Pharmacokinetic study of eplerenone in rats after long-term coadministration with buckwheat tea

The aim of this study was to investigate the effect of long-term intake of Tartary buckwheat tea on the pharmacokinetics (PK) of eplerenone in rats. A validated high-performance liquid chromatography-mass spectrometry (HPLC-MS) method was established to determine the eplerenone in plasma, and the portal vein absorption model was applied to conduct the pharmacokinetic study. Two groups of animals—buckwheat tea group and control group—were involved in this study. Plasma samples were obtained at different time points after administration, and were separated on Shimadzu HPLC-MS 2020 instruments. The method showed good linearity (r = 0.9988) over a wide dynamic range (0.20–50 μg/mL). Within- and between-batch precisions ranged from 2.13% to 7.90%. The extraction recovery rates ranged from 91.96% to 94.96%. The data showed that in the Tartarian buckwheat group the area under the curve and maximum concentration of eplerenone were reduced compared with those of the blank group (p < 0.01), but the time to reach peak concentrations of eplerenone (p < 0.01) was prolonged. The results suggested that long-term consumption of Tartary buckwheat tea might induce the activities of the hepatic drug metabolizing enzyme, which can accelerate the metabolism of eplerenone. According to the results, the dosage of eplerenone should be adjusted in hypertension treatment trials when administered with Tartary buckwheat or Tartary buckwheat-containing dietary supplements to avoid potential drug interactions.