Quantitative analysis of colistin A and colistin B in plasma and culture medium using a simple precipitation step followed by LC/MS/MS

• Published in: Journal of pharmaceutical and biomedical analysis 2009-04, Vol.49 (3), p.760-767
• Main Authors: Jansson, Britt, Karvanen, Matti, Cars, Otto, Plachouras, Diamantis, Friberg, Lena E.
• Format: Article
• Language: English
• Subjects: Analysis; Analytical, structural and metabolic biochemistry; Anti-Bacterial Agents - analysis; Anti-Bacterial Agents - blood; Biological and medical sciences; Chromatography, High Pressure Liquid; CMS; Colistin; Colistin - analysis; Colistin - blood; Culture Media - analysis; Culture medium; FARMACI; Freezing; Fundamental and applied biological sciences. Psychology; General pharmacology; Humans; Hydrolysis; LC/MS/MS; Mass Spectrometry; Medical sciences; MEDICIN; MEDICINE; Particle Size; Pharmacology. Drug treatments; PHARMACY; Plasma stability; Quality Control; Reference Standards; Reproducibility of Results; Solutions; Specimen Handling; Spectrophotometry, Ultraviolet
• ISSN: 0731-7085; 1873-264X; 1873-264X
• DOI: 10.1016/j.jpba.2008.12.016

An analytical method for quantitation of colistin A and colistin B in plasma and culture medium is described. After protein precipitation with acetonitrile (ACN) containing 0.1% trifluoroacetic acid (TFA), the supernatants were diluted with 0.03% TFA. The compounds were separated on an Ultrasphere C18 column, 4.6mm×250mm, 5μm particle size with a mobile phase consisting of 25% ACN in 0.03% TFA and detected with tandem mass spectrometry. The instrument was operating in ESI negative ion mode and the precursor–product ion pairs were m/z 1167.7→1079.6 for colistin A and m/z 1153.7→1065.6 for colistin B. The lower limit of quantification (LLOQ) for 100μL plasma was 19.4 and 10.5ng/mL for colistin A and B, respectively, with CV