP than with PAMAM–FP in drug resistant KB CH‐R 8‐5 cell lines. This indicates that RGD facilitates intracellular PTX accumulation through active targeting in multidrug‐resistant KB CH‐R 8‐5 cells. The terminal deoxynucleotidyl transferase 2ʹ‐deoxyuridine 5ʹ‐triphosphate nick‐end labeling assay data and membrane potential analysis in mitochondria confirm the enhanced anticancer potential of RGD–PAMAM–FP nanoaggregates in drug‐resistant cells. We also confirmed by the increased protein levels of proapoptotic factors such as caspase 3, caspase 9, p53, and Bax after treatment with RGD–PAMAM–FP nanoaggregates and also downregulates antiapoptotic factors. Hence, FA–PTX co‐loaded, RGD‐functionalized PAMAM G4.5 dendrimers may be considered as an effective therapeutic strategy to induce apoptosis in P‐gp‐overexpressing, multidrug‐resistant cells. RGD–PAMAM–FP transports paclitaxel and ferulic acid through RGD receptor mediated endocytosis. Ferulic acid downregulates P‐gp expression and attenuates its transport function, thereby increases intracellular Paclitaxel concentration.