Quantitative analysis of the novel depsipeptide anticancer drug Kahalalide F in human plasma by high-performance liquid chromatography under basic conditions coupled to electrospray ionization tandem mass spectrometry

• Published in: Journal of mass spectrometry. Vol. 37; no. 9; pp. 992 - 1000
• Main Authors: Stokvis, E., Rosing, H., López-Lázaro, L., Rodriguez, I., Jimeno, J. M., Supko, J. G., Schellens, J. H. M., Beijnen, J. H.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-09-2002; Wiley
• Subjects: Analysis; Antineoplastic Agents - blood; Antineoplastic Agents - pharmacokinetics; Area Under Curve; bioanalysis; Biological and medical sciences; Calibration; Chromatography, High Pressure Liquid; Depsipeptides; Drug Stability; General pharmacology; Humans; Kahalalide F; liquid chromatography/mass spectrometry; Medical sciences; peptide; Peptides - blood; Peptides - pharmacokinetics; Pharmacology. Drug treatments; Quality Control; Reference Standards; Reproducibility of Results; Spectrometry, Mass, Electrospray Ionization; trifluoroacetic acid; Antineoplastic agent; Human; Solid phase extraction; Biological fluid; Chemical analysis; Oligopeptides; Coupled method; Cyclic peptides; HPLC chromatography; Fragmentation pattern; Electrospray; Blood; Blood plasma; Sample preparation; Depsipeptide; Mass spectrometry MS/MS; Quantitative analysis
• ISSN: 1076-5174; 1096-9888
• DOI: 10.1002/jms.362

Kahalalide F (KF) is a novel cyclic depsipeptide anticancer drug, which has shown anticancer activity both in vitro and in vivo especially against human prostate cancer cell lines. To characterize the pharmacokinetics of KF during a phase I clinical trial in patients with androgen refractory prostate cancer, a method was developed and validated for the quantitative analysis of KF in human plasma using high‐performance liquid chromatography (HPLC) coupled to positive electrospray ionization tandem mass spectrometry (ESI‐MS/MS). Microbore reversed‐phase liquid chromatography (LC) performed with mobile phases containing trifluoroacetic acid, an additive commonly used for separating peptides, resulted in substantial suppression of the signal for KF on ESI‐MS/MS. An alternative approach employing a basic mobile phase provided an excellent response for KF when detected in the positive ion mode. Plasma samples were prepared for LC MS/MS by solid‐phase extraction on C18 cartridges. The LC separation was performed on a Zorbax Extend C18 column (150 × 2.1 mm i.d., particle size 5 µm) with acetonitrile –10 mM aqueous ammonia (85 : 15, v/v) as the mobile phase, at a flow‐rate of 0.20 ml min−1. A butyric acid analogue of KF was used as the internal standard. The lower limit of quantitation (LLQ) using a 500 µl sample volume was 1 ng ml−1 and the linear dynamic range extended to 1000 ng ml−1. The inter‐assay accuracy of the assay was −15.1% at the LLQ and between −2.68 and −9.05% for quality control solutions ranging in concentration from 2.24 to 715 ng ml−1. The inter‐assay precision was 9.91% or better at these concentrations. The analyte was stable in plasma under all relevant conditions evaluated and for a period of 16 h after reconstituting plasma extracts for LC analysis at ambient temperature. Copyright © 2002 John Wiley & Sons, Ltd.