Effect of the Phragmitis rhizoma Aqueous Extract on the Pharmacokinetics of Docetaxel in Rats

BACKGROUND: Traditionally, Phragmitis rhizoma has been prescribed to relive a fever, vomiting, dysuria, and constipation, and to promote secretion of fluids. In addition, recent studies have reported its efficacy as a diuretic and antiemetic. Our previous study demonstrated that the Phragmitis rhizoma aqueous extract (EPR) ameliorates docetaxel (DTX)-induced myelotoxicity. AIM AND OBJECTIVE: This study was aimed to investigate the effects of EPR on the pharmacokinetics of DTX in Sprague-Dawley rats. MATERIALS AND METHODS: The animals received an intravenous injection of DTX (5 mg/kg) with or without oral EPR (100 mg/kg) pretreatment for 1 or 6 days. The pharmacokinetics of plasma DTX was analyzed using an ultra-performance liquid chromatography-tandem mass spectrometry system, and pharmacokinetic parameters were estimated via noncompartmental analysis. RESULTS: Relative to the control group (DTX alone), EPR pretreatment did not affect significantly the overall profiles of plasma DTX levels. Consecutively pretreated EPR for 6 days slightly altered AUC(0-t) and C(max) of DTX by 122 and 145.9%, respectively, but these data did not reach the threshold of statistical significance (p > 0.05). CONCLUSION: These results indicate that DTX exposure may not be affected by EPR treatment at the dose level used in this study, suggesting that oral EPR can be used safely when taken with intravenously injected DTX. However, further studies under the stringent conditions are needed when chronic treatment of EPR and anticancer drug.