A highly sensitive assay for ritodrine in human serum by hydrophilic interaction chromatography-tandem mass spectrometry.
We developed a sensitive assay for ritodrine (RTD), a beta2-adrenergic agonist, in human serum. This method was based upon the selective and sensitive technique by a tandem mass spectrometry (MS/MS) using a hydrophilic interaction chromatography (HILIC) technique. This method involved a mixed-mode cation-exchange solid-phase extraction of RTD and isoxsuprine, the internal standard (IS), from serum with Waters Oasis MCX cartridges. The detection was made using a Micromass Quattromicro API LC-MS/MS system with electrospray ionization source in positive ion mode. The separation of the analytes was achieved within 4 min on a silica column with a mobile phase of ammonium acetate (10 mM, pH 4.5) and acetonitrile (10:90, v/v). Multiple reaction monitoring was utilized by monitoring 288.2-->121.1 for RTD, 302.2-->107.0 for IS. The calibration curve for RTD was linear over a range of 0.5-1000 ng/mL. When 50 microL serum was used for extraction, the lower limit of quantification was 0.39 ng/mL (97.5 fg on-column). The percent coefficient of validation for accuracy and precision (inter- and intra-day) was less than 9.8% and the recovery was ranged from 83.5 to 94.7% for RTD. This method enabled us to successfully determine RTD in maternal and fetal sera.
Laboratory of Pharmaceutics, Gifu Pharmaceutical University, 5-6-1, Mitahora-higashi, Gifu 502-8585, Japan.
Tomofumi
T
Ohmori
Mitsuhiro
M
Nakamura
Shin
S
Tada
Tadashi
T
Sugiyama
Yoshinori
Y
Itoh
Yasuhiro
Y
Udagawa
Kazuyuki
K
Hirano
D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D015394:Molecular Structure; D015203:Reproducibility of Results; D012312:Ritodrine / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry / Q000379:methods*
D012312:Ritodrine