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Petaluma, CA, United States

Golden R.,ToxLogic LLC | Valentini M.,Analytical science
Regulatory Toxicology and Pharmacology | Year: 2014

Due largely to the controversy concerning the potential human health effects from exposure to formaldehyde gas in conjunction with the misunderstanding of the well-established equilibrium relationship with its hydrated reaction product, methylene glycol, the concept of chemical equivalence between these two distinctly different chemicals has been adopted by regulatory authorities. Chemical equivalence implies not only that any concentration of methylene glycol under some condition of use would be nearly or completely converted into formaldehyde gas, but also that these two substances would be toxicologically equivalent as well. A relatively simple worst case experiment using 37% formalin (i.e., concentrated methylene glycol) dispels the concept of chemical equivalence and a review of relevant literature demonstrates that methylene glycol has no inherent toxicity apart from whatever concentration of formaldehyde that might be present in equilibrium with such solutions. © 2014 Elsevier Inc. Source


Shi Y.,Taiyuan Normal University | Li Z.,Taiyuan Normal University | Qiao Y.,China Pharmaceutical University | Lin J.,Analytical science
Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences | Year: 2012

This work aimed to develop a rapid capillary zone electrophoresis (CZE) method to provide abundant purity and identity information of monoclonal antibodies. The CZE running buffer system was optimized to be 20. mM acetate-acetic acid (pH 6.0) together with the co-addition of 0.3% polyethylene oxide (PEO) and 2. mM triethylenetetramine (TETA), which was further tested with advantages on the peak resolution improvements. The conditioning period was scheduled to 1. min for both 0.1. M HCl and CZE running buffer to reduce total separation time. Additionally, the applied voltage and effective separation length were optimized at 30. kV and 20. cm separately. Compared with the method reported by Yan [1], this newly developed method showed a higher resolution in separating the two unknown basic peaks by testing monoclonal antibody sample (mAb1). The further validation results showed that for all five of charge isoform peaks of test mAb1, repeatability, intraday and interday precision had a RSD less than 0.58% for migration time and less than 3.18% for corrected area percent. The correlation coefficients of more than 0.98 for all peaks also demonstrated the good linearity for the method. In addition to the application of distinguishing intact antibody from C-terminal Lys variants, the method also has advantage in separating the Fab, Fc and intact antibody-relevant substances quickly, which facilitated the rough evaluation of papain induced digestion. © 2012 Elsevier B.V. Source


Noble J.E.,Analytical science
Methods in Enzymology | Year: 2014

The measurement of a solubilized protein concentration in solution is an important assay in biochemistry research and development labs for applications ranging from enzymatic studies to providing data for biopharmaceutical lot release. Spectrophotometric protein quantification assays are methods that use UV and visible spectroscopy to rapidly determine the concentration of protein, relative to a standard, or using an assigned extinction coefficient. Where multiple samples need measurement, and/or the sample volume and concentration is limited, preparations of the Coomassie dye commonly known as the Bradford assay can be used. © 2014 Elsevier Inc. All rights reserved. Source


News Article
Site: http://www.nature.com/nature/current_issue/

Citizen scientists are an underrated source of observations on medical conditions. They frequently offer researchers a head start in the hunt for biomarkers (see, for example, the tentative identification of volatile indicators of early Parkinson's disease: go.nature.com/wggoss). The precision and high-throughput capability of analytical technology drives most advances in clinical diagnostics ( et al. Nature 502, 317–320; 2013). Analytical science and its subdiscipline metabolomics (the study of chemical fingerprints left by cellular processes) are also crucial for guiding clinical decisions (see go.nature.com/l8pcde). These tools are set to be valuable for investigating and tapping into citizen scientists' previously unreported medical phenomena.


Worsley G.J.,Analytical science | Worsley G.J.,DNA Electronics Ltd | Kumarswami N.,Analytical science | Minelli C.,Analytical science | Noble J.E.,Analytical science
Analytical Methods | Year: 2015

The batch-to-batch assay performance 'activity' of antibody conjugated particles is often variable, leading to poor reproducibility between different production batches. We therefore sought to quantify the properties of such particles using differential centrifugal sedimentation (DCS) to see how they influence assay performance, with the aim to improve the reproducibility of the conjugation reaction. The DCS high resolution size distributions of the antibody conjugated particles allowed us to examine the thickness of the antibody corona on the particles and to quantify the amount of 'contaminating' particle oligomers produced via carbodiimide chemistry. The DCS data was correlated with the assay response of the resulting conjugate using an interleukin 6 (IL6) lateral flow assay developed in house. We prepared a series of antibody conjugates using various carbodiimide reaction conditions and analysed the size, antibody corona and oligomerisation profile of the resulting particles using both dynamic light scattering (DLS) and DCS. Both the amount of antibody bound to the particle and the presence of higher order particle oligomers produced conjugates that when applied in an IL6 lateral flow assay were associated with an enhanced fluorescent signal. Both the amount of particle oligomers and antibody bound to the particle was found to be positively correlated with increased assay response in the lateral flow. The DCS estimation of protein corona thickness for each carbodiimide condition tested was found to correlate with the amount of antibody coupled to the particles, as assessed using the bicinchoninic acid (BCA) assay. We have shown the novel application of DCS for the analysis of antibody-particle conjugates. DCS analysis provides a quantitative method to characterise particles and provides a rationale for variable assay performance observed from batch-to-batch production. © 2015 The Royal Society of Chemistry. Source

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