[Effects of sweetie juice on nifedipine pharmacokinetics in rats]

It has been reported that grapefruit juice (GJ) causes pharmacokinetic interactions with many drugs after co-ingestion, but the effects of the juice of sweetie fruit, a cross between a pomelo and a grapefruit, on the pharmacokinetics of medicines have not been clear. The present study investigated the drug interaction capability of sweetie juice (SJ). The effect of SJ on nifedipine (NFP) pharmacokinetics in rats was studied. Two milliliters of SJ, GJ, or saline was administered to the rat duodenum. After 30 min, NFP was administered intraduodenally at a dose of 3 mg/kg body weight. The NFP concentrations in the plasma samples were determined by high performance liquid chromatography (HPLC). Although GJ increased the area under the plasma concentration-time curve (AUC) of NFP (1.6-fold), SJ had no significant effect on the NFP pharmacokinetics in rats. Furthermore, concentrations of furanocoumarin derivatives in SJ were measured by HPLC equipped with a photodiode array detector, and compared with those in GJ. SJ contained lower concentrations of bergamottin (0.53 microg/ml), 6', 7'-dihydroxybergamottin (0.19 microg/ml), and bergaptol (0.2 microg/ml) than the GJ used in this study (6.3 microg/ml, 3.6 microg/ml, and 9.4 microg/ml, respectively). In conclusion, the results suggest that SJ had no effect on the NFP pharmacokinetics in rats due to low furanocoumarin concentrations in SJ.