To study the in vivo intestinal absorption kinetics of phloridzin in rats. The absorption of phloridzin in the small intestines and colon of rats was investigated using an in vivo single-pass perfusion method and the drug concentration was measured by HPLC. The effects on intestinal absorption of different drug concentration and P-glycoprotein (P-gp) inhibitor were conducted. The results showed that the phloridzin could be absorbed in whole intestine, but more fully in the jejunum and colon segment,poorly absorbed in the duodenum and ileum. The absorption rate constant (Ka) and the apparent absorption coefficient（Papp）of phloridzin decreased following the sequence of jejunum> colon > duodenum > ileum. Absorption parameters of phloridzin had no significant difference at different concentration (5.14, 10.28, 20.56 mg•L⁻¹) . The saturate phenomena was not observed under the test range of drug concentration, and the absorption mechanism may be the passive diffusion transport.There had a significant difference in Ka and Papp values between P-gp inhibitor and no P-gp inhibitor groups. Phloridzin may be the substrate of P-gp.
Keywords: P-gp; a single-pass perfusion method; in vivo intestinal absorption; phloridzin.
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