Bioanalysis最新文献

Formalin-fixed paraffin-embedded (FFPE) is a form of preservation and preparation for biopsy specimens. FFPE tissue specimens are readily available as part of oncology studies because they are often collected for disease diagnosis or confirmation. FFPE tissue specimens could be extremely useful for retrospective studies on protein biomarkers because the samples preserved in FFPE blocks could be stable for decades. However, LC-MS bioanalysis of FFPE tissues poses significant challenges. In this Perspective, we review the benefits and recent developments in LC-MS approach for targeted protein biomarker and protein therapeutic analysis using FFPE tissues and their clinical and translational applications. We believe that LC-MS bioanalysis of protein biomarkers in FFPE tissue specimens represents a great potential for its clinical applications.

Aim: The fixed-dose combination of moxifloxacin (MOXI) and ketorolac tromethamine (KTR) is widely used for the treatment of bacterial keratitis. Thus, a new LC-MS/MS method was developed to determine MOXI and KTR in lacrimal fluid. Methods: Bioanalysis was performed using a Shimadzu 8050 LC-MS/MS in electrospray ionization-positive mode and the method was validated per US FDA guidelines. Isocratic separation was performed with a Waters Symmetry C₁₈ column using methanol and 0.1% formic acid containing deionized water (85:15, v/v). Results & conclusion: An easy, quick and selective method was established and applied to assess the ocular pharmacokinetic profile of a commercially available formulation containing MOXI and KTR. Based on the pharmacokinetic data, this work describes pharmacokinetics-based dosage regimen calculations and their clinical significance.

Background: The authors report the relevance of using a point of care test (Helge^®) for free hemoglobin determination and concordance of the values the with Cobas^® 8000 and spectrophotometer methods. Results: The within-run of the point of care test was <3%. Good correlations among the three methods were observed and an acceptable concordance for hemolysis index values from 50 mg/dl. An excellent agreement between the Cobas 8000 and the spectrophotometer was found. Conclusion: Automated methods represent methods of choice for free hemoglobin determination. An advantage of the Helge system is that it can be applied to samples experiencing a delay in evaluation due to the long distance between the collection site and the central laboratory. Another advantage is its use at the bedside, in the monitoring of extracorporeal membrane oxygenation patients.

Thyroglobulin (Tg) is a large protein secreted exclusively by the thyroid gland. In a clinical setting, it is measured for the purpose of follow-up of thyroidectomy patients. However, Tg measurements are often impeded by the presence of Tg autoantibodies and/or heterophylic antibodies that interfere with most measuring platforms. This presents a global problem in thyroid cancer patients who need to be postoperatively monitored for recurrent or residual disease. Therefore, in this paper we offer an overview of the existing methodologies and alternative approaches for Tg measurements that are a focus of research worldwide. These include Tg mRNA measurements, exosomal Tg detection, the use of alternative analytes (liquid biopsies) and the development of new approaches for preanalytical sample treatment.

Messenger RNA (mRNA)-based therapeutics have emerged as a promising modality for various clinical applications, necessitating robust methods for mRNA quantification. This biodistribution study compares the performance of branched DNA and reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) assays for measuring lipid nanoparticle-encapsulated mRNA. Following intravenous administration of nascent peptide imaging luciferase mRNA (1 mg/kg) to rats, mRNA levels in various tissues and serum were quantified using both assays. Statistical analyses, including Bland-Altman, Deming regression and Passing-Bablok regression, were employed to assess method comparability and reproducibility. The results indicated that mRNA pharmacokinetics measured by branched DNA and RT-qPCR were largely consistent across tissues, with RT-qPCR showing greater reproducibility across multiple laboratories. RT-qPCR also demonstrated a wider dynamic range and higher sensitivity, making it a more versatile option for large-scale studies. Despite some differences in data due to tissue types and timepoints, both methods provided comparable pharmacokinetic profiles for mRNA quantification. This study underscores the importance of selecting an appropriate quantification method based on study requirements and highlights RT-qPCR's adaptability for multisite research, especially for the clinical development of mRNA-based therapeutics.

Aim: Identifying drugs of abuse and their metabolites in plasma is vital in both forensic and clinical toxicology. While the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method offers an efficient approach to sample preparation, its application is complex due to the wide-ranging properties of target analytes and the challenges posed by biological matrix interferences. This study aims to develop a microQuEChERS approach for the quantification of 14 drugs of abuse and metabolites utilizing minimal sample and solvent volumes.Methods: The microQuEChERS method involved using 10 μl plasma samples, 25 mg of a salt mixture and 150 μl of acetonitrile. Extracts were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), with a 7.5 min run. The assay was validated according to bioanalytical guidelines.Results: The accuracy was 96.8-112.4%. The within-assay precision was within 2.0-8.9% and the between-assay precision was within 3.2-8.2%. Matrix effects were found to range from -5.7 to 13.5%. The extraction yield was higher than 74.7%.Conclusion: This study described a microQuEChERS sample preparation approach for determining drugs of abuse and metabolites using plasma microsamples and LC-MS/MS. The approach is efficient, environmentally friendly and suitable for scenarios with limited amounts of biological samples.

Aim: Brincidofovir has been approved by the US FDA for the treatment of smallpox via the "Animal Rule". The active moiety, cidofovir diphosphate (CDV-PP), was measurable in human peripheral blood mononuclear cells (PBMCs), but quantitation in animals was challenging given their limited blood volume. The aim of this study was to optimize PBMC isolation from rabbit and mouse blood to allow quantitation of CDV-PP.Materials & methods: PBMC isolation methods using various separation media were evaluated using blood from naive and brincidofovir-dosed animals. CDV-PP was quantified using liquid chromatography tandem mass spectrometry.Results & conclusion: PBMC isolation yields were increased by >fourfold compared with yields obtained using human methods, allowing cross-species exposure comparisons.

Background: Volumetric absorptive microsamples (VAMS) can support pharmacokinetic / pharmacodynamic studies. We present the bioanalytical method development for the simultaneous quantification of ampicillin, cefepime, ceftriaxone, meropenem, piperacillin, tazobactam, and vancomycin from VAMS. Methods & results: Optimal extraction, chromatographic, and mass spectrometry conditions were identified. Maximum extraction recoveries included 100 μl of water for rehydration and methanol for protein precipitation. Chromatographic separation used Phenomenex Kinetex^™ Polar C18 column with a mobile phase comprising water/acetonitrile with formic acid and was fully validated. Hematocrit effects were only observed for vancomycin. Samples were stable for 90 days at -80°C except for meropenem, which was stable for 60 days. Conclusion: Multiple antibiotics can be assayed from a single VAMS sample to facilitate pharmacokinetic/pharmacodynamic studies.

We have developed and validated a novel LC-MS/MS method for the simultaneous quantification of ZEN-3694 and its active metabolite ZEN-3791 in human plasma after protein precipitation. Stable isotope-labeled versions were used as internal standards. Chromatographic separation was achieved on a Kinetex C18 column using 0.1% formic acid in H₂O and 0.1% formic acid in MeOH as mobile phases. Detection was performed via positive electrospray ionization mode with multiple reaction monitoring. The assay exhibited linearity in the concentration range of 5-5000 ng/ml for both analytes. Intra- and inter-assay precision and accuracy were within ±11%. ZEN-3694 and ZEN-3791 recoveries were between 93 and 105%. This LC-MS/MS assay is an essential tool to study ZEN-3694 in an ongoing clinical trial (NCT04840589).