Tuning selectivity in cation-exchange chromatography applied for monoclonal antibody separations, part 1: alternative mobile phases and fine tuning of the separation
Publication date: Available online 19 February 2019Source: Journal of Pharmaceutical and Biomedical AnalysisAuthor(s): Evelin Farsang, Amarande Murisier, Krisztián Horváth, Alain Beck, Róbert Kormány, Davy Guillarme, Szabolcs FeketeAbstractCation exchange chromatography (CEX) of therapeutic monoclonal antibodies is generally performed with either salt gradient (MES buffer + NaCl) or using commercial pH gradient buffer. The goal of this study was to find out some alternative buffer systems for CEX separation of mAbs, which may offer alternative selectivity, while maintaining similar peak shapes. Among the new buffers that were tested, (N-morpholino)ethanesulfonic acid (MES) / 1,3-diamino-2-propanol (DAP), and citric acid / 2-(cyclohexylamino)ethanesulfonic acid (CHES) systems were particularly promising, especially when combining them with a moderate salt gradient of NaCl. This two buffer system provides an equivalent or slightly better separation than the standard, mobile phases for therapeutic mAbs.It was also demonstrated that working with salt-mediated pH gradients, allows to extend the possibilities in method development, since the concentration of salt in the mobile phase has a significant impact on selectivity. Using HPLC modeling software (Drylab), it was possible to successfully develop CEX methods for authentic mAb samples within only 6 hours, by optimizing the gradient steepness and salt concentration in the B eluent.
Publication date: Available online 20 November 2019Source: Journal of Advanced ResearchAuthor(s): Sohail Mumtaz, Pradeep Bhartiya, Neha Kaushik, Manish Adhikari, Pradeep Lamichhane, Su-Jae Lee, Nagendra Kumar Kaushik, Eun Ha ChoiAbstractOver the past few decades, microwave (MW) radiation has been widely used, and its biological effects have been extensively investigated. However, the effect of MW radiation on human skin biology is not well understood. We study the effects of pulsed high-power microwaves (HPMs) on melanoma (G361 and SK-Mel-31) and normal human dermal fibroblast (NHDF) cells. A pulsed power generator (Chundo...
Passive measles immunity waned quickly, and most infants were no longer protected from measles by age 3 months, a study found; US experts say the age of vaccination should remain the same.Medscape Medical News
Suresh K. Mukherji
SURESH K. MUKHERJI, MD, MBA, FACR
NEUROIMAGING CLINICS OF NORTH AMERICA
Resting state functional connectivity (RSFC) has been widely studied in functional magnetic resonance imaging (fMRI) and is observed by a significant temporal correlation of spontaneous low-frequency signal fluctuations (SLFs) both within and across hemispheres during rest. Different hypotheses of RSFC include the biophysical origin hypothesis and cognitive origin hypothesis, which show that the role of SLFs and RSFC is still not completely understood. Furthermore, RSFC and age studies have shown an “age-related compensation” phenomenon. RSFC data analysis methods include time domain analysis, seed-based correl...
ConclusionLL/MLD4, MLA, MLD, the degree of luminal diameter stenosis, CCO, RI, and %APV derived from cCTA can support the detection of hemodynamically significant coronary stenosis as compared with iFR®, with LL/MLD4 showing the greatest discriminatory power.