The EPRS-ATF4-COLI pathway axis is a potential target for anaplastic thyroid carcinoma therapy.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is recognized as the most aggressive and malignant form of thyroid cancer, underscoring the critical need for effective therapeutic strategies to curb its progression and improve patient prognosis. Halofuginone (HF), a derivative of febrifugine, has displayed antitumor properties across various cancer types. However, there is a paucity of published research focused on the potential of HF to enhance the clinical efficacy of treating ATC. OBJECTIVE: In this study, we thoroughly investigated the antitumor effects and mechanisms of HF in ATC, aiming to discover lead compounds for treating ATC and reveal novel therapeutic targets for ATC tumors. METHODS: A series of assays, including CCK8, colony formation, tumor xenograft models, and ATC tumor organoid experiments, were conducted to evaluate the anticancer properties of HF both in vitro and in vivo. Techniques such as drug affinity responsive target stability (DARTS), western blot, immunofluorescence, and immunohistochemistry were employed to pinpoint HF target proteins within ATC. Furthermore, we harnessed the GEPIA and GEO databases and performed immunohistochemistry to validate the therapeutic potential of the glutamyl-prolyl-tRNA-synthetase (EPRS)- activating transcription factor 4 (ATF4)- type I collagen (COLI) pathway axis in the context of ATC. The study also incorporated RNA sequencing analysis, confocal imaging, and flow cytometry to delve into the molecular mechanisms of HF in ATC. RESULTS: HF exhibited a substantial inhibitory impact on cell proliferation in vitro and on tumor growth in vivo. The DARTS results highlighted HF's influence on EPRS within ATC cells, triggering an amino acid starvation response (AASR) by suppressing EPRS expression, consequently leading to a reduction in COLI expression in ATC cells. The introduction of proline mitigated the effect of HF on ATF4 and COLI expression, indicating that the EPRS-ATF4-COLI pathway axis was a focal target of HF in ATC. Analysis of the expression levels of the EPRS, ATF4, and COLI proteins in thyroid tumors, along with an examination of the relationship between COLI expression and thyroid tumor stage, revealed that HF significantly inhibited the growth of ATC tumor organoids, demonstrating the therapeutic potential of targeting the EPRS-ATF4-COLI pathway axis in ATC. RNA sequencing analysis revealed significant differences in the pathways associated with metastasis and apoptosis between control and HF-treated cells. Transwell assays and flow cytometry experiments provided evidence of the capacity of HF to impede cell migration and induce apoptosis in ATC cells. Furthermore, HF hindered cell metastasis by suppressing the epithelial-mesenchymal transition (EMT) pathway, acting through the inhibition of FAK-AKT-NF-κB/Wnt-ß-catenin signaling and restraining angiogenesis via the VEGF pathway. HF also promoted apoptosis through the mitochondrial apoptotic pathway. CONCLUSION: This study provided inaugural evidence suggesting that HF could emerge as a promising therapeutic agent for the treatment of ATC. The EPRS-ATF4-COLI pathway axis stood out as a prospective biomarker and therapeutic target for ATC.

Novel Isoalantolactone-Based Derivatives as Potent NLRP3 Inflammasome Inhibitors: Design, Synthesis, and Biological Characterization.

The NLRP3 inflammasome has been recognized as a promising therapeutic target in drug discovery for inflammatory diseases. Our initial research identified a natural sesquiterpene isoalantolactone (IAL) as the active scaffold targeting NLRP3 inflammasome. To improve its activity and metabolic stability, a total of 64 IAL derivatives were designed and synthesized. Among them, compound 49 emerged as the optimal lead, displaying the most potent inhibitory efficacy on nigericin-induced IL-1ß release in THP-1 cells, with an IC50 value of 0.29 µM, approximately 27-fold more potent than that of IAL (IC50: 7.86 µM), and exhibiting higher metabolic stability. Importantly, 49 remarkably improved DSS-induced ulcerative colitis in vivo. Mechanistically, we demonstrated that 49 covalently bound to cysteine 279 in the NACHT domain of NLRP3, thereby inhibiting the assembly and activation of NLRP3 inflammasome. These results provided compelling evidence to further advance the development of more potent NLRP3 inhibitors based on this scaffold.

Structure-based design and synthesis of BML284 derivatives: A novel class of colchicine-site noncovalent tubulin degradation agents.

Our previous studies have demonstrated that BML284 is a colchicine-site tubulin degradation agent. To improve its antiproliferative properties, 45 derivatives or analogs of BML284 were designed and synthesized based on the cocrystal structure of BML284 and tubulin. Among them, 5i was the most potent derivative, with IC50 values ranging from 0.02 to 0.05 µM against the five tested tumor cell lines. Structure-activity relationship studies verified that the N1 atom of the pyrimidine ring was the key functional group for its tubulin degradation ability. The 5i-tubulin cocrystal complex revealed that the binding pattern of 5i to tubulin is similar to that of BML284. However, replacing the benzodioxole ring with an indole ring strengthened the hydrogen bond formed by the 2-amino group with E198, which improved the antiproliferative activity of 5i. Compound 5i effectively suppressed tumor growth at an intravenous dose of 40 mg/kg (every 2 days) in paclitaxel sensitive A2780S and paclitaxel resistant A2780T ovarian xenograft models, with tumor growth inhibition values of 79.4% and 82.0%, respectively, without apparent side effects, showing its potential to overcome multidrug resistance. This study provided a successful example of crystal structure-guided discovery of 5i as a colchicine-targeted tubulin degradation agent, expanding the scope of targeted protein degradation.

Design and synthesis of highly selective Janus kinase 3 covalent inhibitors for the treatment of rheumatoid arthritis.

Selective inhibition of Janus kinase 3 (JAK3) is a promising strategy for the treatment of autoimmune diseases. Based on the discovery of a hydrophobic pocket unutilized between the lead compound RB1 and the JAK3 protein, a series of covalent JAK3 inhibitors were prepared by introducing various aromatic fragments to RB1. Among them, J1b (JAK3 IC50 = 7.2 nM, other JAKs IC50 > 1000 nM) stood out because of its low toxicity (MTD > 2 g/kg) and superior anti-inflammatory activity in Institute of Cancer Research mice. Moreover, the acceptable bioavailability (F% = 31.69%) ensured that J1b displayed excellent immune regulation in collagen-induced arthritis mice, whose joints in the high-dose group were almost recovered to a normal state. Given its clear kinase selectivity (Bmx IC50 = 539.9 nM, other Cys909 kinases IC50 > 1000 nM), J1b was nominated as a highly selective JAK3 covalent inhibitor, which could be used to safely treat arthritis and other autoimmune diseases.

Fragment growth-based discovery of novel TNIK inhibitors for the treatment of colorectal cancer.

Traf2-and Nck-interacting protein kinase (TNIK) plays an important role in regulating signal transduction of the Wnt/ß-catenin pathway and is considered an important target for the treatment of colorectal cancer. Inhibiting TNIK has potential to block abnormal Wnt/ß-catenin signal transduction caused by colorectal cancer mutations. We discovered a series of 6-(1-methyl-1H-imidazole-5-yl) quinoline derivatives as TNIK inhibitors through Deep Fragment Growth and virtual screening. Among them, 35b exhibited excellent TNIK kinase and HCT116 cell inhibitory activity with IC50 values of 6 nM and 2.11 µM, respectively. 35b also shown excellent kinase selectivity, PK profiles, and oral bioavailability (84.64%). At a p. o. dosage of 50 mg/kg twice daily 35b suppressed tumor growth on the HCT116 xenograft model. Taken together, 35b is a promising lead compound of TNIK inhibitors, which merits further investigation.

NU6300 covalently reacts with cysteine-191 of gasdermin D to block its cleavage and palmitoylation.

Gasdermin D (GSDMD) serves as a vital mediator of inflammasome-driven pyroptosis. In our study, we have identified NU6300 as a specific GSDMD inhibitor that covalently interacts with cysteine-191 of GSDMD, effectively blocking its cleavage while not affecting earlier steps such as ASC oligomerization and caspase-1 processing in AIM2- and NLRC4-mediated inflammation. On the contrary, NU6300 robustly inhibits these earlier steps in NLRP3 inflammasome, confirming a unique feedback inhibition effect in the NLRP3-GSDMD pathway upon GSDMD targeting. Our study reveals a previously undefined mechanism of GSDMD inhibitors: NU6300 impairs the palmitoylation of both full-length and N-terminal GSDMD, impeding the membrane localization and oligomerization of N-terminal GSDMD. In vivo studies further demonstrate the efficacy of NU6300 in ameliorating dextran sodium sulfate-induced colitis and improving survival in lipopolysaccharide-induced sepsis. Overall, these findings highlight the potential of NU6300 as a promising lead compound for the treatment of inflammatory diseases.

Study on tissue distribution, metabolite profiling, and excretion of [14C]-labeled flonoltinib maleate in rats.

Flonoltinib Maleate (FM) is a dual-target inhibitor that selectively suppresses Janus kinase 2/FMS-like tyrosine kinase 3 (JAK2/FLT3), which is currently in phase I/IIa clinical trial in China for the treatment of myeloproliferative neoplasms (MPNs). In this research, we used [14C]-labeled FM (14C-FM) to investigate the distribution, metabolism, and excretion of FM in rats using High-Performance Liquid Chromatography coupled with High-Resolution Mass Spectrometry/Radioactivity Monitoring (HPLC-HRMS/RAM) and liquid scintillation counter. The results revealed that FM displayed widespread distribution in rats. Furthermore, FM demonstrated rapid clearance without any observed risk of organ toxicity attributed to accumulation. Profiling of FM metabolites in rat plasma, feces, urine, and bile identified a total of 17 distinct metabolites, comprising 7 phase I metabolites and 10 phase II metabolites. The major metabolic reactions involved oxygenation, dealkylation, methylation, sulfation, glucuronidation and glutathione conjugation. Based on these findings, a putative metabolic pathway of FM in rats was proposed. The overall recovery rate in the excretion experiment ranged from 93.04 % to 94.74 %. The results indicated that FM undergoes extensive hepatic metabolism in SD rats, with the majority being excreted through bile as metabolites and ultimately eliminated via feces. A minor fraction of FM (<10 %) was excreted through renal excretion in the form of urine. Integration of the current results with previous pharmacokinetic investigations of FM in rats and dogs enables a comprehensive elucidation of the in vivo ADME processes and characteristics of FM, thereby establishing a solid foundation for subsequent clinical investigations of FM.

Discovery of 4-amino-1,6-dihydro-7H-pyrrolo[2,3-d]pyridazin-7-one derivatives as potential receptor-interacting serine/threonine-protein kinase 1 (RIPK1) inhibitors.

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is an important regulatory factor in the necroptosis signaling pathway, and is considered an attractive therapeutic target for treating multiple inflammatory diseases. Herein, we describe the design, synthesis, and structure-activity relationships of 4-amino-1,6-dihydro-7H-pyrrolo [2,3-d]pyridazin-7-one derivatives as RIPK1 inhibitors. Among them, 13c showed favorable RIPK1 kinase inhibition activity with an IC50 value of 59.8 nM, and high RIPK1 binding affinity compared with other regulatory kinases of necroptosis (RIPK1 Kd = 3.5 nM, RIPK3 Kd = 1700 nM, and MLKL Kd > 30,000 nM). 13c efficiently blocked TNFα-induced necroptosis in both human and murine cells (EC50 = 1.06-4.58 nM), and inhibited TSZ-induced phosphorylation of the RIPK1/RIPK3/MLKL pathway. In liver microsomal assay studies, the clearance rate and half-life of 13c were 18.40 mL/min/g and 75.33 min, respectively. 13c displayed acceptable pharmacokinetic characteristics, with oral bioavailability of 59.55%. In TNFα-induced systemic inflammatory response syndrome, pretreatment with 13c could effectively protect mice from loss of body temperature and death. Overall, these compounds are promising candidates for future optimization studies.

Pomegranate juice-containing serum inhibits migration of hepatocellular carcinoma cells and promotes apoptosis by induction of mitochondrial dysfunction.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide, with an insidious onset and poor prognosis. Pomegranate is a fruit rich in many natural products with anti-cancer potential; however, its direct biological effects are difficult to evaluate in vitro because of changes in its active components after absorption and metabolism. This study was conducted to prepare pomegranate juice-containing serum (PJ serum) by gavage of pomegranate juice (PJ) in rats and to collect serum. The aim was to investigate the components and the effects of PJ serum on HCC cells by serum pharmacology. 56 compounds were identified in the PJ serum, including 6 prototype components. PJ serum selectively inhibited HCC cells proliferation and migration, and it promoted apoptosis of HCC cells without affecting LO2 cells activity. Furthermore, PJ serum reduced the mitochondrial membrane potential and increased the calcium ion concentration in HCC cells. Mechanistically, PJ serum up-regulated the expression of the Bax family, Caspases and TIMP2/MMP2, and down-regulated the expression of MMP9. This study revealed that PJ serum inhibited HCC cell migration by regulating the TIMP2/MMP2 balance and MMP9 expression and promoted HCC cell apoptosis by inducing mitochondrial dysfunction and causing a Caspase cascade. The polyphenols and flavonoids in PJ may be important components responsible for its anti-HCC activity after metabolism.

Discovery of Potent and Selective Phosphatidylinositol 3-Phosphate 5-Kinase (PIKfyve) Inhibitors as Methuosis Inducers.

Cytoplasmic vacuolation-associated cell death, known as methuosis, offers a promising nonapoptotic approach for cancer treatment. In this study, we outline the synthesis and evaluation of potent methuosis-inducing compounds. These compounds selectively induce cell death, characterized by extensive cytoplasmic vacuolation in HeLa and MDA-MB-231 cells. Notably, compound L22 exhibited a remarkable interaction with PIKfyve kinase, boasting a Kd value of 0.47 nM, surpassing the positive controls D-13 and MOMIPP in potency. Furthermore, it is important to highlight that cell death induced by compound L22 is unequivocally attributed to methuosis as it differs from apoptosis, necrosis, or autophagy. Importantly, when administered orally, L22 effectively inhibited tumor growth in a HeLa xenograft model without any apparent signs of toxicity. These results underscore the potential of L22 as a valuable tool for in-depth investigations into the mechanisms of methuosis and as a promising lead compound to guide structural optimization.

Discovery, Optimization, and Evaluation of Potent and Selective DNA-PK Inhibitors in Combination with Chemotherapy or Radiotherapy for the Treatment of Malignancies.

Given the multifaceted biological functions of DNA-PK encompassing DNA repair pathways and beyond, coupled with the susceptibility of DNA-PK-deficient cells to DNA-damaging agents, significant strides have been made in the pursuit of clinical potential for DNA-PK inhibitors as synergistic adjuncts to chemo- or radiotherapy. Nevertheless, although substantial progress has been made with the discovery of potent inhibitors of DNA-PK, the clinical trial landscape requires even more potent and selective molecules. This necessitates further endeavors to expand the repertoire of clinically accessible DNA-PK inhibitors for the ultimate benefit of patients. Described herein are the obstacles that were encountered and the solutions that were found, which eventually led to the identification of compound 31t. This compound exhibited a remarkable combination of robust potency and exceptional selectivity along with favorable in vivo profiles as substantiated by pharmacokinetic studies in rats and pharmacodynamic assessments in H460, BT474, and A549 xenograft models.

Recent Progress and Prospects of Small Molecules for NLRP3 Inflammasome Inhibition.

NLRP3 inflammasome is a multiprotein complex involved in host immune response─which exerts various biological effects by mediating the maturation and secretion of IL-1ß and IL-18─and pyroptosis. However, its aberrant activation could cause amplification of inflammatory effects, thereby triggering a range of ailments, including Alzheimer's disease, Parkinson's disease, rheumatoid arthritis, gout, type 2 diabetes mellitus, and cancer. For the past few years, as an attractive anti-inflammatory target, NLRP3-targeting small-molecule inhibitors have been widely reported by both the academic and the industrial communities. In order to deeply understand the advancement of NLRP3 inflammasome inhibitors, we provide comprehensive insights and commentary on drugs currently under clinical investigation, as well as other NLRP3 inflammasome inhibitors from a chemical structure point of view, with an aim to provide new insights for the further development of clinical drugs for NLRP3 inflammasome-mediated diseases.

Discovery of Triazinone Derivatives as Novel, Specific, and Direct NLRP3 Inflammasome Inhibitors for the Treatment of DSS-Induced Ulcerative Colitis.

NLRP3 is an intracellular sensor protein that causes inflammasome formation and pyroptosis in response to a wide range of stimuli. Aberrant activation of NLRP3 inflammasome has been implicated in various chronic inflammatory diseases, making it a promising target for therapeutic intervention. In this work, a series of novel triazinone inhibitors of NLRP3 inflammasome were designed and synthesized. Compound L38 was identified for its excellent activity and acceptable metabolic stability among 41 compounds. Additionally, mechanism studies indicated that L38 inhibited NLRP3 inflammasome activation and pyroptosis by suppressing gasdermin D cleavage, ASC oligomerization, and NLRP3 inflammasome assembly while leaving mitochondrial ROS production, lysosome damage, and chloride/potassium efflux unaffected. Further investigation revealed that L38 could bind to the NACHT domain to exert inflammatory properties. Importantly, L38 exhibited positive therapeutic effects in DSS-induced ulcerative colitis mouse model. Taken together, this study presents a promising inhibitor of NLRP3 inflammasome deserving further investigation.

Piper nigrum Extract Inhibits the Growth of Human Colorectal Cancer HT-29 Cells by Inducing p53-Mediated Apoptosis.

Colorectal cancer (CRC) is a prevalent malignancy of the digestive tract with the second highest mortality rate globally. Piper nigrum is a widely used traditional medicinal plant, exhibiting antitumor activity against various tumor cells. At present, research on the effect of Piper nigrum on CRC is limited to in vitro cytotoxicity, lacking comprehensive mechanism investigations. This study aimed to explore the inhibitory effect and mechanism of Piper nigrum extract (PNE) on HT-29 cells. Firstly, we identified the chemical components of PNE. Then, MTT assay, colony formation assay, JC-1 staining, and flow cytometry were used to analyze the effect of PNE on HT-29 cells in vitro. A xenograft model, histopathological examination, immunohistochemistry, and western blot were used to evaluate the tumor growth inhibitory activity and mechanism of PNE in vivo. The results indicated that PNE could inhibit cell proliferation and colony formation, reduce mitochondrial membrane potential, induce cell apoptosis in vitro, and inhibit tumor growth in vivo. Furthermore, PNE could regulate p53 and its downstream proteins, and subsequently activate the caspase-3 pathway. In summary, PNE probably induced apoptosis of HT-29 cells through the mitochondrial pathway mediated by p53. All these results suggested that PNE might be a potential natural-origin anti-CRC drug candidate.

Design, Synthesis, and Biological Evaluation of Novel P2X7 Receptor Antagonists for the Treatment of Septic Acute Kidney Injury.

Sepsis-associated acute kidney injury (AKI) is a serious clinical problem, without effective drugs. Abnormal activation of the purinergic P2X7 receptor (P2X7R) in septic kidneys makes its antagonist a promising therapeutic approach. Herein, a series of novel P2X7R antagonists were designed, synthesized, and structurally optimized. Based on in vitro potency in human/mouse P2X7R using HEK293 cells, hepatic microsomal stability, and pharmacokinetic and preliminary in vivo assessments, compound 14a was identified by respective human and mouse P2X7R IC50 values of 64.7 and 10.1 nM, together with favorable pharmacokinetic properties. Importantly, 14a dose-dependently alleviated kidney dysfunction and pathological injury in both lipopolysaccharide (LPS)- and cecal ligation/perforation (CLP)-induced septic AKI mice with a good safety profile. Mechanistically, 14a could suppress NLRP3 inflammasome activation to inhibit the expression of cleaved caspase-1, gasdermin D, IL-1ß, and IL-18 in the injured kidneys of septic mice. Collectively, these results highlighted that P2X7R antagonist 14a exerted a therapeutic potential against septic AKI.

Discovery and Evaluation of 3-Quinoxalin Urea Derivatives as Potent, Selective, and Orally Available ATM Inhibitors Combined with Chemotherapy for the Treatment of Cancer via Goal-Oriented Molecule Generation and Virtual Screening.

ATM plays an important role in DNA damage response and is considered a potential target in cancer therapies. In this study, a goal-directed molecular generation approach based on ligand similarity and target specificity was applied to sample active molecules, and they were screened virtually to identify the theoretical lead compound 7a, which was later shown to inhibit ATM adequately. However, there is a main concern about its poor metabolic stability in vitro. Subsequent optimization was performed to improve the potency and selectivity toward ATM and attenuate the hepatic clearance in vitro, culminating in the identification of 10r with nanomolar ATM inhibition, excellent cellular sensitivity to radiation and chemotherapy drugs, and impressive pharmacokinetic profiles. Furthermore, 10r combined with irinotecan demonstrated a synergistic antitumor efficacy in SW620 xenograft models, suggesting that it could be a promising candidate drug combined with chemotherapy for the treatment of cancer.

Discovery of indoline-based derivatives as effective ROCK2 inhibitors for the potential new treatment of idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and devastating lung disease with a median survival of only 3-5 years. Due to the lack of effective therapy, IPF threatens human health. Recently, increasing reports have indicated that Rho-associated coiled-coil protein kinases (ROCKs) play important roles in the development of IPF and might represent a novel target for the treatment of IPF. Herein, a new series of selective ROCK2 inhibitors based on indoline were designed and synthesized. Structural modification resulted in optimized compound 9b with an IC50 value of 6 nM against ROCK2 and the inhibition of collagen gel contraction. Cellular assays demonstrated that 9b could significantly suppress the expression of collagen I and α-SMA, and inhibited ROCK signaling pathway. Oral administration of compound 9b (10 mg/kg) exerted more significant anti-pulmonary fibrosis effects than nintedanib (100 mg/kg) and KD025 (100 mg/kg) in a bleomycin-induced IPF rat model, suggesting that 9b could serve as a potential lead compound for the treatment of IPF.

Discovery of pyrimidine-5-carboxamide derivatives as novel salt-inducible kinases (SIKs) inhibitors for inflammatory bowel disease (IBD) treatment.

Salt-inducible kinases (SIKs) play a crucial role in inflammation process, acting as molecular switches that regulate the transformation of M1/M2 macrophages. HG-9-91-01 is a SIKs inhibitor with potent inhibitory activity against SIKs in the nanomolar range. However, its poor drug-like properties, including a rapid elimination rate, low in vivo exposure and high plasma protein binding rate, have hindered further research and clinical application. To improve the drug-like properties of HG-9-91-01, a series of pyrimidine-5-carboxamide derivatives were designed and synthesized through a molecular hybridization strategy. The most promising compound 8h was obtained with favorable activity and selectivity on SIK1/2, excellent metabolic stability in human liver microsome, enhanced in vivo exposure and suitable plasma protein binding rate. Mechanism research showed that compound 8h significantly up-regulated the expression of anti-inflammatory cytokine IL-10 and reduced the expression of pro-inflammatory cytokine IL-12 in bone marrow-derived macrophages. Furthermore, it significantly elevated expression of cAMP response element-binding protein (CREB) target genes IL-10, c-FOS and Nurr77. Compound 8h also induced the translocation of CREB-regulated transcriptional coactivator 3 (CRTC3) and elevated the expression of LIGHT, SPHK1 and Arginase 1. Additionally, compound 8h demonstrated excellent anti-inflammatory effects in a DSS-induced colitis model. Generally, this research indicated that compound 8h has the potential to be developed as an anti-inflammatory drug candidate.

UPLC-MS/MS method development and application to pharmacokinetic study in rats and dogs of Flonoltinib Maleat.

Flonoltinib Maleate (FM) is a novel selective inhibitor of Janus kinase 2/FMS-like tyrosine kinase 3 (JAK2/FLT3). In this study, we developed an ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method to measure the plasma concentrations of FM in rats and dogs for pharmacokinetic studies. For chromatographic separation, we used a BEH C18 column (2.1 × 50 mm, 1.7 µm particle size) in HPLC. The mobile phase A consisted of a water solution containing 0.1% formic acid (FA) and 2 mM NH4OAc, mixed with acetonitrile (ACN) (V:V = 95:5). The mobile phase B was a water solution containing 0.1% FA and 2 mM NH4OAc, mixed with ACN (V:V = 5:95), which was used for gradient elution. We used multiple reactive ion detection (MRM) mode and electrospray ionization positive (ESI+) mode for quantitative analysis. The standard curve was linear in the concentration range of 0.5 to 500 ng/ml in rat and dog plasma. The intra-batch and inter-batch precision (RSD%) of FM in rat and dog plasma was less than 15%. The intra-batch and inter-batch accuracy was 88.3-106.5% and 92.0-100.6% in rats, and 94.7-106.6% and 95.3-103.8% in dogs, respectively. The RSD (%) of matrix factors (MF) normalized to the internal standard (IS) of FM in rat and dog plasma was ≤5.6% and ≤3.0%, respectively. The extraction recovery and carryover were considered acceptable. When the sample concentration was higher than the upper limit of quantitation (ULOQ), the 10-fold dilution was reliable within the limits of acceptability. The UPLC-MS/MS method developed in this study was successfully applied in measuring the pharmacokinetic parameters of FM in rats and dogs after intravenous and oral administration, laying a foundation for the preclinical pharmacokinetic study of FM and providing a reference for clinical pharmacokinetic studies.

In vitro and in vivo metabolic profiling of PD105, a PI3Kδ inhibitor, using UHPLC-Q-Exactive plus-MS.

PD105, a PI3Kδ inhibitor, is a candidate for the treatment of rheumatoid arthritis. This study aims to identify the metabolic profiling in vitro and in vivo by UHPLC-Q-Exactive Plus-MS.The in vitro metabolism of PD105 was studied by mouse liver microsomes and hepatocytes, while the in vivo metabolic profiling was obtained from mouse plasma, urine, and faeces. A total of 20 metabolites were tentatively identified based on accurate mass, fragment pathways, and characteristic fragment ions, including 4 in vitro and 20 in vivo.The proposed metabolic pathways of PD105 showed that there were 18 phase I metabolites and 2 phase II metabolites. The phase I metabolic pathways included oxidation, hydration, desaturation and oxidative dechlorination, while the phase II metabolic reactions were mainly methylation and arginine conjugation. Among them, oxidation was the main metabolic pathway of PD105.The comprehensive metabolic profiling contributed to further elucidation of pharmacological action and mechanism of PD105.