Effects of Polyoxyethylene Alkyl Ethers on the Intestinal Transport and Absorption of Rhodamine 123: A P-glycoprotein Substrate by In Vitro and In Vivo Studies.

We examined the effects of polyoxyethylene alkyl ethers (Brijs) on the intestinal transport and absorption of rhodamine 123, a P-glycoprotein (P-gp) substrate, by in vitro and in vivo studies. Brijs increased the absorptive transport of rhodamine 123 and decreased its secretory transport in the in vitro diffusion chamber method. However, Brijs did not change the transport of 5(6)-carboxyfluorescein, a non-P-gp substrate, indicating that the effect of Brijs on the transport of drugs was P-gp substrate-specific.