Analytical Sciences

Abstract − Analytical Sciences, 37(8), 1105 (2021).

Rapid Interference-free Analysis of β-Lapachone in Clinical Samples Using Liquid Chromatography–Mass Spectrometry for a Pharmacokinetic Study in Humans
Bo Kyung KIM,*,** Mi-Ri GWON,*,** Woo Youl KANG,* In-Kyu LEE,*** Hae Won LEE,* Sook Jin SEONG,*,** Seungil CHO,** and Young-Ran YOON*,**
*Department of Molecular Medicine, School of Medicine, Kyungpook National University and Department of Clinical Pharmacology, Kyungpook National University Hospital, Daegu, 41944, Republic of Korea
**Clinical Omics Institute, School of Medicine, Kyungpook National University, Daegu, 41944, Republic of Korea
***Department of Internal Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, 41944, Republic of Korea
A rapid analytical method developed for the analysis of β-lapachone in in vitro samples could not be directly applied to the analysis of clinical samples because of interference from unknown substances. Here, we developed and validated a rapid interference-free analytical method to accurately determine β-lapachone levels in human plasma using liquid chromatography–tandem mass spectrometry. First, we achieved the baseline-separation of β-lapachone from any interfering substances within a total run time of 4 min by adjusting the eluent strength of the mobile phase. Second, precursor-ion scanning revealed the identity of the interfering substances. Sulfonate- or glucuronide-conjugated metabolites were converted to β-lapachone in an electrospray ion source, causing interference. In a method validation study, calibration curves for β-lapachone in human plasma were linear over a concentration range from 0.5 to 200 ng/mL (r > 0.999), and the lower limit of quantification was 0.5 ng/mL. The other validation parameters, including intra- and interday accuracy and precision, were acceptable with a coefficient of variation less than 10% (n = 5). The validated analytical method was successfully applied to a pharmacokinetic study of a single, oral dose of 100 mg MB12066 (a clinical form of β-lapachone) in healthy volunteers.