Pharmaceutical Analysis

Basic information on stereochemistry is provided in this article to help readers develop a better understanding of the separation mechanisms that come into play in various separation methods used for chiral compounds. This knowledge can allow readers to select a desirable chiral separation method, based upon the molecular structure of the chiral compound of interest. Logical reasons for the selection process are discussed later in this article.

An ultrahigh-pressure liquid chromatography (UHPLC) method was developed to separate paroxetine from several of its related compounds using a systematic screening protocol that monitors combinations of selectivity factors including column chemistry, organic modifier, and pH. When the best combination of these factors was selected, the method was optimized by varying gradient slope and temperature.

HPLC 2007 was held in Ghent, Belgium in June. Last month, columnist Ron Majors summarized some the important column developments as well as other Symposium highlights. This month, he winds up coverage with additional highlights in the areas of technology and applications. Among the topics covered are stationary phase preparation and characterization, multi-dimensional and comprehensive LC, temperature studies, detectors and an application overview.

The Green Chemistry Group, a non-profit organization dedicated to promoting the benefits of environmentally-friendly research and development processes, will host the 1st International Conference on Supercritical Fluid Chromatography (SFC) September 23-25, 2007 at the Sheraton Station Square Hotel in Pittsburgh, Pennsylvania.

Leipziger Messe, organisers of L.A.B. - the trade fair and conference devoted to analysis, bio and laboratory equipment - have announced that the show will host 88 exhibitors from countries including the UK, US, France, Italy, Finland, the Netherlands, and Germany. L.A.B. takes place from 2-4 October 2007 at ExCeL London.

Waters Corporation (Milford, Massachusetts) and Lambda Therapeutic Research Ltd (Mumbai, India) recently announced a joint cooperative agreement that provides innovative analytical laboratory equipment designed to enhance research quality service and business solutions for Lambda and its clients.

Science Daily, a website that features news revolving around the sciences, has published an article that describes new chromatographic techniques for the analysis of pesticides and antibiotics in food and beverage samples.

Nanostream, provider of products and services that increase productivity in laboratories at pharmaceutical and biotech companies, extends its global reach to Europe by establishing a sales and support office in The Netherlands.

The effect of switching between high and low pH mobile phases on a single analytical HPLC column was investigated. The ability to rapidly switch between pH extremes on XBridge columns without special washing/re-equilibration steps dramatically reduces the time for separation of pharmaceutical compounds.

Cleaning validation is a major analytical application in the pharmaceutical industry. Here, high performance liquid chromatography (HPLC) with charged aerosol detection is compared and contrasted to HPLC with UV detection showing comparable performance and several advantages for charged aerosol detection, especially for analytes that do not contain a chromophore.

Phenomenex, Inc., a global leader in the separation sciences business, has been notified by R&D Magazine that it has won the coveted R&D 100 Award for the second year in a row.

This article describes the use of ultrahigh-pressure liquid chromatography (UHPLC) in pharmaceutical analysis of drug substances and drug products with UV absorption detection.

Mass overload is related to the mass of sample that can be injected before the stationary phase is sufficiently loaded to cause changes in the chromatography.

The concept of membrane-controlled processes is widespread in nature. Nearly all biological mechanisms concerning mass transport and exchange are regulated by membrane barriers and a variety of technical and biotechnological applications have been devised based on this mechanism. Membrane applications in analytical chemistry are geared towards the enrichment of target substances from an aqueous solution or the separation of compounds from a complex matrix. This article describes membrane-assisted extraction processes to separate traces of polar pharmaceutical substances the so called emerging micropollutants from aqueous samples. Basic prospects and examples of membrane-supported extractions are presented.

Mixed mode chromatography combines aspects of ion exchange chromatography and conventional reversed-phase (RP) chromatography. The combination of both hydrophobic and ion-exchange properties allows for independent control of retention for ionizable and neutral molecules.

Detector selection for a method should be made on a case-by-case basis.

LC-MS-MS has become a widely used technique for the fast and sensitive quantitation of small molecules. In this article, this approach has been extended to high-throughput quantitative LC-MS-MS analysis under GLP applications for a drug candidate in development from preclinical animal studies through clinical development.

Bob Wiedemer, Grace Davison Discovery Sciences

Xiaodong Liu and Christopher Pohl, Dionex Corporation

Eric S. Grumbach, Diane M. Diehl and Jeffrey R. Mazzeo, Waters Corporation

Fast, reliable measurements of lipophilicity has a great impact on the compounds' selection process at an early stage of dug discovery. The guest columnit examines HPLC methods for this purpose.

Separation instrument techniques are among the most widely used technologies in the analytical instrumentation market. They span the entire industrial and regional marketplace. The lab separations market includes chromatographic techniques such as analytical and preparative HPLC, GC, IC, TLC, flash, and low pressure LC.

In the mid 1980s the chromatographic application of gases compressed (or liquefied) to supercritical state was tested by research teams from several analytical instrument manufacturers. The recently introduced capillary columns seemed ideal candidates on which to perform such supercritical fluid chromatography (SFC) methods.

A reluctance to make any changes to a validated or compendial method is common, and often well founded.

Excess variability is not acceptable in a pharmaceutical method.