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Objective To establish a UPLC-MS/MS method for the determination of dexmedetomidine in human plasma and investigate the effect of obstructive jaundice on pharmacokinetics of dexmedetomidine in vivo. Methods Samples were obtained by liquid-liquid extraction. Agilent Eclipse Plus C18 column was used for chromatograph with methanol and 0.1% formic acid-water solution as mobile phase. Flow rate was 0.2 ml/min. The column temperature was 35 ℃, and the MS detection was selected in MRM mode. Results The calibration curves of dexmedetomidine showed good linearity in the ranges of 0.01−10.00 ng/ml. The results of intra and inter-day precisions were both within 15%. The recovery rate was 85.5%−93.1%. Matrix effect was 91.2%−95.6%. Samples remained stable during analysis. Compared with the control group, cmax、AUC(0−t)、AUC(0−∞) and Vz of dexmedetomidine in the patients with obstructive jaundice were increased by 63.4%, 78.9, 66.4%, 82.5%, respectively (P<0.01). CLz was decreased by 42.1%. Conclusion This method is accurate, sensitive and reproducible. It is suitable for dexmedetomidine assay in human plasma. The elimination rate of dexmedetomidine is slower in obstructive jaundice.
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Objective To develop a high-performance liquid chromatography-diode array detector (HPLC-DAD) method for determination of cinnamic acid in the decoction of cinnamon, and investigate the effect of different storage temperature and time for the stability of cinnamic acid. Methods An HPLC- DAD method was established. Separation was performed on an Agilent Zorbax C18 column (4.6 mm×250 mm, 5 μm) with 0.1% formic-acetonitrile acid water solution (60:40) as the mobile phase by isocratic elution. The flow rate was 1.0 ml/min, the temperature of column was 25 ℃, the injection volume was 5 μl, the detective UV wave length was 275 nm. The decoction were stored under refrigerated temperature (4 ℃) ambient temperature (25 ℃) and high temperature (40 ℃). The cinnamic acid was detected after 0, 1, 3, 7, 14, 21, 30 d. Results Cinnamic acid was successfully separated by this method, with good linear relationship between 10.21-204.20 μg/ml. The precision, repeatability, stability and recovery were good. Compared with the zero day, the content of cinnamic acid in the decoction of cinnamon decreased significantly (P<0.01) after 21 days and 30 days of ambient temperature storage and after 14 days, 21 days and 30 days of high temperature storage, but no significant change was found in the other groups (P>0.05). Conclusion This HPLC-DAD method had good stability and repeatability. Cinnamic acid was stable in the decoction of cinnamon for 30 days under refrigerated temperature.
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Objective To develop a new method to determine the contents of rutaecarpine in Fuzhengpingxiao capsule by HPLC method.Methods Samples were handled by ethanol and extraction with ethyl acetate.The separation was achieved on an Agilent TC-C18column using a mobile phase system of acetonitrile-water(2% Tetrahydrofuran and 0.2 % formic acid)at a flow rate of 1.0 ml/min.The temperature of column was 40 ℃ and the detection wavelength was 240 nm.Results The cali-bration curves of rutaecarpine showed good linearity in the ranges of 1.18-118 μg/ml,r=0.999 9.The results of intra-day and inter-day precisions were both within 2%,the average additional recovery rate was 94.20%.Conclusion The HPLC method was accurate,specific,sensitive and reproducible,which could be used for quality control of rutaecarpine in the preparation of Fuzhengpingxiao capsule.
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Twenty-five hybrid dogs were injected intravenously with oleic acid of the dose 0.3 ml/kg of body weight to prepare a model of respiratory distress syndrome (RDS) . The animals were killed 24 hours after injection. PaO2, PaCO2 and pH of the arterial and mixed venous blood were determined before and immediately, 0.5, 1?2, 4, 6, 22 and 24 hours after injection. The average pulmonary arterial pressure was measured hourly. The chest x-ray films were taken 2,4, 6 and 24 hours after injection. The electrolytes T3, T4, the hematocrit and RBC count, and the serum corticosteroid level were measured before and 24 hours after injection.25 dogs were divided into two groups; the control group consisted of 8 dogs and the therapeutic group consisted of 17 dogs, among which nine were treated with hyosine hydrobromide and 8 with dexamethasone. The histologic specimens of the animals of the control group and hyosine hydrobromide treated group were examined with both light and electron microscopes but the specimens of the animals of dexamethasone treated group were examined with light microscope only.It was found that dexamethasone is effective in the treatment of RDS produced with oleic acid injection while hyosine hydrobromide is of no value.