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Zero crossing and ratio spectra derivative spectrophotometry for the dissolution tests of amlodipine and perindopril in their fixed dose formulations

in bulk and tablet dosage form by HPLC. Indian Drugs, 50, 32, 2013. 7. Prajapati J. et al.: Analytical method development and validation of amlodipine besylate and perindopril erbumine in combine dosage form by RP-HPLC. Int. J. PharmTech. Res., 3, 801, 2011. 8. Ram C.V.S. et al.: Comparative effectiveness analysis of amlodipine/ renin angiotensin system blocker combinations. J. Clin. Hypertens., 14, 601, 2012. 9. Rojas F.S., Ojeda C.B.: Recent development in derivative ultraviolet/ visible absorption spectrophotometry

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Selective determination of Fe(III) in Fe(II) samples by UV-spectrophotometry with the aid of quercetin and morin

-Füchsel and M. Balcerzak, Speciation analysis of osmium (VIII) and osmium(IV) by UV-VIS spectrophotometry using quercetin as the reagent, Anal. Lett. 39 (2006) 589-602; DOI: 10.1080/00032710500535881. International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use, ICH Harmonized Tripartite Guideline, Validation of Analytical Procedures: Text and Methodology Q2(R1) , Current Step 4 version, Nov 1996, Geneva, Nov 2005.

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Contribution to Casein Determination by UV Spectrophotometry

References 1. Kamizake, N. K.; Gonçalves, M. M.; Zaia, C. T; Zaia, D. A. Determination of total proteins in cow milk powder samples: a comparative study between the Kjeldahl method and spectrophotometric methods. J. Food Comp. Anal. 2003 , 16 , 507-516. 2. Laporte, M. F.; Paquin, P. Near-infrared analysis of fat, protein, and casein in cow's milk. J. Agric. Food Chem. 1999 , 47 , 2600-2605. 3. Lüthi-Peng, Q.; Puhan, Z. Determination of protein and casein in milk by fourth derivative UV spectrophotometry. Anal. Chim. Acta 1999

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Comparison of high-performance thin layer chromatography/UV-densitometry and UV-derivative spectrophotometry for the determination of trimetazidine in pharmaceutical formulations

products, J. AOAC Int. 87 (2004) 827–833. 10. M. Gackowski, M. Koba and K. Mądra-Gackowska, Determination of lormetazepam in tablets using high-performance liquid chromatography, and derivative spectrophotometry methods, J. Planar Chromatogr. - Mod. TLC 31 (2018) 235–242; https://doi.org/10.1556/1006.2018.31.3.9 11. M. Gackowski, M. Koba and S. Kruszewski, Comparison of UV- and derivative-spectrophotometric and HPTLC UV-densitometric methods for the determination of amrinone and milrinone in bulk drugs, Curr. Pharm. Anal. 14 (2018) 1–8; https

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Letrozole Determination by Capillary Zone Electrophoresis and UV Spectrophotometry Methods

Abstract

Objective: Letrozole is a highly potent oral nonsteroidal aromatase inhibitor triazole derivative. The aim of this study was to quantify letrozole from bulk, pharmaceutical formulation, and spiked urine samples by developing a simple, rapid and cost effective capillary electrophoresis method. Methods: A capillary zone electrophoresis method was optimized and validated. Additionally, an UV spectrophotometry method was used for comparing results. Results:The capillary zone electrophoresis method using a 90 mM sodium tetraborate background electrolyte proved to be an efficient method for determination of letrozole in a very short time, less than 2 minutes, using 20 kV voltage, 50 mbar/2 seconds pressure and 50°C temperature as optimum parameters. Additionally, the UV spectrophotometry method proved to be simple and efficient to quantify letrozole from bulk material and pharmaceutical formulation with linearity of response between 5 to 20 μg·mL-1 concentrations. For both methods, validation parameters, including linearity, detection and quantification limits were determined. Also we proved that our electrophoretic method has potential in analyzing letrozole from biological samples, obtaining encouraging results on estimation of letrozole from spiked urine samples without any special treatment. Conclusions: To quantify letrozole from bulk material, pharmaceutical preparations, and spiked urine samples the capillary zone electrophoresis method using a tetraborate sodium background electrolyte has proven to be simple and appropriate. Also a simple UV spectrophotometric method has been developed and validated for the same purposes.

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High-performance liquid chromatography and derivative spectrophotometry for simultaneous determination of pravastatin and fenofibrate in the dosage form

Abstract

High performance liquid chromatography (HPLC) and second-order derivative spectrophotometry have been used for simultaneous determination of pravastatin (PS) and fenofibrate (FF) in pharmaceutical formulations. HPLC separation was performed on a phenyl HYPERSIL C18 column (125 mm × 4.6 mm i.d., 5 μm particle diameter) in the isocratic mode using a mobile phase acetonitrile/0.1 % diethyl amine (50:50, V/V, pH 4.5) pumped at a flow rate of 1.0 mL min-1. Measurement was made at 240 nm. Both drugs were well resolved on the stationary phase, with retention times of 2.15 and 5.79 min for PS and FF, respectively. Calibration curves were linear (R = 0.999 for PS and 0.996 for FF) in the concentration range of 5-50 and 20-200 µg mL-1 for PS and FF, respectively. Pravastatin and fenofibrate were quantitated in combined preparations also using the second-order derivative response at 237.6 and 295.1 nm for PS and FF, respectively. Calibration curves were linear, with the correlation coefficient R = 0.999 for pravastatin and fenofibrate, in the concentration range of 5-20 and 3-20 µg mL-1 for PS and FF, respectively. Both methods were fully validated and compared, the results confirmed that they were highly suitable for their intended purpose.

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Comparison of classic and derivative UV spectrophotometric methods for determination of dextromethorphani hydrobromidum

, Bosch OC. Recent development in derivative ultraviolet/visible absorption spectrophotometry: 2004-2008: a review. Anal Chim Acta. 2009;635:22-44.

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Spectrophotometric method for simultaneous determination of valsartan and substances from the group of statins in binary mixtures

hydrochlorothiazide in tablets by first-derivative ultraviolet spectrophotometry and LC, J. Pharm. Biomed. Anal. 25 (2001) 1009-1013; https://doi.org/10.1016/S0731-7085(01)00394-6 14. M. M. Deshpande, M. P. Mahajan and S. D. Sawant, Simultaneous estimation of valsartan and hydrochlorothiazide in fixed dose combination in UV spectrophotometry, Int. J. Pharm. Sci. Res. 3 (2012) 236-240. 15. T. A. Wani, A. Ahmad, S. Zargar, N. Y. Khalil and I. A. Darwish, Use of response surface methodology for development of new microwell-based spectrophotometric

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Determination of Trace Cadmium in Nonalcoholic Beverages by Coupling Cloud Point Extraction with Spectrophotometry

Abstract

A cloud-point extraction (CPE) process using the nonionic surfactant, Triton X-114 to extract Cd(II) ions from aqueous solutions was investigated. The method is based on the ion-pairing reaction of Cd(II) with Victoria blue B (VBB+) in presence of excess iodide at pH 4.0 and extraction of the complex formed. The chemical variables affecting CPE efficiency were studied, and the analytical characteristics of the method were obtained. The calibration curves were obtained in the ranges of 1.0-30 and 10-500 μg/L for Cd(II) ion with the detection limits of 0.34 and 3.8 μg/L at 608 and 634 nm, respectively. The selectivity study was also tested. The precision (N: 5, 25 μg/L) was 2.85% relative standard deviation. The results obtained for two certified reference samples were in a good agreement with the certified values. The method was successfully applied to the determination of Cd(II) in beverage samples.

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2-(4-Diethylaminostyryl)-1,3,3-trimethyl-5-thiocyanato-3H-indolium chloride as a new reagent for indirect spectrophotometric red-ox determination of Osmium (VI)

high molecular weight amines prior to simultaneous determination by derivative spectrophotometry. Analusis , 27, 829-834. DOI: 10.1051/analusis:1999150. Beamish, F. E. (1966). The Analytical Chemistry of the Noble Metals , New York, Pergamon. Zolotov, Yu. A., Varshal, G. M. & Ivanov, V. M. (2003). Analyticheskaya khimiya metallov platinovoi gruppy (Analytical Chemistry of Platinum-Group Metals) , Moscow, Editorial URSS. Balcerzak, M. (2002). Sample Digestion Methods for the Determination

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