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A biomarker is measured as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to therapeutic intervention. Many times, a putative biomarker is a protein or peptide that is expressed at a relatively low level compared to the surrounding proteome. The constitutive or housekeeping proteins are present in concentrations that are orders of magnitude above the protein of interest, which makes identification and quantitation difficult. In order to validate a candidate biomarker, many samples need to be analyzed to prove that the same analytes are reproducibly identified and are changing in a statistically significant manner due to a perturbation.

Since the introduction of the Waters® ACQUITY UPLC® System, many vendors have introduced modified high-performance liquid chromatography (HPLC) systems designed for fast LC or ultra-high-pressure liquid chromatography (UHPLC). These systems, which can yield satisfactory chromatography at an analytical scale (4.6-mm I.D.), where system volume and system bandspread have less of an impact on peak width, struggle significantly with microbore chromatography (2.1-mm I.D.). These low-volume separations require a system designed to maximize the separation efficiency to provide greater quality information for the user.

During the manufacture of active pharmaceutical ingredients (APIs), the formulation of drug substances, and therapeutic fill and finish, the removal of residues from manufacturing equipment is performed by a series of cleaning procedures. It is imperative that the production equipment be properly cleaned in order to avoid cross-contamination of drug products.1-3 The efficiency of the cleaning procedures must be demonstrated through cleaning validation. This involves demonstrating that residual API, starting material, intermediates, and impurities have been removed from the production equipment.

News All the news from September 2005 Opinion Zosimus provides a controversial look at the trend of selecting monolithic columns and asks if they are all that they are cracked up to be. Benefits of the pretreatment step in purifying water for the LC-MS analyses Two specialists from Millipore provide their discoveries on this subject. Country focus The growing importance of the Chinese analytical science market is the focus this month. Q&A Damian Morrison from Waters speaks to The Column about its BEH technology and how it marks a new milestone in chromatography. Supplies & services

Millipore Corporation (Billerica, Massachusetts) announced that it recently has acquired over 90% of NovAseptic AB (Gothenburg, Sweden) shares. Millipore is in the process of acquiring the remaining shares from the minority shareholders.

J. Peterson, S. henderson, and B. Richter, Dionex Corporation

This article gives an overview of screening methods for the detection of antimicrobials, including dilution and diffusion methods and bioautography, mainly direct bioautography. The thin-layer chromatography method with direct bioautography was worked out to analyse enrofloxacin and ciprofloxacin residues in milk.

Where the wizard stands behind the curtain working levers.

This article looks at the use of electromigration techniques to determine microorganisms, such as viruses, bacteria and other biologically important macromolecules (erythrocytes), in medical analyses. It was found that electromigration techniques could be used for the identification of several viruses, including the identification of a specific marker for the Hepatitis C virus infection and another for a urinary tract infection. The determination of cell viability and the quality control of probiotics and consumer products that contain active bacteria is also possible using electromigration. Special attention is paid to the modification of capillary wall surfaces using different monomers and the application of monolithic columns to determine active bacteria in pharmaceutical products using capillary electrochromatography (CEC) conditions. This approach represents a new frontier for separation science and the possibility to apply it in medical diagnosis.

Emerald expansion