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EN
A sensitive and reproducible HPLC method has been developed for quantitative analysis of telmisartan. The drug was separated from its degradation products on a C 18 column at ambient temperature with methanol-water 80:20 ( v / v ), pH 4.0 (adjusted by addition of orthophosphoric acid), as mobile phase at a flow rate of 1.0 mL min -1. Under these conditions the retention time of telmisartan was 4.85 ± 0.05 min. Quantification on the basis of peak area was achieved by UV detection at 225 nm; calibration plots were linear in the concentration range 10–60 μg mL -1 When the method was applied to a pharmaceutical formulation there was no chromatographic interference from tablet excipients. The method was validated for precision, robustness, recovery, and limits of detection and quantification. The drug was subjected to acidic and alkaline hydrolysis, and oxidising, dry heat, wet heat, and photodegrading conditions. Because the method could effectively separate the drug from its degradation products, it can be regarded as stability indicating.
EN
A sensitive, accurate, and robust high-performance thin-layer chromatographic (HPTLC) method has been established for simultaneous analysis of wedelolactone (WED) and asiaticoside (ASI) in Eclipta alba and Centella asiatica Linn., respectively. Chromatography was performed on silica gel with toluene-acetone-methanol-formic acid 3.0:2.0:2.0:0.05 ( υ/υ ) as mobile phase. Densitometric scanning at 317 nm for WED and at 530 nm, after derivatisation with 10% methanolic sulphuric acid, for ASI was used. The method was validated in accordance with the guidelines of the International Conference on Harmonization (ICH). R F values of 0.26 and 0.75 were obtained for ASI and WED, respectively. The linear ranges were 50–250 and 150–550 ng per band for WED and ASI, respectively, with good correlation coefficients ( r 2 = 0.999 and 0.9989, respectively). Accuracy was 99.29% and 99.45% for WED and ASI, respectively. The method was found to be precise, robust, and suitable for routine quality-control analysis of plant extracts and polyherbal formulations.
EN
A simple, sensitive, and reproducible high-performance thin-layer chromatographic method has been established for simultaneous analysis of trigonelline and 4-hydroxyisoleucine from fenugreek seeds ( Trigonella foenum-graceum ). Chromatography was performed on silica gel GF 254 with n -butanol-methanol-acetic acid-water 4:1.5:1:1 (υ/υ) as mobile phase. Densitometric scanning of the plates at 266 nm was used for analysis of trigonelline, and plates were scanned at 395 nm after derivatisation with ninhydrin reagent for analysis of 4-hydroxyisoleucine. The method was validated for specificity, precision (intraday and interday), accuracy, and robustness. Response was a linear function of the concentration of standard solutions in the range 100 to 1000 ng per band and 50 to 500 ng per band, respectively, with correlation coefficients of 0.9992 š 0.04 and 0.9986 š 0.06, for trigonelline and 4-hydroxyisoleucine. The accuracy of the method was checked by determination of recovery at three different levels; average percentage recovery was 99.39 š 0.34 for trigonelline and 99.03 š 0.26 for 4-hydroxyisoleucine. The method was found to be simple, precise, specific, sensitive, and accurate and can be used for routine quality control of fenugreek seeds and also for quantitative analysis of these marker compounds in processed fenugreek and its marketed preparations.
EN
Development, optimization, and validation of new analytical methods for standardization of bacoside A3 and bacopaside II, the major triterpenoid saponins present in Bacopa monnieri extract, are needed to improve the quality assurance of derived extracts and phytomedicines. Two chromatographic methods are described for evaluation of the quality of Bacopa monnieri extract and its commercial formulations. The first is reversed-phase high-performance thin-layer chromatography (RP-HPTLC), the second is packed column supercritical-fluid chromatography with photodiode- array detection (PC–SFC–DAD). SFC conditions were optimized by uniform design. The effect of temperature on the separation of the saponins was studied in detail. The Van’t Hoff plots for retention and selectivity were found to be linear. To obtain a better understanding of the different separations, the temperature dependence was studied to determine the thermodynamic data ΔH°, ΔS°, Δ ΔH° and Δ ΔS°. These data revealed that separation of bacoside A3 was enthalpically favoured in the range of temperatures investigated whereas entropy-controlled separation was observed for bacopaside II. Both methods were validated for precision, robustness, recovery, and limits of detection and quantitation. Analysis of variance (ANOVA) and Student’s t-test were used to correlate results from quantitative determination of the markers by RP-HPTLC and PC-SFC–DAD.
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