A simple, specific, and economical LC–MS/MS method was investigated for the screening of 43 prescribed antihy-pertensive and related drugs in human urine. The urine samples were simply prepared by diluting and mixing with internal stan-dard before directly introduced to the LC-MS/MS system, which is fast, straightforward, and cost-effective. Fractional factorial, Box-Behnken, and I-optimal design were applied to screen and optimize the mass spectrometric and chromatographic factors. The analysis was carried out on a triple quadrupole mass spectrometer system utilizing multiple reaction monitoring with posi-tive and negative electrospray ionization method. Chromatographic separation was performed on a Thermo Scientific Accucore RP-MS column (50 × 3.0 mm ID., 2.6 µm) using two separate gradient elution programs established with the same mobile phases. Chromatographic separation was performed within 12 min. The optimal method was validated based on FDA guideline. The results indicated that the assay was specific, reproducible, and sensitive with the limit of detection from 0.1 to 50.0 µg/L. The method was linear for all analytes with coefficient of determination ranging from 0.9870 to 0.9981. The intra-assay preci-sion was from 1.44 to 19.87% and the inter-assay precision was between 2.69 and 18.54% with the recovery rate ranges from 84.54 to 119.78% for all drugs measured. All analytes in urine samples were stable for 24 h at 25 o C, and for 2 weeks at -60 o C. The developed method improves on currently existing methods by including larger number of cardiovascular medications and better sensitivity of 12 analytes.
An innovative, simple, and rapid assay method based on liquid chromatography coupled with tandem mass spec- trometry (LC-MS/MS) was developed and validated for the simultaneous determination of eight statin drugs in human urine. A simple sample clean-up procedure using the “dilute and shoot” (DAS) approach enabled a fast and reliable analysis. The influ- ence of the dilution factor was investigated to ensure detectability and reduce the matrix effect. Chromatographic separation was performed on a Phenomenex Kinetex C18 column (50 × 3.0 mm i.d., 2.6 µm) using an elution gradient of mobile phase A com- posed of 0.1% acetic acid, and mobile phase B composed of acetonitrile, at a flow rate of 0.35 mL/min. Quantitation was per- formed on a triple quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode using electrospray ionization in positive ion mode. The total chromatographic run time was 15 min. The method was validated for selectivity, sen- sitivity, recovery, linearity, accuracy, precision, and stability. The present method was successfully applied to the analysis of Rosuvastatin in urine samples after oral administration to healthy human subjects.