New taxanes as highly efficient reversal agents for multi-drug resistance in cancer cells

New non-cytotoxic taxanes synthesized from 10-deacetylbaccatin III and special hydrophobic acylating agents show remarkable MDR reversal activity ( 99.8%) against drug-resistant human breast cancer cells when co-administered with paclitaxel or doxorubicin. This activity is ascribed to the highly efficient blocking of P-glycoprotein efflux by these new taxanes.