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Du B.,Zhengzhou University | Li H.,Zhengzhou University | Jin J.,Zhengzhou University | Wang T.,Zhengzhou University | And 3 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

A novel and rapid method for the determination of streptomycin has been established by chemiluminescence (CL) based on significant intensity enhancement of streptomycin on the weak CL of N-bromosuccinimide (NBS) and eosin in alkaline medium. The method is simple, rapid and effective to determine streptomycin in the range of 8.0 × 10 9-1.0 × 10 6 g mL1 with a determination limit of 2.25 × 10 9 g mL 1. The relative standard deviation is 1.95% for the determination of 2.0 × 10 7 g mL1 streptomycin (n = 11). The pharmacokinetics of streptomycin in plasma of rat coincides with the two-compartment open model. The T1/2α, T1/2β, CL/F, AUC(0 t), MRT, Tmax and Cmax were 18.83 ± 1.24 min, 82.14 ± 3.07 min, 0.0026 ± 0.0011 L kg1 min 1, 36044.50 ± 105.02 mg min 1L 1, 92.29 ±8.21 min, 21.63 ± 1.26 min and 375.61 ± 8.50 μg mL 1, respectively. There was no significant difference between the results obtained by CL and HPLC. The FI-CL method can be used to determine streptomycin in pharmaceutical preparation and biological samples. The established method is simple, rapid and sensitive without expensive instruments. The possible enhancement mechanism was also investigated. © 2013 Elsevier B.V. All rights reserved. Source

Du B.,Zhengzhou University | Pang L.,Zhengzhou University | Li H.,Zhengzhou University | Ma S.,Zhengzhou University | And 3 more authors.
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences

This investigation describes a precise and accurate stereoselective HPLC method for the simultaneous determination of indapamide enantiomers in whole blood to follow its pharmacokinetics in rats up to 24. h after single oral dosing. Enantiomeric resolution was achieved on a cellulose tris (3,5-dichlorophenylcarbamate) column known as Chiralpak IC, with UV detection at 240. nm, and the mobile phase consisted of n-hexane and isopropanol (70:30, v/v). Using the chromatographic conditions described, indapamide enantiomers were well resolved with a resolution factor (Rs) of at least 2.0 and with retention times of 19.2 and 23.3. min, respectively. Linear responses (r>. 0.999) were observed over the range of 0.05-50. μg/mL of indapamide enantiomers, with quantitation limit of 0.05. μg/mL. The mean relative standard deviation (RSD) of within-day precision and accuracy of the drug were <10%. The mean extraction efficiency was greater than 86% for each enantiomer. The assay method shows good specificity to indapamide enantiomers, and it could be successfully applied to its pharmacokinetic studies and to therapeutic drug monitoring. © 2013 Elsevier B.V. Source

Huang M.,Zhengzhou University | Lv S.,Henan Provincial Institute of Food and Drug Control | Zhou C.,Zhengzhou University
Thermochimica Acta

The non-isothermal decomposition kinetics of glycine was investigated using analyzer DTG-60. TG experiments were carried out under dynamic nitrogen atmosphere of 30 mL min-1 with heating rates of 10, 14, 18 and 22 K min-1. The kinetic parameters such as activation energy (E), exponential factor (A) and reaction order (n) were evaluated by Flynn-Wall-Ozawa, Doyle, Kissinger and Šatava-Šesták methods. The results show that the non-isothermal decomposition mechanism of glycine corresponds to nucleation and growth, following the Avrami-Erofeev equation with n = 1/3. Moreover, thermodynamic properties of the non-isothermal decomposition process such as the change in the values of enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) were calculated. © 2012 Elsevier B.V. All rights reserved. Source

Liu Z.-P.,Zhengzhou University | Lu S.-C.,Henan Provincial Institute of Food and Drug Control | Zhou C.-R.,Zhengzhou University
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities

The thermal decomposition characteristics and kinetics of inositol were studied by DTA-TGA techniques. The curves of TGA and DTA of inositol at different heating rates (5, 10, 15, 20, 25°C · min-1) were acquired in nitrogen atmosphere. The kinetic parameters including the activation energy and pre-exponential factor of the thermal decomposition process for inositol were calculated by Flynn-Wall-Ozawa (FWO), Kissinger and Šatava-Šesták method, respectively. Moreover, the thermal decomposition mechanism of inositol was also studied. Results of this study show that the activation energy was found to be 208.03 kJ · mol-1, and logarithmic value of the pre-exponential factor logA was given to be 16.76. According to Šatava-Šesták method, the thermal decomposition mechanism of inositol was thought to be chemical reaction. Integral form of the most probable mechanism function of the decomposition process was obtained to be G(α)=(1-α)-1-1. Source

Xiang M.,Biotechnology Center | Wang J.,Suzhou Health College | Zhang Y.,Biotechnology Center | Ling J.,Suzhou Health College | Xu X.,Henan Provincial Institute of Food and Drug Control
Archives of Pharmacal Research

Vascular complications are the leading causes of morbidity and mortality in diabetes mellitus (DM). The RAGE (receptor for advanced glycation end products)-NADPH oxidase-NF-κB signal transduction pathway plays an important role in the development of oxidative stressrelated vascular complications in DM. Ursolic acid (UA), a pentacyclic triterpenoid derived from plants, has been reported to have multiple pharmacological effects, including a potent antioxidant activity. This study aimed to investigate both the effect of UA on aortic injury in streptozotocin (STZ)-induced diabetic rats and the drug's mechanism of action. STZ-induced diabetic animals were randomized in one of the following 4 groups: no treatment (diabetic model group), aminoguanidine (AG, 100 mg/kg), high-dose UA (50 mg/kg), and low-dose UA (25 mg/kg). A non-diabetic control group was followed concurrently. After 8 weeks, the diabetic model rats exhibited: severe aortic arch injury, histologically elevated serum glucose, fructosamine, and glycosylated hemoglobin; and accumulation of advanced glycation end products (AGEs) in the arota. In addition, the levels of RAGE protein, transcription factor NF-κB p65, and the p22phox subunit of NADPH oxidase were increased, as were the serum levels of malondialdehyde and tumor necrosis factor-alpha (TNF-α; p < 0.01 vs control), suggesting that the mechanisms of oxidative stress contributed to vascular injury in the diabetic model group. In contrast, rats treated with UA (50 mg/kg) had a markedly less vascular injury and significantly improved biochemical parameters. Oxidative balance was also normalized in the UAtreated rats, and a marked reduction in the levels of RAGE and p22phox paralleled the reduced activation of NF-κB p65 and TNF-α (p < 0.01 and p < 0.05, respectively, vs diabetic model). These findings suggest that UA may suppress oxidative stress, thus blunting activation of the RAGE-NADPH oxidase-NF-κB signal transduction pathway, to ameliorate vascular injury in the STZ-induced DM rats. Source

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