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Updated: Mar 30, 2026
Multiplex Therapeutic Drug Monitoring by Isotope-dilution HPLC-MS/MS of Antibiotics in Critical Illnesses
Published on: August 30, 2018
Quantification of co-trimoxazole in serum and plasma using MS/MS
Jacob A Dijkstra1, Noor Si Alsaad1, Kai van Hateren1
1University of Groningen, University Medical Center Groningen, Department of Clinical Pharmacy & Pharmacology, Groningen, The Netherlands.
Background:
Co-trimoxazole is frequently used in the prophylaxis and treatment of Pneumocystis carinii pneumonia. High plasma concentrations of sulfamethoxazole or trimethoprim are correlated with toxicity. There is, however, a large variation in PK observed which can lead to underexposure or toxicity.
Results:
We developed a novel LC-MS/MS method to analyze the components of co-trimoxazole, trimethoprim and sulfamethoxazole and its metabolite sulfamethoxazole-N-acetyl. This new method is expeditious due to its limited sample preprocessing and a relatively short run-time of only 3 min.
Conclusion:
This new method met the US FDA requirements on linearity, selectivity, precision, accuracy, matrix effects, recovery and stability and is suitable for routine analysis and future prospective studies.
