title: Determination of rapamycin: quantification of the sodiated species by an ion trap mass spectrometer as an alternative to the ammoniated complex analysis by triple quadrupole.
abstract: Rapamycin is a potent immunosuppressive drug capable of significantly reducing acute graft rejection in kidney, liver and heart transplant patients. Its immunosuppressive activity and adverse effects have been related to rapamycin concentration, and therapeutic drug monitoring of the drug is deemed appropriate. This work was aimed at developing a new quantification method based on the isolation of the [M+Na]+ ion as precursor and its further fragmentation through an ion trap mass spectrometer equipped with an electrospray ionization source. A limit of detection (LOD) of 0.7 ng/mL was obtained, while the lower limit of quantification (LLOQ) was 2.4 ng/mL. The accuracy and reproducibility of the responses were evaluated and compared with results obtained when the [M+NH4]+ ion was chosen as the precursor in a triple quadrupole mass spectrometer. In this case the LOD was 0.5 ng/mL and the LLOQ 1.7 ng/mL. Data showed that it would be possible to use the quantification of the sodiated species for the routine determination of rapamycin, as an alternative to the commonly adopted method based on the ammoniated complex.
authors.affiliation: Dipartimento di Medicina Pubblica e Sicurezza Sociale, Università di Napoli Federico II, Via S. Pansini 5, I-80131 Napoli, Italy. maria.pieri@unina2.it
authors.forename: Maria
authors.initials: M
authors.lastname: Pieri
authors.forename: Nadia
authors.initials: N
authors.lastname: Miraglia
authors.forename: Loredana
authors.initials: L
authors.lastname: Castiglia
authors.forename: Giuliana
authors.initials: G
authors.lastname: Genovese
authors.forename: Pascale
authors.initials: P
authors.lastname: Basilicata
authors.forename: Angela
authors.initials: A
authors.lastname: Simonelli
authors.forename: Antonio
authors.initials: A
authors.lastname: Acampora
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D002853:Chromatography, Liquid; D016903:Drug Monitoring / Q000379:methods*; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood* / Q000737:chemistry; D015203:Reproducibility of Results; D020123:Sirolimus / Q000097:blood* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D007166:Immunosuppressive Agents; D000641:Ammonia; D020123:Sirolimus