Wang M.,Guangdong Pharmaceutical University |
Wang M.,Guangdong Key Laboratory of Molecular Epidemiology |
Li S.,Guangdong Pharmaceutical University |
Li S.,Guangdong Key Laboratory of Molecular Epidemiology |
And 7 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2014
Cloud point extraction (CPE) is proposed as a pre-concentration procedure for the determination of Hg in Chinese herbal medicine samples by hydride generation-atomic fluorescence spectrometry (HG-AFS). Hg2+ was reacted with dithizone to form hydrophobic chelate under the condition of pH. Using Triton X-114, as surfactant, chelate was quantitatively extracted into small volume of the surfactant-rich phase by heating the solution in a water bath for 15 min and centrifuging. Four variables including pH, dithizone concentration, Triton X-114 concentration and equilibrium temperature (T) showed the significant effect on extraction efficiency of total Hg evaluated by single-factor experiment, and Box-Behnken design and response surface methodology were adopted to further investigate the mutual interactions between these variables and to identify their optimal values that would generate maximum extraction efficiency. The results showed that the binomial was used to fit the response to experimental levels of each variable. ALL linear, quadratic terms of four variables, and interactions between pH and Trion X-114, pH and dithizone affected the response value(extraction efficiency) significantly at 5% level. The optimum extraction conditions were as follows: pH 5.1, Triton X-114 concentration of 1.16 g·L-1, dithizone concentration of 4.87 mol·L-1, and T 58.2°C, the predicted value of fluorescence was 4 528.74 under the optimum conditions, and the experimental value had only 2.1% difference with it. Under the conditions, fluorescence was linear to mercury concentration in the range of 1~5 μg·L-1. The limit of detection obtained was 0.012 47 μg·L-1 with the relative standard deviations (R. S. D.) for six replicate determinations of 1.30%. The proposed method was successfully applied to determination of Hg in morindae Radix, Andrographitis and dried tangerine samples with the recoveries of 95.0%~100.0%. Apparently Box-Behnken design combined with response surface analysis method was considered to be well used for optimization of the cloud point extraction.
Peng Y.,Guangdong Pharmaceutical University |
Peng Y.,Guangdong Key Laboratory of Molecular Epidemiology |
Chen X.-F.,Guangdong Pharmaceutical University |
Chen X.-F.,Guangdong Key Laboratory of Molecular Epidemiology |
And 4 more authors.
Chinese Journal of Evidence-Based Medicine | Year: 2013
Objective To systematically review the effectiveness and safety of linezolid versus teicoplanin in patients with MRSA pneumonia. Methods Such databases as CBM, CNKI, WanFang Data, VIP, Science Direct, PubMed, Ovid, SciFinder, The Cochrane Library (Issue 3, 2013) and EMbase were electronically searched for published articles (randomized controlled trials or non-randomized prospective trials with comparable baseline between groups) at home and abroad on the clinical effectiveness and safety of linezolid versus teicoplanin in patients with MRSA pneumonia from January 2003 to March 2013. Using the Cochrane methods, two reviewers independently screened literature, extracted data, and assessed the methodological quality of included studies. Then, meta-analysis was performed using RevMan 5.2 software in clinical cure rates, clinical effective rates, microbiologic eradication rates, and adverse reaction incidences. Results Finally, 7 studies were included involving 637 patients. The results of meta-analysis were clinical effective rates (RR=1.17, 95%CI 1.04 to 1.32, P=0.009), clinical cure rates (RR=1.06, 95%CI 0.94 to 1.19, P=0.37), bacterial clearance rates (RR=1.32, 95%CI 1.03 to 1.68, P=0.03), and adverse events rates (RR=1.24, 95%CI 0.78 to 1.97, P=0.37). The results of Begg test and Egger test were not significant (P>0.05). Conclusion Current evidence shows that, in treating MRSA pneumonia, linezolid is better than teicoplanin in clinical effective rates and bacterial clearance rates. However, they are alike in clinical cure rates and bacterial clearance rates. © 2013 Editorial Board of Chin J Evid-based Med.