Quantitation of cyclosporin A in whole blood by liquid chromatography/stable isotope dilution electrospray ionization mass spectrometry

✍ Scribed by F. Magni; S. Pereira; M. Leoni; G. Grisenti; M. Galli Kienle

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 159 KB
• Volume: 36
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.169

✦ Synopsis

Abstract

Therapy with cyclosporin A (CsA) for immunosuppression after organ transplantation requires monitoring of its levels in blood owing to the narrow therapeutic index of the drug and to the high inter‐individual variability of the drug absorption and metabolism. We describe the preparation of CsA labelled with stable isotopes (^13^C and ^2^H) with an isotopic enrichment of about 99% using labelled glucose and its use as internal standard for quantification of CsA blood levels by isotope dilution/electrospray ionization mass spectrometry. The method was found to be linear in the tested range (1–1000 ng) with and without the matrix. The accuracy of the bracketting calibration curves prepared using 100 ng ml^−1^ labelled CsA was within ±1.7% (bias). The results confirmed the usefulness of the procedure as a reference method for the external quality assessment of the field methods for the evaluation of CsA blood concentration, the imprecision (relative standard deviation) and accuracy (bias) being <2%. Copyright © 2001 John Wiley & Sons, Ltd.