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Biomedical subjects

D Mallett

Publications and source records attributed to D Mallett.

4 recordsLinked to original sources
PubMed2001

Direct analysis of pharmaceutical compounds in human plasma with chromatographic resolution using an alkyl-bonded silica rod column.

Monolithic columns have been successfully used with steep gradient and high flow rates for the direct analysis of a candidate pharmaceutical compound in human plasma. The monolithic columns showed excellent robustness with nearly 300 20-microL injections of plasma (diluted 1:1 with water) being made onto one column without significant deterioration in performance. The system gave excellent sensitivity with a limit of quantification of 5 ng/mL being achieved. Unlike previous methods of direct analysis the monolithic columns showed excellent resolution even after nearly 300 plasma injections. The column performance was measured before and after the analysis of the plasma samples.

Chromatography, Gel↗
PubMed1999

The application of fast gradient capillary liquid chromatography/mass spectrometry to the analysis of pharmaceuticals in biofluids.

Fast gradient capillary high performance liquid chromatography (HPLC) coupled to a mass spectrometer has been successfully used for the analysis of pharmaceutical compounds from biological matrices, in the femtogram on column range. In the work reported in this paper, the use of capillary HPLC, on the 180-micron internal diameter scale, has shown a 30-fold improvement in detection limits when compared to conventional 2-mm scale chromatography. The use of fast gradient elution resulted in a generic methodology which gave excellent chromatographic reproducibility and column longevity. This technique has been used in conjunction with simple protein precipitation, with no deleterious effect on either the column life or the chromatographic performance. The use of capillary HPLC in bioanalysis has the potential to give a significant increase in assay sensitivity with the equipment currently in use. In this paper the authors also present a modification to the current PE-Sciex ion-spray source which allows excellent spray adjustment in three dimensional accessibility, which is important when working with low flow rates, as well as reducing the inherent system dead volume.

Body Fluids↗
PubMed1998

Application of a generic fast gradient liquid chromatography tandem mass spectrometry method for the analysis of cytochrome P450 probe substrates.

A liquid chromatography tandem mass spectrometry (LC/MS/MS) method has been developed for the fast routine analysis of selected CYP450 probe substrate metabolites in microsomal incubations, with no sample pretreatment. This has allowed fast and simple assessment of the potential effects which drug candidates may or may not have on the metabolism of specific CYP450 probe substrates, providing information which can then be used to rationalize in vivo interaction studies required in the clinic. This methodology takes advantage of fast gradient chromatography as a generic means of sample separation and analysis. It provides high throughput analysis compared to conventional gradient HPLC, with no significant loss in chromatographic performance.

Chromatography, Liquid↗