title: Use of a small particle solid-core packing for improved efficiency and rapid measurement of sirolimus and everolimus by LC-MS/MS.
abstract: Measurement of whole blood sirolimus and everolimus is required in order to optimize patient treatment following solid organ transplant. Assay by LC-MS/MS is increasingly preferred; however efficient use of the instrument and short turnaround times are crucial. Use of a 1.6 µm solid-core packing HPLC column (Cortecs) gave significant increases in efficiency, sensitivity and throughput compared with an existing method, following simple protein precipitation of small-volume (20 μL) whole blood samples. Sirolimus, everolimus and the stable isotopic internal standard ((13) C2 D4 - everolimus) eluted at around 0.8 min, and total analytical run time was 2.2 min, saving almost 4 min per sample compared with an existing method. Within-assay imprecision (CV) was 3.3-8.5%, and between-assay imprecision was 2.2-10.8%. Retrospective assay of external quality assurance samples and comparison of patient samples assayed in parallel showed only small differences (between +6.8 and -1.9%) in results using the Cortecs column when compared with the existing method. No significant interferences or ion suppression were observed. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Immunosuppressive Drug Monitoring Service, Institute of Liver Studies, King's College Hospital Foundation Trust, London, SE5 9RS, UK.
authors.forename: Phillip
authors.initials: P
authors.lastname: Morgan
authors.affiliation: Immunosuppressive Drug Monitoring Service, Institute of Liver Studies, King's College Hospital Foundation Trust, London, SE5 9RS, UK.
authors.forename: Magnus
authors.initials: M
authors.lastname: Nwafor
authors.affiliation: Immunosuppressive Drug Monitoring Service, Institute of Liver Studies, King's College Hospital Foundation Trust, London, SE5 9RS, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Tredger
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D000068338:Everolimus / Q000097:blood*; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood*; D020123:Sirolimus / Q000097:blood*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D007166:Immunosuppressive Agents; D000068338:Everolimus; D020123:Sirolimus
keywords: Cortecs; LC-MS/MS; everolimus; sirolimus; solid-core