Aim: Very long chain fatty acids (VLCFAs) have been identified as biomarkers for several peroxisomal disorders necessitating the need for reliable biomarker assays in particular C20, C22, C24, C26 in cerebrospinal fluid (CSF). Until now no absolute quantitation assay for total VLCFAs in CSF has been successfully developed and qualified for clinical use. Methodology: A […]
Aim: The metabolism of tryptophan (TRP) through kynurenine (KYN) and 5-hydroxytryptamine (5-HT) pathways is linked to various diseases such as neurological diseases and cancer. The levels of 5-HT, KYN, TRP can be used as indicators for the diagnosis of various diseases in clinical and scientific research. Experimental: Since 5-HT, KYN, TRP are all endogenous molecules
Pharmacokinetics (PK) is the branch of pharmacology dedicated to determining the fate of substances in the body. PK assays are, therefore, an essential element in the development of new drugs, with favorable PK profiles essential to promising leads progressing to the later stages of development. In combination with pharmacodynamic (PD) assays, PK assays are vital
Aim: Developing LC–MS methods for biomolecules is often challenging due to issues with molecular size and complexity, nonspecific binding, protein binding, solubility and sensitivity. As a result, complex sample preparation workflows, including immune-affinity and/or protein digestion and lengthy analysis potentially using nano-flow LC, may be needed to achieve the required sensitivity. This work aims to
Aim: Microflow tandem mass spectrometry-based methods have been proposed as options to improve sensitivity and selectivity while improving sample utility and solvent consumption. Here, we evaluate a newly introduced microflow source, OptiFlow™, for quantitative performance. Results/methodology: We performed a comparison of the OptiFlow and IonDrive™ sources, respectively, on the same triple quadrupole mass spectrometer. The
Aim: A sensitive and reliable LC–MS/MS method has been established and validated to the quantitation of rivaroxaban (RIV) and TAK-438 in rat plasma using carbamazepine as internal standard. Results: The procedure of method validation was conducted according to the guidelines of EMA and US FDA. At the same time, the method was applied to pharmacokinetic
Welcome to volume 12 of Bioanalysis. We want to take this opportunity to wish you all a Happy New Year. As we step into another year of the journal, we would like to reflect on the last year, which was an important milestone for the journal having reached its tenth anniversary. We want to thank
Aim: ZY-19489 is a new antimalarial drug candidate and selective LC–MS/MS method was established for estimation of ZY-19489 and its metabolite in human plasma. Materials & methods: LLE was employed for extraction, mass spectrometric quantification performed using positive ionization mode and DCP-IMP was used as an internal standard. The chromatographic separation was achieved using mobile
Aim: IL-33 is a potential therapeutic target but commercially available assays for the quantitation of systemic IL-33 have poor reliability. Results: In commercial IL-33 kits, interference from endogenous binding partners (e.g., soluble ST2) causes under-quantitation. Mitigating this required acid dissociation and addition of the detection reagent simultaneously with the capture step. This enabled detection of
Aim: To compare the difference between the measured and target values in vancomycin external quality assessment (EQA) samples and to investigate the factors for underestimating its concentration. Materials & methods: A retrospective analysis of 195 international vancomycin EQA results was performed. Deviations of the concentrations determined by TDx fluorescence polarization immunoassay (FPIA), Axsym FPIA and