Development and Validation of a LC-MS/MS Method for Quantification of Mobocertinib (TAK-788) in Plasma and its Application to Pharmacokinetic Study in Rats.

AIM AND OBJECTIVE: An analytical method for the determination of mobocertinib, an investigational tyrosine kinase inhibitor, was developed and optimized by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) in rat plasma. MATERIALS AND METHODS: Plasma samples were pretreated by the protein precipitation method with a methanol solution of osimertinib as the internal standard (IS). Chromatographic separation was performed using an Inertsil ODS-3 column (50 mm × 4.6 mm, I.D. 5 µm) with the temperature maintained at 40°C. The mobile phase consisted of water (containing 0.1% formic acid) and methanol in a gradient mode at a flow rate of 0.5 mL/min. Mass spectrometric detection was carried out in the selected reaction monitoring (SRM) mode with positive electrospray ionization, and the mass transitions of mobocertinib and osimertinib were m/z 587.01 → 71.88 and m/z 499.80 → 71.94, respectively. The method was validated in terms of selectivity, linearity, accuracy and precision, extraction recovery and matrix effect, stability and carryover as per the guidelines for bioanalytical method validation (FDA, 2018). The method was applied to the pharmacokinetic study of mobocertinib in rats by oral gavage at the doses of 2, 6, and 18 mg/kg. A total of 216 plasma samples from 18 rats were analyzed. RESULTS: The results showed good linearity over the range of 1-1000 ng/mL (R2 = 0.9957). The intra-batch accuracy was within 94.65-102.59% and the precision was within 5.49-10.46%. The inter-batch accuracy was within 97.08-102.25% with a precision of 7.54-10.13%. The extraction recovery and matrix factor were acceptable for the bioanalysis of mobocertinib. Additionally, mobocertinib was found to be stable under the detected conditions. Mobocertinib showed linear pharmacokinetic characteristics following oral administration to rats at 2.0-18.0 mg/kg. CONCLUSION: The developed and validated method was successfully employed in the pharmacokinetic study in rats following oral administration of mobocertinib at the doses of 2, 6, and 18 mg/kg.

Deep sequencing reveals the skewed B-cell receptor repertoire in plaques and the association between pathogens and atherosclerosis.

The immune/inflammatory responses regulated by B cells are the critical determinants of atherosclerosis. B-cell receptor (BCR) plays pivotal roles in regulating B cell function. However, the composition and molecular characteristics of the BCR repertoire in atherosclerotic patients have not been fully elucidated. Herein we analyzed BCR repertoire in circulation and plaques of atherosclerotic patients by sequencing the BCR heavy chain complement determining region 3 (BCRH CDR3). Our data showed that in plaques, BCR repertoire was dramatically skewed and their combinations and diversity were significantly decreased, while the frequency of public and dominant B-cell clones was markedly increased. Additionally, BCRH CDR3 in plaques had higher positive selection pressure than that in the peripheral blood of normal subjects and atherosclerotic patients. Moreover, the BCRH CDR3 of some B cell clones specifically expanded in plaques were similar to that of antibodies which recognized certain pathogens including Influenza A virus, implying the possibility of the association between pathogens and atherosclerosis. The present study contributed to understand the roles of B cells in atherosclerosis. The design of specific antibodies based on the B cell clones specifically expanded in plaques might yield useful tools to reveal the pathogenesis of atherosclerosis, assess or alleviate the progression of atherosclerosis.