Enhanced permeability of etoposide across everted sacs of rat small intestine by vitamin E-TPGS

ABSTRACT

Etoposide, a widely used anticancer drug, exhibits low and variable oral bioavailability mainly because of being substrate for the efflux transporter, P-glycoprotein [P-gp]. Therefore, the present study was aimed to investigate the effect of D-alpha-tocopherol polyethylene glycol 1000 succinate [TPGS] and PEG 400 as P-gp inhibitors on the intestinal absorption of etoposide. Everted sacs of rat small intestine were incubated in Krebs buffer solution which contained etoposide in the absence or presence of various concentrations of TPGS or PEG 400. The effect of verapamil as a known P-gp inhibitor on the absorption of drug was also studied