Aim: Investigation of bile acids (BAs) as biomarkers for liver and kidney diseases has gained momentum recently to fulfill the needs in drug development and clinical practice, but a thorough and rapid profiling of BAs in human plasma has been hindered by the large interindividual variability and lack of selective methods. Results: A selective and […]
Biomarker ligand-binding assays need to be validated for use on clinical studies in the drug development process. There is not one single guidance to cover all types of biomarker assays and their intended uses. Therefore, it is up to the scientist to piece together a validation strategy based on published papers and other sources. Shown
Aim: To develop a simple and robust LC–MS/MS method to quantify concentrations of micafungin in human plasma for pharmacokinetic studies and therapeutic drug monitoring. Methods: Sample preparation involved protein precipitation with acetonitrile:methanol (83:17% v/v) and [13C6]-micafungin as internal standard. A rapid and selective method for micafungin was validated across a range of 0.200–10.0 mg/l. Results:
Aim: Compared with small molecules, LC–MS quantitation of larger biotherapeutic proteins such as antibodies and antibody–drug conjugates at the intact level presents many challenges in both LC and MS due to their higher molecular weight, bigger size, structural complexity and heterogeneity. Results & conclusion: In this study, quantitation of an intact lysine-linked antibody–drug conjugate, trastuzumab
Aim: High drug concentrations in ocular fluids after intravitreal administration preclude the use of drug-sensitive immunoassays. A drug-tolerant immunoassay is therefore desirable for immunogenicity testing in ophthalmology. Experimental: Immune complex (IC) antidrug antibody (ADA) assays were established for two species. The assays were compared with the bridging assay in ocular and plasma samples from two
Aim: To establish and validate an ultra-high-performance liquid chromatography-tandem mass spectrometry method for the rapid and simultaneous determination of famitinib and its metabolites in human plasma. Results: All analytes demonstrated good correlation coefficients (R2 > 0.99), and the LLOQ was 0.05 ng/ml. The inter- and intraday accuracy and precision, as well as the stability of
Aim: Electromembrane extraction (EME) of weakly basic benzodiazepines was investigated (-1.47 < pKa < 5.01). Materials & Methods: 96-well EME was performed with strongly acidic conditions in the acceptor solution using 250-mM trifluoroacetic acid to maximize ionization. Results & Conclusion: Recoveries more than 80% were obtained for analytes with pKa > 2, whereas EME was
Aim: Estimation of specific IgE is essential for the prevention of allergy progression. Quantitative immuno-PCR (qiPCR) can increase the sensitivity of IgE detection. We aimed to develop qiPCR and compare it to the conventional ELISA in identification of IgE to Alt a 1 and Fel d 1 allergens. Results: Single stranded 60-mer DNA conjugated to
Aim: Molybdenum co-factor deficiencies and isolated sulfite oxidase deficiency are rare autosomal recessively inherited diseases characterized by severe psychomotor impairment, intractable seizures, dislocated lens and dysmorphic facial features. The biochemical diagnosis of these diseases requires the determination of urine sulfocysteine. Materials & methods: Urine sulfocysteine was quantified by an ultra-high performance liquid chromatography–MS/MS assay. The
Aim: This paper describes the salient points in establishing robustness of the cell-based potency assay, with reference to phase-specific qualification. Materials & methods: The methodology was qualified in a thaw for use format utilizing standard parameters. At a later stage, the assay was further developed, and concomitant with requalification the robustness was assessed by fractional