Biomedical subjects

K D Altria

Publications and source records attributed to K D Altria.

At least 19 recordsLinked to original sources

PubMed1999

Overview of capillary electrophoresis and capillary electrochromatography.

This paper provides an overview on the current status of capillary electrophoresis (CE) and capillary electrochromatography (CEC). The focus is largely on the current application areas of CE where routine methods are now in place. These application areas include the analysis of DNA, clinical and forensic samples, carbohydrates, inorganic anions and metal ions, pharmaceuticals, enantiomeric species and proteins and peptides. More specific areas such the determination of physical properties, microchip CE and instrumentation developments are also covered. The application, advantages and limitations of CEC are covered. Recent review articles and textbooks are frequently cited to provide readers with a source of information regarding pioneering work and theoretical treatments.

Chromatography, Liquid↗

PubMed1999

Enantiomeric purity determination of propranolol by capillary electrophoresis using dual cyclodextrins and a polyacrylamide-coated capillary.

The use of a chirally selective capillary electrophoresis method is reported for the enantioselective purity determination of propranolol drug substance. The method employed a combination of both charged and neutral cyclodextrin. An internally coated capillary was used to suppress electroosmotic flow and potential peak tailing. The method was capable of monitoring below 0.1% m/m of the undesired impurity. Acceptable validation data was also obtained for recovery, linearity, and for both short and long-term injection precision.

Electrophoresis, Capillary↗

PubMed1998

Analysis of acidic compounds using capillary electrochromatography.

Capillary electrochromatography, CEC, is a hybrid of CE and HPLC and is rapidly gaining interest as a potential complementary technique. This paper provides an overview of literature concerning the separation of acidic compounds by CEC which fall into three distinct groups. These groups are those performed using capillaries packed with novel or unique stationary phases designed for CEC, and a smaller group where standard HPLC stationary phases packings such as ODS has been used. The third group involves the use of surface coated capillaries. This paper reviews the separation of acidic compounds by CEC and also includes a number of novel applications to illustrate the separation approaches and the analytical performance possible.

Acids↗

PubMed1998

Separation of a range of cations by nonaqueous capillary electrophoresis using indirect and direct detection.

The use of nonaqueous media and indirect detection is reported for the separation and detection of a range of small cations. The novel applications involved separation of a range of metal ions, small nonchromophoric amines, cationic ion-pair reagents and cationic surfactants. Separations were achieved using acidified methanol containing imidazole as the UV co-ion for indirect detection. The methods produced different selectivity compared to aqueous methods using acidified aqueous imidazole solutions. Advantages of the methods include speed of analysis and prevention of sample micellerisation. The methods were shown to be quantitative and reproducible by their application to the determination of Tris content.

Amines↗

PubMed1998

Optimisation, validation and application of a capillary electrophoresis method for the determination of ranitidine hydrochloride and related substances.

Ranitidine hydrochloride is an H2-antagonist which is widely prescribed for the treatment of peptic ulcers. The drug is marketed in a variety of dosage forms including tablets, syrups and injection solutions. A range of synthetic and degradative impurities of ranitidine are known and currently, these impurities are routinely determined using thin-layer chromatography (TLC). Alternatively a high-performance liquid chromatography (HPLC) method has also been employed in the assay of the pharmaceutical preparation. Unlike TLC, capillary electrophoresis (CE) offers the capability to quantify simultaneously both the active drug content and the levels of the related substances. The advantages of simplicity, selectivity, versatility and ease of use of CE offers a complementary separation technique to the established methods of HPLC and TLC in the determination of ranitidine and its related substances. This work represents a comprehensive evaluation of the performance of a developed CE method in the determination of drug-related impurities in both drug substance and various pharmaceutical formulations. The data obtained clearly shows that the performance of an optimised CE method can be equivalent in terms of sensitivity and precision to that of a HPLC method employed for a similar purpose and offers better selectivity against TLC and HPLC.

Chromatography, High Pressure Liquid↗

PubMed1998

The use of microemulsion electrokinetic chromatography in pharmaceutical analysis.

The use of a single set of microemulsion electrokinetic chromatography (MEEKC) separation conditions has been assessed for its applicability in the analysis of a range of pharmaceutical compounds. Particular emphasis was placed on neutral or very hydrophobic compounds, which can be difficult to analyse by conventional capillary electrophoresis. The microemulsion employed for the majority of separations consisted of 0.81% w/w octane, 6.61% w/w 1-butanol, 3.31% w/w sodium dodecyl sulphate and 89.27% w/w 10 mM sodium tetraborate buffer. Good separations of methyl, ethyl, butyl and propyl hydroxybenzoates, and a range of ionic and neutral water soluble and insoluble compounds was achieved using a single set of separation conditions. A number of novel applications of MEEKC were developed included the simultaneous determination of the active components and preservatives in liquid formulation and determination of drug related impurities. Improved performance was obtained through use of internal standards and preparation of the samples dissolved in the microemulsion solution. Validation aspects such as linearity, repeatability, accuracy, injection precision and sensitivity were successfully assessed.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed1998

Development and optimisation of a generic micellar electrokinetic capillary chromatography method to support analysis of a wide range of pharmaceuticals and excipients.

A micellar electrokinetic capillary chromatography (MECC) method has been developed and validated to allow the analysis of a wide range of water soluble and insoluble acidic, basic and neutral drugs and excipients. An electronic database has been established to demonstrate the wide applicability of the method. The method has been validated and is now in routine use. In particular, acceptable injection precision is obtained through use of internal standards. Optimal sensitivity was obtained by using low UV wavelength detection. The method allows a number of cost and time saving benefits.

Chromatography, Micellar Electrokinetic Capillary↗

PubMed1997

Rapid resolution of drugs and related substances with an eCAP polyamine coated capillary.

The long term stability of a commercial polyamine coated capillary (eCAP) is described. The capillary, which can be used in the CZE and MEKC mode, is based on coating with a polyamine after conditioning with 1 M NaOH and regeneration of this coating after each run. The stability was tested over 6 months on the drug trimethoprim and the R.S.D. values for migration time and peak area were 2.86 and 3.62% respectively (n = 8, each time of determination) (> 600 sample injections over the period). This stability was utilised in the validated method developed for trimethoprim and four of its related impurities. The repeatability of peak area for trimethoprim (without normalisation or external standard) was, within-day R.S.D. = 1.02% (n = 8) and between-days R.S.D. = 2.02% (n = 8 each day). Linearity was good (for 50 micrograms ml-1 target) (y = 249.6x + 17.3 (r = 0.992, n = 6). These results for trimethoprim and for other drug mixtures were comparison with conventional capillaries and the advantage of reducing the polyamine treated eCAP capillary to a minimum length is described, to achieve rapid assay of the 5 component timethoprim mixture in < 2 min.

Acyclovir↗

PubMed1997

Validated capillary electrophoresis method for the analysis of a range of acidic drugs and excipients.

A capillary electrophoresis (CE) method employing a high pH borate buffer has been validated to allow analysis of a wide range of acidic compounds including active drugs, pharmaceutical formulations, excipients, starting materials and intermediates. An internal database has been established to demonstrate the wide applicability of the method. The method has been extensively validated and is in routine use in a number of our laboratories worldwide. In particular, acceptable injection precision is obtained through the use of internal standards and the method robustness was evaluated using an experimental design. The method allows a number of cost and time saving benefits.

Acids↗

PubMed1996

Validated capillary electrophoretic method for the quantitative analysis of histamine acid phosphate and/or benzalkonium chloride.

A novel capillary electrophoresis method has been developed and validated for the quantitative determination of histamine acid phosphate (HAP) and/or benzalkonium chloride (BKC). The solutes were separated using a pH 2.5 phosphate electrolyte with detection at 200 nm. Acceptable precision was obtained using internal standardisation. The method was also acceptable for determining levels of histidine which is an impurity in HAP. Profiling of BKC homologues was demonstrated for batch identity purposes. This method is used routinely and it is intended to register this method in the British Pharmacopoeia to supplement current test methods of TLC and HPLC.

Anti-Infective Agents, Local↗

PubMed1996

Quantitative determination of tryptophan enantiomers by capillary electrophoresis.

A novel capillary electrophoretic method is reported which allows efficient detection of 0.1% L-tryptophan in the presence of the D-enantiomer. The optimised conditions employed a triethanolamine-phosphoric acid electrolyte containing alpha-cyclodextrin. The method is also capable of acceptable injection precision resulting from the incorporation of an internal standard. The care and maintenance of the separation capillary are discussed. Acceptable validation criteria for sensitivity, precision, linearity, repeatability and recovery are included. The importance of including instrument-to-instrument method transfer in method validation is stressed and demonstrated.

Cyclodextrins↗

PubMed1996

Determination of drug-related impurities by capillary electrophoresis.

The use of capillary electrophoresis (CE) to determine drug-related impurities is becoming established within industrial pharmaceutical analysis laboratories. Increasingly CE is being viewed as an alternative for, and complement to, high-performance liquid chromatography (HPLC). This paper comprehensively reviews the progress of CE in drug impurity determinations subdividing the reports into low pH, high pH and MECC applications. The section covering method performance and validation clearly shows that CE methods are capable of validation in this area and can often give equivalent performance to HPLC methods. Possible benefits of adopting CE for this testing include reductions in costs and improved robustness. Potential developments are covered including the use of electrolyte additives, instrumental developments and the increased implementation of electrochromatography. It is concluded that the current status of CE is sufficiently strong to allow the analyst to view CE as a viable and attractive alternative to HPLC.

Chemistry, Pharmaceutical↗

PubMed1996