Correlativity Between Solubility O/W Partition Coefficients of Berbenine Hydrochloride and Intestinal Absorption in Rats in Situ

OBJECTIVE To determine the equilibrium solubility and the partition coefficient of Berbenine Hydrochloride (BH) and to evaluate its intestinal absorption characteristic. METHODS The solubility and partition coefficient of BH were measured by shaking flask-UV spectrophotometry．The absorptions of three concentrations(50, 100, 150 μg·mL^-1) of BH in different intestinal segments were studied by phenol red assay and gravimetry. The concentrations of BH and phenol red were determined by HPLC. RESULTS The solubility of BH was increased with the pH increase of the buffer solution，and oil-water partition coefficient was decreased with increasing the pH of the buffer solution. Phenol red assay was better to reduce experimental error than gravimetry. There was positive correlation between the Permeability coefficient(P_eff) of each intestine and concentrations of BH, and it has obvious difference(P<0.05) between the high concentration and low concentration. BH was well absorbed in jejunum at high and middle concentration, however, well absorption was observed in duodenum at low concentration. CONCLUSION In the experimental range, results of partition cofficients was in good accordance with predictive ones. BH was well absorbed at upper intestine than lower intestine over the concentration range. Extension of BH absorption time at upper intestine, could improve bioavailability.