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Biomedical subjects

K D Altria

Publications and source records attributed to K D Altria.

44 records · Page 3Linked to original sources
PubMed1994

Enantiomeric separation of salbutamol and related impurities using capillary electrophoresis.

The enantiomeric resolution of salbutamol and its chiral and achiral related impurities is investigated using capillary electrophoresis. The effects of nine varieties of cyclodextrin, cyclodextrin concentration and organic modifier concentration were studied in an attempt to resolve all possible analytes in a complex mixture of salbutamol-related solutes. Eleven components including three enantiomeric pairs were baseline resolved using 112 mM dimethyl-beta-cyclodextrin at pH 2.5 in a citric acid/phosphate buffer. Both methanol and iso-propyl alcohol at up to 20% were found to have a deleterious effect on the separation. Binding constants and mobility values for the free and complexed forms for each solute were determined. The results are interpreted by considering the physical properties of the molecules under the conditions employed and a rationale proposed for the underlying basis for chiral and achiral selectivity.

Albuterol↗
PubMed1994

Quantitative applications and validation of the resolution of enantiomers by capillary electrophoresis.

The separation and quantitation of enantiomers is an important application of capillary electrophoresis. This paper reviews the performance and validation of capillary electrophoretic methods for this application. Limits of detection of < 0.1% are shown for determinations of minor enantiomer levels. Application areas include enantiomeric purity testing of pharmaceuticals and herbicides, reaction rate monitoring, stability testing, and clinical analysis. It is concluded that the number of quantitative application areas will undoubtedly expand as capillary electrophoresis becomes more widely established as an alternative and complement to high-performance liquid chromatography.

Artifacts↗
PubMed1993

Enantioselective enzymatic biotransformation of 2'-deoxy-3'-thiacytidine (BCH 189) monitored by capillary electrophoresis.

Concentrations of the enantiomers of 2'-deoxy-3'-thiacytidine (BCH 189) have been monitored during enantiospecific biotransformation catalyzed by cytidine deaminase. This enzymatic reaction is monitored by capillary electrophoresis (CE) over a 51-h time period. The use of dimethyl-beta-cyclodextrin as a chiral electrolyte additive in a pH 2.3 phosphate buffer system gives enantiomeric separation with results for peak efficiencies, resolution, and analysis time of the order of 25,000 plates, > 1.5 and 30 min, respectively. The features of the CE method are compared with those of the previously favored chiral HPLC method.

Antiviral Agents↗
PubMedDate not supplied

Main component assay of pharmaceuticals by capillary electrophoresis: considerations regarding precision, accuracy, and linearity data.

Capillary electrophoresis has been successfully employed to determine the level of drugs in a variety of pharmaceutical preparations. A large number of reports have shown agreement between CE results and HPLC data or with label claim. Currently the use of CE for main component assays constitutes 26% of the routine usage of CE within drug companies and is the most frequent application. The choice between adopting CE or HPLC for a particular application is very dependent upon the relative merits of each technique to the individual assay. Often, CE can have advantages in terms of reduced sample pretreatment, consumable costs, and analysis time. The ability to separate a wide range of solutes using a single set of operating conditions is a strong advantage of CE. This paper extensively reviews the literature reports of the use of CE for main peak assay and indicates the validation performance data achieved. The specific requirements relating to optimized accuracy and precision in CE assay are discussed in some detail. The use of an appropriate internal standard to improve performance for precision, accuracy, and linearity, and to reduce the impact of sample matrix effects, is experimentally shown by results from the analysis of levothyroxine samples. The applications are subdivided into those samples analyzed by free solution capillary electrophoresis (FSCE) at low or high pH or those separated by micellar electrokinetic capillary electrophoresis (MECC).

Chromatography, High Pressure Liquid↗