Aim: The purpose of this work was to develop and validate a rapid and robust LC–MS/MS method for the determination of dexmedetomidine (DEX) in plasma, suitable for analysis of a large number of samples. Method: Systematic approach, Design of Experiments, was applied to optimize ESI source parameters and to evaluate method robustness, therefore, a rapid, […]
Aim: Volumetric absorptive microsampler (VAMS) was designed to sample a fixed volume of blood regardless of the hematocrit (HCT) levels. Model compounds with a wide range of hydrophobicity were evaluated for their extraction recoveries from VAMS dried blood samples. Results: For the highly hydrophobic compounds, recoveries with methanol or methanol/acetonitrile extraction were higher compared with
Aim: Hepcidin, the main iron metabolism regulator, can be detected in various biological fluids. Here, we describe a quantitative method of LC–MS/MS to quantify the 25 amino acid isoform of hepcidin (hepcidin-25) in human cerebrospinal fluid (CSF). Results & methodology: Samples were prepared through protein precipitation followed by solid phase extraction (SPE) and injected into
Daniel Tang talks to Sankeetha Nadarajah, Commissioning Editor (Bioanalysis), regarding the China Bioanalysis Forum (CBF), in which Daniel was one of the co-founders and remains as its co-chair. Daniel is currently the CEO of UP Pharma, a biologics focused bioanalytical CRO in China. Keywords:
Protein aggregation is a common biological phenomenon which is responsible for degenerative diseases and is problematic in the pharmaceutical industry. According to the rules provided by regulatory agencies, industry is supposed to assess the product quality regarding the presence of subvisible particles. Also, they should evaluate the technologies that are used to measure these particles.
Aim: Midazolam is a commonly used marker substrate for the in vivo assessment of CYP3A activity. Reliable pharmacokinetic assessment at sub-pharmacological doses of midazolam requires an ultra-sensitive analytical method. Methods: A new, ultra-sensitive LC–MS/MS method for the determination of midazolam in human plasma using SPE was developed and fully validated. The lowest limit of quantitation
Aim: An HPLC method for the determination of 2-hydroxyfluorene (2-OHF), various hydroxyphenanthrene metabolites (1-, 2-, 3-, 4- and 9-hydroxyphenanthrene, OHPhs), 1-hydroxypyrene (1-OHPy) and 3-hydroxybenzo[a]pyrene (3-OHB[a]Py) in human urine, has been developed using fast scanning fluorimetric detection and gradient elution mode. Materials & methods: All reagents were of analytical grade. Standard solutions were prepared separately, by
Aim: Immobilized metal ion affinity chromatography is widely employed for purifying polyhistidine-tagged recombinant proteins from cell lysates. The technique can be applied for quantification of therapeutic proteins in biological matrices by LC–MS/MS. Results: A protein reagent-free workflow was developed for quantifying polyhistidine-tagged proteins by LC–MS/MS. The workflow includes target protein enrichment by immobilized metal ion
Aim: In metabolomics research, the use of different blood collection methods may influence endogenous metabolites. Materials & methods: Ultra HPLC coupled with MS/MS was applied together with multivariate statistics to investigate metabolomics differences in serum and plasma samples handled by different anticoagulants. A total of 135 known representative metabolites were assessed for comprehensive evaluation of
Figure 1. Schematic method development narrative. Vertical lines indicate iterations of and changes to the assay procedure. The magenta line corresponds to the method BT. BT: Breakthrough; EP: Exploratory phase; MV: Method validations; OP: Optimization phase; PV: Pre-validation phase. First draft submitted: 13 November 2016; Accepted for publication: 30 November 2016; Published online: 13 January