P-gp/BCRP-IN-1 (compound 19) is a potential, relatively safe, orally active and efficient efflux transporter ( P-gp and BCRP ) inhibitor. P-gp/BCRP-IN-1 exerts resistance reversal by inhibiting the efflux function of P-gp and BCRP. P-gp/BCRP-IN-1 can overcome the resistance and improve the oral bioavailability of PTX (Paclitaxel).