OBJECTIVETo prepare CIT microemulsion and to investigate its properities and the absorption character in rat intestine in situ.

METHODThe optimum formulation of the blank microemulsion was selected by pseudo tertiary phase diagrams and the CIT microemulsion was prepared based on the blank microemulsion. The appearance, particle diameter distribution and Zeta potential were investigated by electron microscopy and grainsize analyzer. The entrapment efficiency was determined by sephadex column chromatography. An in situ single pass intestine perfusion method was used to investigate the intestinal absorption of CIT microemulsion. HPLC method for determination of CIT in the intestinal flux was established.

RESULTThe formulation was OP-glycerol-water-ethylis oleas (3:3:4:2). CIT microemulsion in electron microscopy was consisted of small spherical drop. The mean diameter was 61.7 nm, Zeta potential was -46.3 mV. The Entrapment efficiency was (92.1 +/- 1.74)% (n=3). Both CIT and CIT microemulsion had been absorbed in general intestinal tract,and the absorption of CIT microemulsion was significantly high compared with CIT in duodenum, colon, jejunum and ileum (P < 0.01).

CONCLUSIONThe preparation technology of CIT microemulsion was feasible,and the microemulsion system might improve the absorption of CIT in the intestinal tract.