John Wadsworth (Presenter)
Royal Liverpool University Hospital
Bio: A recently qualified clinical biochemist. Doctoral research was undertaken at the University of Edinburgh investigating the role of sphingolipids in diabetes. I have spent the last three years completing my clinical training at the Royal Liverpool Hospital but I have just taken up a new clinical biochemistry position back home in the Glasgow Royal Infirmary.
Authorship: John M. Wadsworth(1), Anna M.Milan(1), James Anson(2), Andrew S. Davison(1)
Departments of 1) Clinical Biochemistry and Metabolic Medicine and 2) Infection and Immunity, Liverpool Clinical Laboratories, Royal Liverpool Hospital, Prescot Street, Liverpool, L7 8XP
| Short Abstract In response to recent clinical guidance advocating the need for antifungal therapeutic drug monitoring and the increased use of antifungal therapies both prophylactically as well as for active treatment has resulted in an increase in requesting. In response to this we have validated a simple and robust method for the determination of voriconazole, posaconazole and itraconazole concentration in serum using LC-MS/MS. This new assay will result in a greatly improved sample turnaround time and will therefore vastly increase the clinical utility of azole antifungal drug monitoring. |
Long Abstract
Introduction: Azole based antifungals are the first line therapy for some of the most common mycoses and are now also being used prophylactically to protect immunocompromised patients. However due to variability in both their metabolism and bioavailability, therapeutic drug monitoring is essential to avoid toxicity but still gain maximum efficacy.
Methods: Following protein precipitation with acetonitrile, 20 µL of extract was injected onto a 2.1x50mm Waters Atlantis C18 3 µm column. Detection was via a Waters Quattro Premier tandem mass spectrometer operating in ESI positive mode. Multiple reaction monitoring (MRM) detected two product ions for each compound and one for each isotopically labelled internal standard. Ion suppression, linearity, stability, matrix effects, recovery, imprecision, lower limits of measuring interval (LLMI)and detection were all assessed.
Results: Optimal chromographic separation was achieved using gradient elution over 8 mins. Voriconazole, posaconazole and itraconazole eluted at 1.71, 2.73 and 3.41 minutes, respectively. The LLMI for all three compounds was 0.1 mg/L. The assay was linear to 10 mg/L for voriconazole (R2 = 0.9958) and 5 mg/L for posaconazole (R2 = 0.9901) and itraconazole (R2 = 0.9916). The assay was both highly accurate and precise with % bias of only -4.7%, 0.5% and 1.1% and an intra-assay precision (CV %) of 1.6%, 2.5% and 1.9% for voriconazole, posaconazole and itraconazole respectively across the linear range.
Conclusion: A simple and robust method has been validated for azole antifungal therapeutic drug monitoring. This new assay will result in a greatly improved sample turnaround time and will therefore vastly increase the clinical utility of azole antifungal drug monitoring.
References & Acknowledgements:
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