Objective:To determine the oil/water partition coefficient of homoplantaginin and to investigate its absorption characteristics in various intestinal segments in rats. Method: A HPLC(shake flask method) was established to determine n-octanol/water partition coefficient of homoplantaginin in n-octanol(water and n-octanol) different pH solution; the intestinal absorption characteristics were detected by the in situ perfused rat intestinal model

the concentration of phenol red was determined by UV method while those of homoplantaginin was analysed by HPLC method. Result: The allocation ratio of homoplantaginin in octanol/water system was 18.07 (lgP=1.26) and the PH of buffer solution had no influence on its distribution coefficient. The Ka and Peff of homoplantaginin showed jejunum>duodenum>ileum>colon in four regions of intestine. The values of Ka and Peff of different drug concentrations had no significant influence

furthermore

the values of Ka and Peff of different intestines showed to be jejunum>duodenum>ileum>colon. Conclusion: Homoplantaginin can be absorbed in whole intestinal segment

the absorption mechanism may be related to passive diffusion.