OBJECTIVETo determine the O/W partition coefficient of geniposide in fructus gardeniae extract and investigate the absortion kinetics of geniposide in whole small intestine and different intestinal segments of rats.

METHODThe shake-flask method was employed to determine the O/W partition coefficient of geniposide; an in situ intestinal perfusion model was employed to investigate the absorptive kinetics of geniposide.

RESULTThe partition coefficient (P) of geniposide was 0.1077, logP was -0.9678; the absorptive rate constants (K) of geniposide at the concentration of 0.078, 0.311, 0.780 g x L(-1) were (0.130 +/- 0.007), (0.056 +/- 0.003), (0.031 +/- 0.006) h, respectively. The K of geniposide were (0.019 +/- 0.003), (0.015 +/- 0.002), (0.012 +/- 0.002) h at duodenum, jejunum, ileum, respectively.

CONCLUSIONAccording to the P and the logP, it could be indicated that the absorption of geniposide at small intestine was poor absorption; The absorption rate was increased with the decrease of the extract concentration; Their absorption was first-order process besides the passive diffusion mechanism, and facilitated diffusion and active transport may also take part in the transport process. Geniposide was absorbed at all smallintestinal segments of rats, but the duodenal absorption ratewas higher more than other section.