title: A rapid and sensitive LC-ESI-MS/MS method for detection and quantitation of methylprednisolone and methylprednisolone acetate in rat plasma after intra-articular administration.
abstract: A rapid, sensitive and specific liquid chromatography-electrospray-tandem mass spectrometric (LC-ESI-MS/MS) method for the simultaneous detection and quantitation of methylprednisolone acetate (MPA) and methylprednisolone (MP) in rat plasma, using a triple-stage quadrupole, has been developed and validated. MP-D(2) was used as internal standard (IS) and acetonitrile was added to plasma samples for protein precipitation. After extraction with dichloromethane, the analytes were separated on a C-12 reversed-phase column by isocratic elution (6min at a flow rate 0.2mLmin(-1)) with water containing 0.01% formic acid (A) and acetonitrile (B) (50:50, v/v). Quantitation was performed in positive ion multiple reaction monitoring (MRM) mode by applying the following precursor-to-product ion transitions: MPA m/z 417-->135+161+253; MP m/z 375-->135+161+253; IS m/z 377-->135+161+253. The method, validated over the concentration range 6-600ngmL(-1), has been shown to meet the current requirements of bioananalytical validation, providing satisfactory results in terms of linearity, recovery, intra-day and inter-day precision and accuracy. The lower limit of quantitation (LLOQ) was 6ngmL(-1) for both the analytes (0.080 and 0.072pmol injected for MP and MPA, respectively). The method was successfully applied to monitor the plasma levels of MPA and MP following intra-articular (IA) injections of a low MPA (Depo-Medrol((R))) dose in rats.
authors.affiliation: Dipartimento di Scienze Farmaceutiche P. Pratesi, Universita' degli Studi di Milano, 20133 Milan, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Panusa
authors.forename: Marica
authors.initials: M
authors.lastname: Orioli
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Aldini
authors.forename: Marina
authors.initials: M
authors.lastname: Carini
mesh_terms: D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods; D007270:Injections, Intra-Articular; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000097:blood*; D000077555:Methylprednisolone Acetate; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods; D013997:Time Factors
chemical_list: D000077555:Methylprednisolone Acetate; D008775:Methylprednisolone