Pharmaceutical Analysis

Very short columns filled with 1.9 µm particles were evaluated for the ultra-fast analysis of pharmaceutical formulations. Local anæsthetic, mydriatic and anti-hypertensive agents were chosen as analytes and a method was developed and validated for each of these substances, according to ICH guidelines. Excellent quantitative performance was obtained using an optimized chromatographic system that reduces the importance of extra-column effects and cuts the analysis time to less than 15 s.

The regulatory world and associated guidance documents within the pharmaceutical industry is changing rapidly. This column gives an overview of what's happened since the start of the year.

Ramipril impurities D and E are well-known degradation products of ramipril in the finished dosage form. A significant amount of an additional impurity was detected in ramipril tablets by an isocratic reversed-phase high performance liquid chromatography (HPLC) method on a short column. The structure of this impurity was proposed based on liquid chromatography–mass spectrometry (LC–MS) data using an electron spray ionization source. Structural elucidation using nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy was facilitated by a newly developed preparative isolation method. This impurity was characterized as (2R,3aR,6aR)-1-[(R)-2-[[(R)-1-(ethoxycarbonyl)-3-phenylpropyl]amino]propanoyl]octahydrocyclopenta[b]pyrrole-2-carboxylic acid (impurity L). Its identification, synthesis and characterization are discussed.

Automated solid-phase extraction (SPE) has been used extensively with liquid chromatography–tandem mass spectrometry (LC–MS-MS) to facilitate high-throughput analysis in the pharmaceutical, diagnostic, and forensic toxicology areas. In this work, we demonstrate the use of a systemized approach to SPE method development and LC–MS-MS analysis. This approach provides dramatic savings in analysis time and takes advantage of new innovations in high performance liquid chromatography (HPLC) columns to provide the cleanest extracts for LC–MS injection.

The authors meet the need for a method for the determination of cytosine purity by developing a hydrophilic interaction chromatography (HILIC) method with demonstrated advantages in comparison to other separation techniques.

This article describes the ability to increase the sensitivity for a target compound in the presence of high-level background impurities by removing the dosing vehicle using a high-field asymmetric waveform ion mobility spectrometry gas-phase separation before mass spectrometry analysis.

The authors present results that suggest that high-throughput, high-coverage profiling capabilities, such as those afforded by GCxGC-TOF-MS, can impact the development of personalized medicine.

This month's column discusses the practicalities of detecting substitutions in counterfeit pharmaceuticals. The approaches used are practical "take home" lessons readers can apply to analyse unknowns in any mixture.

This month's "Validation Viewpoint" installment highlights some method validation guidelines used in developing and validating dissolution test procedures.

This month, guest columnists Kind and Fiehn discuss small-molecule structure elucidation (excluding peptides) using hyphenated chromatographic techniques, mass spectrometers, and other spectroscopic detectors.

This article describes the factors that affect the selection of columns for two-dimensional (2D) LCxLC separations.

Comprehensive GCxGC was employed for the separation of ICH and USP 1, 2, and 3 pharmaceutical solvents. The significantly improved peak capacity in GCxGC allows a single method for any combination of solvents and mitigates interference due to impurities in the solvents, diluents, analyte matrices, and from column or septum bleed, through the increased separation space.

This installment of "Validation Viewpoint" column addresses, in the hopes of clarifying what the biopharmaceutical industry is required to do today to identify and quantify impurities in their biotech, proteinaceous products.

In this month?s installment, columnist Ron Majors covers the field of immunoextraction, a technique that employs immobilized antibodies to selectively capture specific analytes using molecular recognition via antibody?antigen interactions. Recently, the introduction of commercial products for specific high-volume environmental and food safety applications has spurred further applications of this technique.

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.