Determination of Colistin and Colistimethate Levels in Human Plasma and Urine by High-Performance Liquid Chromatography-Tandem Mass Spectrometry.
Colistin is a polypeptide antibiotic from the polymyxin E group used for the treatment of infections caused by multidrug-resistant gram-negative bacteria. The main constituents, accounting for approximately 85% of this mixture, are colistin A (polymyxin E1) and colistin B (polymyxin E2). The aim of this study was to develop and validate new and fast methods of quantification of colistin A and B and its precursors [colistin methanesulfonate sodium (CMS) A and B] by ultraperformance liquid chromatography-tandem mass spectrometry in plasma and urine with short pretreatment and run times.



Chromatography was performed on an Acquity UPLC-MS/MS system (WATERS) with a WATERS Acquity UPLC C18 column (4.6 × 150 mm, 3.5 μm particle size). The pretreatment of samples consists of precipitation and extraction into microcolumns plate and HLB 96-well plate 30 μm-30 mg (OASIS) with a Positive Pressure-96 (WATERS).



Quantification was performed using a multiple reaction monitoring of the following transitions: m/z 390.9 → 385.1 for colistin A, m/z 386.2 → 101.0 for colistin B, and m/z 602.4 → 241.1 for polymyxin B1 sulfate. In plasma and urine, calibration curves were linear from 30 to 6000 ng/mL for colistin A and from 15 to 3000 ng/mL for colistin B. With an acceptable accuracy and precision, the lower limit of quantification were set at 24.0 ng/mL and 12.0 ng/mL for colistin A and B in plasma, and at 18.0 ng/mL and 9.0 ng/mL for colistin A and B in urine.



These LC-MS/MS methods of quantification for colistin A and B and its precursors (CMS A and B) in plasma and urine are fast, simple, specific, sensitive, accurate, precise, and reliable. Furthermore, they are linear and repeatable. These procedures were successfully applied to a pharmacokinetic study of a critically ill patient suffering from ventilator-associated pneumonia, who was treated with nebulized CMS.
*Department of Pharmacology and CIC-1421, AP-HP, Pitié-Salpêtrière Hospital; †Multidisciplinary Intensive Care Unit, Department of Anesthesiology and Critical Care, Pitié-Salpêtrière hospital, Assistance Publique-Hôpitaux de Paris, UPMC Univ; and ‡Department of Pharmacology and UMR ICAN 1166, Faculty of Medicine, Sorbonne Universités, UPMC Univ Paris 06, Paris, France.
Kevin
K
Bihan
Qin
Q
Lu
Manon
M
Enjalbert
Maxime
M
Apparuit
Olivier
O
Langeron
Jean-Jacques
JJ
Rouby
Christian
C
Funck-Brentano
Noël
N
Zahr
D000900:Anti-Bacterial Agents / Q000097:blood / Q000652:urine; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003091:Colistin / Q000031:analogs & derivatives* / Q000097:blood* / Q000652:urine*; D016903:Drug Monitoring / Q000379:methods; D006801:Humans; D011113:Polymyxins / Q000097:blood / Q000652:urine; D053719:Tandem Mass Spectrometry / Q000379:methods
D000900:Anti-Bacterial Agents; D011113:Polymyxins; C004691:colistinmethanesulfonic acid; D003091:Colistin