Jun 9, 2009
By:Xiaodong Liu, Christopher Pohl, Dionex Corporation
Salt formation is a critical aspect in drug development (1) and HPLC is an important tool for determination of pharmaceutical counterions. Reversed-phase columns often fail to retain very hydrophilic counterions. Ion chromatography (IC) is preferred for selective and sensitive screening of cationic and anionic pharmaceutical counterions (2), usually with multiple runs. Positive and negative counterions can be separated simultaneously using a zwitterionic HILIC column using an evaporative light scattering detector (3). However, the zwitterionic column method has limitations: 1) limited to HILIC mode; 2) ions are retained as salts rather than via ion-exchange, making method development difficult; and 3) the method is not suitable for simultaneous separation of acidic, basic, and neutral analytes.
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Jun 9, 2009
By:Atis Chakrabarti, Tosoh Bioscience LLC
Since the USA Patriot Act* has been enacted, many pharmaceutical companies have reformulated their over the counter (OTC) drug products with phenylephrine (a nasal decongestant) as a substitute for pseudoephedrine. Phenylephrine comes as a tablet, a liquid, or a dissolving strip to take orally — all as a treatment for cold symptoms (1). Besides phenylephrine, most pharmaceutical formulations for common cold and sinus medications often contain multiple active ingredients to treat different types of symptoms in addition to numerous excipients. From an analytical perspective, the challenge is to develop chromatographic conditions that allow quantitative analysis of a variety of excipients that vary widely in hydrophobic properties.
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May 29, 2009
The particle design and bonding chemistry of TSK-GEL BioAssist S and BioAssist Q columns make them suitable for the high efficiency analysis of monoclonal antibodies at pH 6.0 by cation exchange or at pH 8.0 by anion exchange chromatography.
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May 29, 2009
This note provides an initial investigation concerning the stability of the TSKgel SuperSW3000 column under standard operating conditions. TSK-GEL SuperSW3000 columns are stable under typical SEC conditions used for the analysis of proteins. High column efficiency is maintained by protecting the analytical column with a short guard column and by periodic guard column replacement.
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May 29, 2009
During a method re-qualification at Lexigen Pharmaceuticals, several variables were investigated to eliminate non-specific binding and increase the robustness of an established antibody separation method. The selection of sodium perchlorate as a mobile phase component substantially improved the analysis and quantification of an experimental monoclonal antibody and its aggregates using a TSKgel SuperSW3000 column, thus providing the required level of method robustness.
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May 29, 2009
The TSKgel DNA-NPR column provides excellent chromatography and superior durability against the harsh HPLC method conditions required for oligonucleotide separations. Good separation of the protecting groups and impurity analogs from the 13-mer oligonucleotide product peak were demonstrated.
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May 29, 2009
Unlike single chain antibodies, IgM cannot be purified by Protein A (an affinity material commonly used for it's high binding capacity and excellent selectivity for antibodies) due to steric hindrance. The macroporous TSK-GEL BioAssist S offers high binding capacity and excellent resolution for purification of antibodies.
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Oct 13, 2008
By:Friedhelm Gores, PSS Polymer Standard Service, Inc.
Under the REACH (Registration, Evaluation and Authorisation of Chemicals) Regulations (EG) No. 1907/2006 the producer, manufacturer or importer of chemical substances / formulations have to register their products ( more than 1 ton/year) at the chemical agency. The preferred method to identify whether a substance falls under the definition of a polymer is Gel Permeation Chromatography (GPC). Guidelines on the determination of the molecular weight distribution using GPC are available in the OECD TG118 (1996).
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