Biomedical subjects

William Bowen

Publications and source records attributed to William Bowen.

3 recordsLinked to original sources

PubMed2005

"Orthogonal" separations for reversed-phase liquid chromatography.

A general procedure is proposed for the rapid development of a reversed-phase liquid chromatographic (RP-LC) separation that is "orthogonal" to a pre-existing ("primary") method for the RP-LC separation of a given sample. The procedure involves a change of the mobile-phase organic solvent (B-solvent), the replacement of the primary column by one of very different selectivity, and (only if necessary) a change in mobile phase pH or the use of a third column. Following the selection of the "orthogonal" B-solvent, column and mobile phase pH, further optimization of peak spacing and resolution can be achieved by varying separation temperature and either isocratic %B or gradient time. The relative "orthogonality" of the primary and "orthogonal" RP-LC methods is then evaluated from plots of retention for one method versus the other. The present procedure was used to develop "orthogonal" methods for nine routine RP-LC methods from six pharmaceutical analysis laboratories. The relative success of this approach can be judged from the results reported here.

Chromatography, Liquid↗

PubMed2003

Spectroscopic approach for on-line monitoring of particle size during the processing of pharmaceutical nanoparticles.

A novel application of near-infrared (near-IR) spectroscopy for the on-line determination of nanoparticle size of a drug compound in a high solids dispersion is described. The on-line spectroscopic technique provides real-time data for process monitoring and control and overcomes the limitations that are encountered using laboratory-based instrumentation for nanoparticle size determination. Near-IR spectroscopy is capable of providing an accuracy of 2.4 nm near the endpoint of particle production, where the volume-weighted D90 particle size is determined to be 200-220 nm. The accuracy is adequate for endpoint control, which minimizes excess processing and provides control over the particle size throughout nanoparticle production.

Drug Compounding↗

PubMed2002

An analytical review of environmental justice research: what do we really know?

This article presents a review of major empirical research on environmental justice. Forty-two empirical research studies spanning three decades were evaluated and categorized on the basis of how well they meet reasonable scientific standards. Twelve of those studies are described and critiqued in detail, and an overview of trends in the literature is presented. The author concludes that the empirical foundations of environmental justice are so underdeveloped that little can be said with scientific authority regarding the existence of geographical patterns of disproportionate distributions and their health effects on minority, low-income, and other disadvantaged communities. If environmental managers and policy-makers do not recognize the high levels of empirical uncertainty surrounding the issue, they are apt to attribute an empirically unwarranted level of concreteness to the empirical research findings, thus leading to poorly conceptualized and therefore potentially harmful policy and management decisions.

Conservation of Natural Resources↗