75 resultados para Méthode de quantification
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The development of a new methodology for the construction of very efficient flow cells for mercury detection by potentiometric stripping analysis, employing the thin gold layer of recordable CDs as working electrode is reported. This new source of electrodes (CDtrodes) show very attractive performance, similar to that obtained with commercial gold electrodes, with superior versatility. The low cost of this new source of gold electrodes allows a frequent replacement of the electrode, avoiding cumbersome clean-up treatments. Various experimental parameters have been optimized to yield low detection limits (0.25 ng/mL of mercury for 5 min deposition at 0.3 V) and good precision (standard deviation of 1.9% was obtained for 15 repetitive measurements using 10 ng/mL of mercury). Standard curves were found to be linear over the range of 0.5-100 μg L-1 of mercury. The flow cells developed were used for the quantification of mercury in oceanic and tap water. © Springer-Verlag 2000.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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A stability-indication high performance liquid chromatographic method has been developed for the determination of norfloxacin in tablet dosage forms. Optimum separation was achieved in less than 7 minutes using Eclipse Plus Zorbax C18 Agilent, 150 mm×4.6 mm i.d., 5 μm particle size column. The analyte was resolved by using a mobile phase 5% acetic acid aqueous solution and methanol (80:20, v/v) at a flow rate 1.0 ml/min on an isocratic high performance liquid chromatographic system at a wavelength of 277 nm. Linearity, system suitability, precision, sensitivity, selectivity, specific, and robustness were established by International Conference Harmonization guidelines. For stress studies the drug was subjected to photolysis, oxidation, acid, alkaline and neutral conditions. The analytical conditions and the solvent developed provided good resolution within a short analysis time and economic advantages. The proposed method not required sophisticated and expensive instrumentation.
Validation of analytical methodology for quantification of cefazolin sodium by liquid chromatography
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A reversed-phase high performance liquid chromatography method was validated for the determination of cefazolin sodium in lyophilized powder for solution for injection to be applied for quality control in pharmaceutical industry. The liquid chromatography method was conducted on a Zorbax Eclipse Plus C18 column (250 x 4.6 mm, 5 μm), maintained at room temperature. The mobile phase consisted of purified water: acetonitrile (60: 40 v/v), adjusted to pH 8 with triethylamine. The flow rate was of 0.5 mL min-1 and effluents were monitored at 270 nm. The retention time for cefazolin sodium was 3.6 min. The method proved to be linear (r2 =0.9999) over the concentration range of 30-80 µg mL-1. The selectivity of the method was proven through degradation studies. The method demonstrated satisfactory results for precision, accuracy, limits of detection and quantitation. The robustness of this method was evaluated using the Plackett–Burman fractional factorial experimental design with a matrix of 15 experiments and the statistical treatment proposed by Youden and Steiner. Finally, the proposed method could be also an advantageous option for the analysis of cefazolin sodium, contributing to improve the quality control and to assure the therapeutic efficacy
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Aims: Darunavir is widely used in HIV/AIDS therapy. It is a HIV protease inhibitor that has excellent efficacy against the virus. The aim of this study is to develop and validate an analytical method fast and free of interferences for determination of darunavir ethanolate as raw material and tablet dosage form. Methodology: As the formulation excipients show high interference in darunavir determination by a direct UV absorption measurement a derivative spectrophotometry was applied. A selective, easy and fast method was achieved employing simple and cheap instrumentation by using first-order derivative spectrophotometry. Results: The first-derivation of spectrum of the drug measured between 200 and 400 nm allowed identification of the analyte and showed absence of placebo interference. The assay was based on the absorbance at 276nm. The linear concentration range was established from 11 to 21 μg/mL. The intra-day and inter-day precision expressed as RSD was 0.06% and 3.75% respectively with mean recovery of 99.84%. Conclusion: The proposed analytical method is able to quantify darunavir as raw material and tablets and can be used routinely by any laboratory applying a spectrophotometer with a derivative accessory. The great difference of the method proposed here is that it proves to be free of placebo interferences as well as simple, fast and low cost.
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Darunavir, a protease inhibitor used in the treatment of HIV infection, presents few methods for its determination in pharmaceuticals. Infrared (IR) spectroscopy offers the possibility of obtaining spectra relatively quickly, providing interesting information, analytically, qualitatively or quantitatively. Capillary electrophoresis (CE) performs separations of high efficiency in shorter time with reagents and samples in small quantity. These two methods are cost-benefitted when we evaluate the green level and the cost of analysis. Faster and cheaper methods without generating organic waste by IR and CE for the quantification of darunavir were developed and validated, focusing socioeconomic impact of analytical decisions. If the cost of acquisition, maintenance, production, analysis and conditioning of drugs and pharmaceuticals is high, consequently the price of this product in the market will be higher and it cannot be accessible to the patient. Treatment failure not only affects the quality of life of patients, but also contributes significantly to the economic burden of the health system. In this context there is a tool called Analysis of the Life Cycle, which comes to make us think in a multidimensional way focusing the whole, the parts and especially the interaction among the parts of a system.
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SUMMARY. A new method was developed to evaluate the total antioxidant activity in plant extracts, which was based on radical scavenging using 2,2’-azinobis-(3-ethylbenzothiazoline)-6-sulfonic acid. The proposed method was linear in the range of 0.86 to 26.0 μg/mL, displaying a correlation coefficient of 0.999. Moreover, the accuracy and precision analysis showed agreement with ANVISA guidelines (96.66 to 98.46 % and < 5.0%, respectively). The method demonstrated sensitivity, robustness and efficiency in detecting low concentrations of plant extracts (detection and quantification limit of 0.86 and 2.87 μg/mL, respectively) that may be present in pharmaceuticals and cosmetics preparations, again in agreement with ANVISA. In addition, the assay is inexpensive and easy to perform.