Simultaneous determination of bendamustine and its active metabolite, gamma-hydroxy-bendamustine in human plasma and urine using HPLC-fluorescence detector: Application to a pharmacokinetic study in Chinese cancer patients

A simple, sensitive and cost-effective assay based on reversed phase high performance liquid chromatography (RP-HPLC) with isocratic mode for simultaneous determination of bendamustine (BM) and its active metabolite, gamma-hydroxy-bendamustine (γ-OH-BM) in human plasma and urine was developed and validated. Sample preparation involved protein precipitation by 10% perchloric acid-methanol solution. The peaks were recorded by using fluorescence detector (excitation wavelength 328 nm and emission wavelength 420 nm). The calibration curves were linear over concentration ranges of 8.192–10,000 ng mL−1 and 5–1000 ng mL−1 for BM in human plasma and urine as well as 10–1000 ng mL−1 and 5–1000 ng mL−1 for γ-OH-BM in human plasma and urine, respectively. Intra- and inter-run precisions of BM and γ-OH-BM were less than 15% and the bias were within ±15% for both plasma and urine. This validated method was successfully applied to a pharmacokinetic study enrolling 10 Chinese patients with indolent B-cell non-Hodgkin lymphoma and chronic lymphocytic leukemia administered a single intravenous infusion of 100 mg m2 bendamustine hydrochloride.