ABSTRACT
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.
Subject(s)
Animals , Rats , Chromatography, Liquid , Feasibility Studies , Rats, Sprague-Dawley , Reproducibility of Results , Sensitivity and Specificity , Tandem Mass Spectrometry , Vardenafil DihydrochlorideABSTRACT
Objective To investigate the effect of hand robot-assisted training based on motor imagery on upper limb function of stroke patients.Methods From November, 2016 to May, 2018, 55 hemiplegic patients with upper limb dysfunction were randomly assigned to control group (n = 25) and experimental group (n = 30). The control group received routine hand motor training, while the experimental group received hand robot-assisted training, for four weeks. They were assessed with simplified Fugl-Meyer Assessment-Upper Extremity (FMA-UE), Wolf Motor Function Test (WMFT) and Modified Barthel Index (MBI) before treatment (t0), one week of treatment (t1), immediately after treatment (t2) and 2 months after treatment (t3).Results The score of WMFT improved in the experimental group at t1 (P ＜ 0.05), with no significant difference between groups (Z =-0.901, P＞ 0.05). The scores of FMA, WMFT and MBI improved in both groups at t2 and t3 (P ＜ 0.05), and the scores of FMA and MBI improved more in the experimental group than in the control group (Z＞-2.073, t＞ 2.034, P ＜ 0.05).Conclusion Hand robot-assisted training based on motor imagery can promote recovery of upper limb function in stroke patients more effective than routine hand function training.