Entity

Time filter

Source Type

Assen, Netherlands

Van De Merbel N.C.,Bioanalytical Laboratory | Van De Merbel N.C.,University of Groningen | De Vries R.,Janssen RandD
Bioanalysis | Year: 2013

Apart from the well-known matrix effects that can occur in ESI LC-MS, biological matrices may have other effects influencing the quantitative reliability of bioanalytical methods. In this paper, six case studies are presented that show the effect that aging, that is the change in properties and composition of biological matrices over time, can have on the performance of bioanalytical methods. It is shown that selectivity can be affected due to the formation or disappearance of endogenous compounds. Stability can be influenced because of the decrease (or increase) of enzyme activities and recovery can be impacted if the extractability from binding sites in the matrix is enhanced or decreased. A general discussion on the importance of these matrix effects is provided as well as a perspective on how to properly address them in the method-development and validation stages of regulated bioanalysis. © 2013 Future Science Ltd. Source


Van De Merbel N.,Bioanalytical Laboratory | Savoie N.,Algorithme Pharma Inc. | Yadav M.,Alkem Laboratories | Ohtsu Y.,Astellas Pharma Inc. | And 5 more authors.
AAPS Journal | Year: 2014

This paper provides a comprehensive overview of stability-related aspects of quantitative bioanalysis and recommends science-based best practices, covering small and large molecules as well as chromatographic and ligand-binding assays. It addresses general aspects, such as the use of reference values, transferability and treatment of failing stability results, and also focuses on specific types of stability assessment: bench-top, freeze/thaw and long-term frozen stability, stock stability, extract stability, stability in whole blood, tissue and urine, and stability of endogenous analytes, in special matrix types and in incurred samples. © 2014 American Association of Pharmaceutical Scientists. Source


Hilhorst M.,Bioanalytical Laboratory | Van Amsterdam P.,Abbott Laboratories | Heinig K.,Hoffmann-La Roche | Zwanziger E.,Hoffmann-La Roche | Abbott R.,Bayer AG
Bioanalysis | Year: 2015

In bioanalysis of small molecules, the analyte concentration in the measured samples should reflect the concentration during sample collection. Precautions may be needed to prevent over- or under-estimation of the obtained result. This might require the addition of stabilizers to prevent degradation or nonspecific binding. For unstable drugs, it is essential to know how analytes can be stabilized before the start of the clinical study. Although the stabilization methods are well documented, the impact of the stabilization on the clinical workflow is not properly addressed. Already during method development, the clinical implications in terms of personnel safety, ease of use, training possibilities and staff capacity should be taken into account, and validation of the bioanalytical method should reflect collection procedures. © 2015 Future Science Ltd. Source


Wilffert D.,University of Groningen | Reis C.R.,University of Groningen | Reis C.R.,Southwestern Medical Center | Hermans J.,University of Groningen | And 7 more authors.
Analytical Chemistry | Year: 2013

The major challenge in targeted protein quantification by LC-MS/MS in serum lies in the complexity of the biological matrix with regard to the wide diversity of proteins and their extremely large dynamic concentration range. In this study, an LC-MS/MS method was developed for the simultaneous quantification of the 60-kDa biopharmaceutical proteins recombinant human tumor necrosis factor-related apoptosis-inducing ligand wild type (rhTRAILWT) and its death receptor 4 (DR4)-specific variant rhTRAIL4C7 in human and mouse serum. Selective enrichment of TRAIL was accomplished by immobilized metal affinity chromatography (IMAC), which was followed by tryptic digestion of the enriched sample and quantification of a suitable signature peptide. For absolute quantification, 15N-metabolically labeled internal standards of rhTRAILWT and rhTRAIL4C7 were used. Since the signature peptides that provided the highest sensitivity and allowed discrimination between rhTRAILWT and rhTRAIL4C7 contained methionine residues, we oxidized these quantitatively to their sulfoxides by the addition of 0.25% (w/w) hydrogen peroxide. The final method has a lower limit of quantification of 20 ng/mL (ca. 350 pM) and was fully validated according to current international guidelines for bioanalysis. To show the applicability of the LC-MS/MS method for pharmacokinetic studies, we quantified rhTRAIL WT and rhTRAIL4C7 simultaneously in serum from mice injected intraperitoneally at a dose of 5 mg/kg for each protein. This is the first time that two variants of rhTRAIL differing by only a few amino acids have been analyzed simultaneously in serum, an approach that is not possible by conventional enzyme-linked immuno-sorbent assay (ELISA) analysis. © 2013 American Chemical Society. Source


Pihl S.,Lundbeck | Michaut L.,Novartis | Hendriks J.,Crucell | Loebbert R.,AbbVie Deutschland GmbH and Co. KG | And 4 more authors.
Bioanalysis | Year: 2014

Long- and short-term stability testing of the analyte is one of the key parameters in bioanalytical method validation in support of pharmacokinetics. However, for immunogenicity testing, the scientific rationale for long- and short-term stability testing on quality control samples most often spiked with polyclonal antibody raised in a different species should be questioned. Therefore, the European Bioanalysis Forum (EBF) formed a Topic Team to discuss the scientific rationale for stability testing of anti-drug antibodies (ADAs). A review of EBF member companies' experience on ADA stability and on anti-vaccine antibodies from vaccine projects was the basis of this discussion. EBF recommends to perform short-term stability testing of the positive control, but not to perform long-term stability testing of ADAs in nonclinical and clinical studies. © 2014 Future Science Ltd. Source

Discover hidden collaborations