Analysis of Some Drug Substances by High-Performance Liquid Chromatography

Achari, Raja G.; Theimer, Edgar E.

doi:10.1093/chromsci/15.8.320

Cited by 35 publications

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“…However, if the feasibility of a potential buffer is checked only from the aqueous p K a value and useful pH range, once again one may arrive at wrong conclusions. For example, it is commonly believed that ammonia buffers are too basic to be used in silica-based columns, although extensive use of them in methanol-rich mixtures (80−90%) has been reported with no apparent attack of the silica column. − This mobile phase is particularly useful for many basic drug separations. Figure clearly shows that the p K a of ammonium is outside the useful pH range for most methanol−water compositions, but inside for methanol contents higher than 75%.…”

Section: Ph Scale In Methanol−water and Useful Ph Range For Hplcmentioning

confidence: 99%

Retention of Ionizable Compounds on HPLC. pH Scale in Methanol−Water and the pK and pH Values of Buffers

et al. 1996

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Several properties of methanol-water mixtures (molar volume, molar refractivity, Debye-Hu 1 ckel parameters, pH scale, HPLC-useful pH range, dissociation constants of acids) are studied. Some macroscopic properties are used to calculate the extent of the methanol-water interaction. Solute properties, such as pK a values, depend on the preferential solvation of the solute by the three solvents that coexist in the mixture (methanol, water, methanol-water aggregrates). Based on this preferential solvation and on the methanol-water interaction, equations that relate the pK a values of acids with the solvent composition are derived. The equations are applied to several acids widely used to prepare HPLC buffers. The pK a of an acid and the pH of a buffered solution at any methanol-water composition can be easily calculated from the proposed equations. The chromatographic retention of any solute can be thus related to the real pH value of the mobile phase used. This procedure is more rigorous and should give better results than the usual method of relating the retention to the pH value of the aqueous buffer before mixing it with methanol.

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Section: Ph Scale In Methanol−water and Useful Ph Range For Hplcmentioning

confidence: 99%

Retention of Ionizable Compounds on HPLC. pH Scale in Methanol−Water and the pK and pH Values of Buffers

et al. 1996

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“…Thus there arose the need to measure unreacted strychnine in urine and other biological fluids. Colour reactions (12), measurement of absorbance at one or two wavelengths after Separation (13-15), double labeling techniques (16), GLC Separation (17), and existing HPLC methods for grain baits (18) (19,20) were unsatisfactory in one or more respects. The interesting reversed phase HPLC method oiCrouch &Short (21) did not separate strychnine from brucine except by use of a solvent gradient.…”

Section: Introductionmentioning

confidence: 99%

A New High Performance Liquid Chromatography (HPLC) Method for the Quantitation of Strychnine in Urine and Tissue Extracts

Egloff¹,

Niederwieser²,

Pfister³

et al. 1982

CCLM

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A high performance liquid chromatography (HPLC) method was developed for the quantitation of strychnine in urine of children with noiiketotic hyperglycinaemia and other developmental disorders treated with the alkaloid. Mobile and stationary phases were polar, i.e. methanol-water-330 g/kg ammonia (volumes, 85 ml + 14.2 ml + 0.8 ml) and LiGhrosorb Si-60,7. Brucine was the internal Standard. Extraction was perfbrmed by the Extrelut technique. At strychnine nitrate concentrations in urine of 21,126, and 760 g/l, recovery was 92.1 ± 8.7, 98.1 ± 2.7, and 102.5 ± 2.7%. A child with nonketotic hyperglycinaemia under continued strychnine treatment excreted l to 13.6% of the daily dose unmetabolized in urine. The method was also suitable for the estimation of unreacted strychnine in tissue extracts. The fast disappearance in vitro of strychnine from a guinea pig liver preparation was confirmed. Eine neue Methode für die quantitative Bestimmung von Strychnin in Harn und Gewebsextrakten mit Hochleistungsflüssigkeitschromatographie (HPLC) Zusammenfassung: Zur Bestimmung von Strychnin im Harn von Kindern mit nicht-ketotischer Hyperglycinämie und anderen Entwicklungsstörungen, die mit dem Alkaloid behandelt werden, wurde eine Methode unter Verwendung der Hochleistungsflüssigkeitschromatographie (HPLC) entwickelt. Mobile und stationäre Phase waren polar, es wurden Methanol/Wasser/330 g/kg Ammoniak (Volumina, 85 ml + 14,2 ml + 0,8 ml) und LiChrosorb Si-60, 7 , verwendet. Brucin diente als innerer Standard. Die Extraktion würde mit der Extrelut-Technik durchgeführt. Die Wiederfindung für Strychninnitrat-Konzentrationen im Harn von 21,126 und 760 /zg/1 betrug 92,

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Simultaneous High-pressure Liquid Chromatographic Determination of Acetaminophen, Guaifenesin, and Dextromethorphan Hydrobromide in Cough Syrup

McSharry

Savage²

1980

Journal of Pharmaceutical Sciences

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Analysis of Some Drug Substances by High-Performance Liquid Chromatography

Abstract: A high-performance liquid chromatographic system using a silica gel column and methylene chloride:methanol:ammonium hydroxide as a solvent for the analysis of some drug substances is described. The procedure described is suitable for the analysis of pharmaceutical dosage forms.

Cited by 35 publications

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Retention of Ionizable Compounds on HPLC. pH Scale in Methanol−Water and the pK and pH Values of Buffers

Retention of Ionizable Compounds on HPLC. pH Scale in Methanol−Water and the pK and pH Values of Buffers

A New High Performance Liquid Chromatography (HPLC) Method for the Quantitation of Strychnine in Urine and Tissue Extracts

Simultaneous High-pressure Liquid Chromatographic Determination of Acetaminophen, Guaifenesin, and Dextromethorphan Hydrobromide in Cough Syrup

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