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Development of quantitative HPTLC–Densitometry methods for the analysis of amiodarone HCl, carvedilol, doxylamine succinate, magnesium salicylate, metoprolol succinate, nebivolol HCl, and salicylamide using a model process developed earlier for the transfer of TLC screening methods

Nguyen K., Sherma J.

Acta Chromatographica

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2018

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Vol. 30, no. 4

264--268

EN

A model process, previously developed in a series of studies, allows for the transfer of thin-layer chromatography (TLC) methods for qualitative screening of counterfeit drug products published in the Global Pharma Health Fund (GPHF) Minilab manual and US Food and Drug Administration (FDA) Compendium of Unofficial Methods for Screening of Pharmaceuticals by TLC to quantitative high-performance TLC (HPTLC)–densitometry methods. This article describes HPTLC–densitometry methods developed and validated according to this model process for pharmaceutical products of amiodarone HCl, carvedilol, doxylamine succinate, magnesium salicylate, metoprolol succinate, nebivolol HCl, and salicylamide, for which qualitative screening methods have not been published in the Minilab manual or FDA Compendium. These methods use relatively inexpensive and nontoxic “green solvents” for sample and standard solution and mobile phase preparation, Merck Premium Purity silica gel 60 F254 plates, automated standard and sample solution bandwise application, and automated densitometry for the assessment of peak purity and identity and quantification. Corresponding to the quantitative HPTLC–densitometry methods, qualitative TLC screening methods for these drug products were developed and posted online with open access as supplements to the FDA Compendium.

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TLC—Densitometric Determination of Sulfasalazine and Its Possible Impurities in Pharmaceutical Preparations

Kwiecień A., Piątek K., Żmudzki P., Krzek J.

Acta Chromatographica

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2015

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Vol. 27, no. 4

623--635

EN

A simple, selective, and sensitive thin-layer chromatographic—densitometric method has been developed for the determination of sulfasalazine besides its possible impurities in pharmaceutical preparations. The mobile phase was composed of ethyl acetate—methanol—ammonia 25% 10:7:3 (υ/υ/υ), and the stationary phase was aluminum plates precoated with silica gel 60 F254 that enabled to obtain well resolved peaks of sulfasalazine and its impurities. The developed chromatograms were analyzed densitometrically at λ = 360 nm. RF values and ultraviolet (UV) spectra were used to identify the compounds. The developed method is highly sensitive (limit of detection [LOD] = 17.11 ng spot−1, limit of quantitation [LOQ] = 51.84 ng spot−1), precise (relative standard deviation [RSD] = 1.43%–4.28%), and accurate (RSD = 1.64%–4.27%). The linearity of the method was checked within the range 20–120 ng spot−1. The method was successfully applied for the determination of sulfasalazine in pharmaceutical preparations besides its impurities. The structures of impurities present in the standard substance and in pharmaceutical preparations were established by ultra-performance liquid chromatography—tandem mass spectrometry (UPLC—MS/MS) technique.

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Transfer of TLC screening methods designed for use in developing countries to quantitative HPTLC-densitometry methods for diazepam and amodiaquine tablets

Popovic N., Sherma J.

Acta Chromatographica

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2014

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Vol. 26, no. 4

615--623

EN

Transfer of two rapid thin-layer chromatography (TLC) screening methods used to detect markedly substandard and fake pharmaceutical products to quantitative high-performance TLC (HPTLC)-densitometry methods is demonstrated using a model procedure that was published earlier. These TLC methods for diazepam and amodiaquine are contained in a Compendium of methods by Kenyon and Layloff and a Minilab method manual from Global Pharma Health Fund E.V., respectively, for use in countries with limited resources. Merck HPTLC Premium Purity silica gel 60 F254 glass plates, automated standard and sample solution application with a CAMAG Linomat 4, and automated densitometry with a CAMAG Scanner 3 were used for detection, identification, and quantification. Sample peak identity and purity validation were carried out by spectral comparison checks available in the winCATS software. Accuracy was estimated by the standard addition approach with overspotting standard and sample solutions. HPTLC gives better efficiency, selectivity, and resolution than TLC, and the new methods overcome the deficiencies in technology related to manual application and visual zone comparison that do not allow the Compendium and Minilab TLC procedures to support regulatory compliance actions. These new methods can be fully validated according to the International Conference on Harmonization guidelines or by interlaboratory studies if required by their applications.

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A model procedure for the transfer of TLC pharmaceutical product screening methods designed for use in developing countries to quantitative HPTLC-densitometry methods

O’sullivan C, Sherma J.

Acta Chromatographica

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2012

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Vol. 24, no. 2

241--252

EN

Transfer of four rapid thin-layer chromatography (TLC) screening methods used to detect substandard and counterfeit pharmaceutical products to quantitative high-performance TLC (HPTLC)-densitometry methods is demonstrated. These methods for acetaminophen, acetylsalicylic acid, ibuprofen, and chlorpheniramine maleate are contained in a Compendium of methods developed by Kenyon and Layloff for use in countries with limited resources. The new quantitative methods use Merck HPTLC silica gel 60 F254 glass plates, automated standard and sample application, and automated densitometry for detection, identification, and quantification. Standard and sample solution preparation and application procedures for obtaining calibration curves and bracketed samples are described. The HPTLC plates give better efficiency, selectivity, and resolution than TLC, and the new methods overcome the deficiencies in technology related to manual application and visual zone comparison that do not allow the Compendium TLC procedures to support regulatory compliance actions. These transferred methods can be fully validated according to International Conference on Harmonization (ICH) guidelines or by interlaboratory studies if their applications require. The approach described can be used to transfer the remaining Compendium methods as well as the GPHF [Global (formerly German) Pharma Health Fund E.V.] Minilab kit TLC screening methods.