Ultra-performance liquid chromatography/tandem mass spectrometric determination of diastereomers of SCH 503034 in monkey plasma

This paper describes the development and qualification of a fast, sensitive and specific ultra-performance liquid chromatography/tandem mass spectrometric (UPLC/MS/MS) method for the determination of diastereomers of SCH 503034 in monkey plasma. The analytical method involves direct protein precipitation with a mixture of methanol/acetonitrile (10/90) containing an internal standard, followed by separation of the stereoisomers on an Acquity UPLC™ C18 column and detected by selected reaction monitoring (SRM) in positive ionization mode using atmospheric pressure chemical ionization (APCI). The effects of ion-pairing agents on separation and ionization efficiency were investigated. The two diastereomers were well separated (R = 1.3) with a runtime of 5 min under an isocratic condition. The method was qualified. The linear concentration range was 1–2500 ng/ml for the both stereoisomers. Inter-assay mean bias and relative standard deviation (R.S.D.) were in the range of −1.2% to 3.6% and 2.8–10%, respectively. Intra-assay mean bias and R.S.D. were in the range of −1.3% to 5.5% and 2.3–7.8%, respectively. Recoveries of the stereoisomers at concentration levels of 2.5, 50 and 1000 ng/ml were 87.2–90.0%, 89.1–90.4% and 92.3–94.3%, respectively. The LLOQ for this assay was 1 ng/ml. No matrix interferences were observed in six different sources of blank monkey plasma.