title: Sensitive and specific quantification of sirolimus (rapamycin) and its metabolites in blood of kidney graft recipients by HPLC/electrospray-mass spectrometry.
abstract: Sirolimus (rapamycin) has a macrolide structure and is under clinical investigation as an immunosuppressant after organ transplantation. An HPLC/mass spectrometry assay to quantify sirolimus in blood was developed. 28-O-Acetyl sirolimus was used as internal standard. Blood samples were extracted with C18 columns. The extracts were injected into an HPLC system and isocratically eluted with methanol/1% formic acid (90/10 by vol) from a 150 X 4 mm C18 analytical column. The HPLC system was connected to a triple-stage quadrupole mass spectrometer with an electrospray interface and positive ions were detected. The limit of quantification in 1 mL of blood was 0.25 microgram/L and the calibration curve in blood was linear up to 250 microgram/L. The recovery from blood was 88 +/- 26% and interassay variation at 1 microgram/L was 19% and at 15 microgram/L 9.3%. Hydroxy, dihydroxy, demethyl, and didemethyl sirolimus as well as sirolimus were detected in blood of kidney graft patients.
authors.affiliation: Institut für Allgemeine Pharmakologie, Medizinische Hochschule Hannover, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Streit
authors.forename: U
authors.initials: U
authors.lastname: Christians
authors.forename: H M
authors.initials: HM
authors.lastname: Schiebel
authors.forename: K L
authors.initials: KL
authors.lastname: Napoli
authors.forename: L
authors.initials: L
authors.lastname: Ernst
authors.forename: A
authors.initials: A
authors.lastname: Linck
authors.forename: B D
authors.initials: BD
authors.lastname: Kahan
authors.forename: K F
authors.initials: KF
authors.lastname: Sewing
mesh_terms: D000089:Acetic Anhydrides; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood*; D016030:Kidney Transplantation; D013058:Mass Spectrometry / Q000379:methods; D015394:Molecular Structure; D011090:Polyenes / Q000097:blood*; D012680:Sensitivity and Specificity; D020123:Sirolimus
chemical_list: D000089:Acetic Anhydrides; D007166:Immunosuppressive Agents; D011090:Polyenes; C031800:acetic anhydride; D020123:Sirolimus