Feasibility of the determination of plasma vardenafil level in rat by performance liquid chromatography-tandem mass spectrometry / 中华心血管病杂志

Objective: To develope and validate a reliable and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination of vardenafil concentration in plasma of rat. Methods: Plasma samples of normal Sprague-Dawley rats were collected. A Phenomenex Synergi Polar-RP 80A column (2.0 mm×50 mm, 4 µm) was used. Column temperature was set at 30 ℃. Mobile phase A was 0.1% formic acid in water; mobile phase B was 0.1% formic acid in acetonitrile. The flow rate was 0.4 ml/minutes. Quantitative determination was performed by electrospray ionization, operating in positive ion multiple reaction monitoring (MRM) mode. Cisapride was used as the internal standard. The feasibility of the method was evaluated by examining its specificity, linearity and quantitative range, precision and accuracy, matrix effects, and stability. Results: Under the selected chromatographic and mass spectrometry conditions, the monitoring ions of vardenafil and internal standard were mass-to-charge ratio（m/z) 489.3/151.2 and 466.4/234.2, the retention times of vardenafil and internal standard were 2.62 and 2.80 minutes, respectively, and the peak shape was satisfactory. The method has good linearity in the concentration range of 0.2-200 ng/ml. The intra-batch precision (%CV) and accuracy (%DEV) of vardenafil were 1.5%-9.7% and -6.8%-6.6%, respectively. The inter-batch precision and accuracy of vardenafil were 3.1% -8.4% and -3.7%-4.6%, respectively. In this sample processing method, the extraction recovery rate of vardenafil was obtained at range of 88.2%-104.6%, which met the requirements for the investigation of extraction recovery rate. In this sample processing method, the normalized matrix factor of each quality control concentration of vardenafil was 1.04, 0.85, and 1.04, and the coefficient of variation (%CV) was in the range of 1.7%-10.7%, which met the requirements for the investigation of matrix effects. Variations of short-term stability, long-term stability, and stability of 4 freeze-thaw cycles of vardenafil was within ±15%, and the coefficient of variation were within 5%. Conclusion: The high performance liquid chromatography-tandem mass spectrometry method established in this study is feasible for the measurement of concentration of vardenafil in rat plasma and this method has good specificity and high accuracy, and can be used to detect the concentration of vardenafil in rat plasma.

Study on the establishment of international comparable chinese hospital management survey system / 中国卫生政策研究

To understand the management level and international positioning of Chinese hospitals, we devel-oped a comprehensive survey instrument of chinese hospital management survey following the well-adapted methodolo-gy of world management survey which has been widely used internationally. The survey was conducted on 20 manage-ment practices covering four major management dimensions including operations management, performance manage-ment, target management and talent management respectively. Based on the CHMS structure and setting, the four-di-mension and twenty-item management model was analyzed with construct validity test. From the test, the middle level managers were recruited from more than 400 chinese national representative hospitals. The results showed that the chi-square/degree of freedom (CMIN/DF) is 2. 209, and RMSEA (root mean square error approximate) is 0. 039, indicating a good model fitting. The further indications of model fit such as GFI, IFI and CFI were all above 0. 9 which is the typical benchmark for model acceptance. This study provides evidence for correspondence between con-ceptual and empirical hospital management and the insight of model fitting on the current data. The results conclude that CHMS has satisfied validation in Chinese hospital management practices, and can be used as an effective sur-vey method to assess the level of Chinese hospital management and to provide a general platform for international comparison.