Bioanalysis最新文献

Validation of biomarker assays is crucial for effective drug development and clinical applications. Interlaboratory reproducibility is vital for reliable comparison and combination of data from different centers. This review summarizes interlaboratory studies of quantitative LC-MS-based biomarker assays using reference standards for calibration curves. The following points are discussed: trends in reports, reference and internal standards, evaluation of analytical validation parameters, study sample analysis and normalization of biomarker assay data. Full evaluation of these parameters in interlaboratory studies is limited, necessitating further research. Some reports suggest methods to address variations in biomarker assay data among laboratories, facilitating organized studies and data combination. Method validation across laboratories is crucial for reducing interlaboratory differences and reflecting target biomarker responses.

Monitoring serotype-specific IgG levels against pneumococci is crucial for assessing immunity, vaccine efficacy, and evaluating vaccination programs. The WHO ELISA for pneumococci is a standardized assay ensuring consistency in testing and comparability of results across laboratories. It involves a rigorous testing process to confirm accurate, precise and reliable detection of antibodies. We validated the protocol for 13 pneumococcal serotypes by assessing its specificity, reproducibility (coefficient of variation ≤15%), repeatability (coefficient of variation ≤20%), accuracy, lower limit of quantification, stability, and robustness. We found these parameters were within acceptable ranges and showed excellent performance. Our findings imply that the method employed is appropriate for evaluating 13 valent pneumococcal conjugate vaccine which is introduced in the national immunization program by comparing pre-and post-vaccination IgG response.

Aims: To develop and validate a UHPLC-MS/MS method for lamotrigine (LTG) analysis in human plasma and evaluate its agreement with a homogenous enzyme immunoassay (HEIA). Materials & methods: The UHPLC-MS/MS method was developed and validated according to the USFDA/EMA guidelines. A Bland-Altman plot was used to evaluate the agreement between UHPLC-MS/MS and HEIA. Results: Samples were pretreated with one-step protein precipitation and separated in 2.6 min. The intra- and inter-day bias and imprecisions were -15.8 to 15.0% and less than 11.17%, respectively. The recovery and matrix factor were 98.30 to 111.97%. The mean overestimation of UHPLC-MS/MS compared with HEIA was 21.57%. Conclusion: A rapid, sensitive and robust UHPLC-MS/MS method for plasma LTG analysis was developed and validated and was a 21.57% overestimation compared with HEIA.

Background: The Bicycle^® toxin conjugate BT5528 is a novel peptide therapeutic conjugated to the cytotoxic agent monomethyl auristatin E (MMAE). A bioanalytical assay was developed to quantify BT5528 and unconjugated MMAE in human plasma. Methodology: BT5528 quantitation used a protein precipitation procedure followed by LC-MS/MS detection. Quantitation of MMAE required a selective offline and online solid-phase extraction with detection via LC-MS/MS. Results: BT5528 was quantified over the assay range of 5-2500 ng/ml and free MMAE was quantified over the assay range of 0.05-50 ng/ml. Conclusion: Bioanalytical methods were used in the bioanalysis of intact BT5528 and released MMAE, in a phase I/IIa clinical trial; to date, over 2000 human patient samples have been analyzed.

Aim: A newer LC-MS/MS method was developed and validated for the simultaneous quantification of raloxifene (RL) and cladrin (CL). Methodology: Both drugs were resolved in RP-18 (4.6 × 50 mm, 5 μ) Xbridge Shield column using acetonitrile and 0.1% aqueous solution of formic acid (FA) (70:30% v/v) as mobile phase by using biological matrices in female Sprague-Dawley rats using-MS/MS. Results: The developed method was found to be linear over the concentration ranges of 1-600 ng/ml, and lower limit of quantification was 1 ng/ml for RL and CL, respectively. Pharmacokinetic results of RL+CL showed C_max = 4.23 ± 0.61, 26.97 ± 1.14 ng/ml, at T_max(h) 5.5 ± 1.00 and 3.5 ± 1.00, respectively. Conclusion: Pharmacokinetic study results will be useful in the future for the combined delivery of RL and CL for osteoporosis treatment.

Endogenous therapeutic analytes include hormones, neurotransmitters, vitamins, fatty acids and inorganic elements that are naturally present in the body because either the body produces them or they are present in the normal diet. The accurate measurement of endogenous therapeutic analytes poses a challenge when the administered exogenous therapeutic analyte and its endogenous counterpart cannot be distinguished. In this article, real case examples with endogenous therapeutic analyte bioanalysis during drug development in support of regulatory submissions are collected and presented. The article highlights common challenges encountered and lessons learned related to bioanalysis of endogenous therapeutic analytes and provides practical tips and strategies to consider from a regulatory perspective.

Background: Clinical dosage of toxic and essential elements in blood is well established and the collection method is still by venipuncture. This method has drawbacks and is not suited for everyone. Volumetric absorptive microsampling (VAMS) has been shown to have advantages over venipuncture. Materials & methods: Using inductively coupled plasma tandem mass spectrometry, a method for quantifying elements in whole blood sampled on VAMS was developed/validated. Method's performance was assessed by comparison with whole blood results. Results: Validation and performance assessment tests tend to show that most of the targeted elements provides accurate and reproducible results comparing to a method of reference. Conclusion: Overall, VAMS presents good preliminary results to eventually become an alternative to venipuncture for blood sampling for some trace elements analysis purposes.

Aim: This study aimed to develop a colorimetric approach for quantifying ethanol using smartphone image analysis. Method: This research presents a straightforward smartphone-based colorimetric sensor that efficiently measures ethanol levels in exhaled breath condensate (EBC) samples. The process involved changing the acidic dichromate color in an ethanolic solution, followed by image analysis. Results: The results showed that this method was able to estimate ethanol concentrations in the range of 300-1500 and 1600-8000 μg ml^-1 in EBC. Conclusion: This study was a follow-up study on the previous work published for the determination of ethanol in EBC samples and highlights the potential benefits of using digital images and smartphone applications for ethanol determination in biological samples.

Antibody therapeutic levels in neurodegenerative diseases are often measured in both serum and cerebrospinal fluid (CSF). Due to 0.1% drug partition from serum to CSF and the higher sensitivity needs, usually two different assays are required. The different Gyrolab Bioaffy compact discs can extend the dynamic range of assays. Here, an assay was developed and adapted on two different Gyrolab Bioaffy compact discs (200 and 4000 nl) to achieve the required sensitivity and assay dynamic range needed for the measurement of drug in both serum and CSF. This was accomplished by using the same critical reagents with minimal assay development to transition from a serum to a CSF assay.