Identification and characterization of in silico, in vivo, in vitro, and reactive metabolites of infigratinib using LC-ITMS: bioactivation pathway elucidation and in silico toxicity studies of its metabolites

Identification of the human Cytochrome P450 enzymes (P450s) responsible for metabolizing infigratinib to its pharmacologically active Metabolites, BHS697, and CQM157, and assessment of their in vitro inhibition of P450s and UDP-glucuronosyltransferases (UGTs)

Infigratinib, an oral FGFR inhibitor for advanced cholangiocarcinoma, yielded two active metabolites, BHS697 and CQM157, with similar receptor affinity. Our study characterized P450s that are responsible for the metabolism of infigratinib to its two major active metabolites, BHS697 and CQM157. In vitro inhibition of P450s and UGTs by infigratinib, BHS697 or CQM157 was further investigated. The unbound apparent Km values for metabolism of infigratinib to BHS697 by HLM, human recombinant CYP2C8, CYP2C19, CYP2D6 and CYP3A4 enzymes are 4.47, 0.65, 2.50, 30.6 and 2.08 μM, while Vmax values are 90.0 pmol/min/mg protein, 0.13, 0.027, 0.81, and 0.56 pmol/min/pmol protein, respectively. The unbound apparent Km value for metabolism of infigratinib to CQM157 by HLM is 0.049 μM, while the Vmax value is 0.32 pmol/min/mg protein respectively. In HLM, infigratinib displayed moderate inhibition of CYP3A4 and CYP2C19 and weak or negligible inhibition of other P450 isoforms. BHS697 exhibited weak inhibition of CYP2B6, CYP2C9, CYP2C19 and CYP3A4, and no inhibition of CYP2C8 and CYP2D6. CQM157 moderately inhibited CYP2C9 and CYP3A4, and weakly or negligibly inhibited other P450 isoforms. Regarding UGTs, infigratinib moderately inhibited UGT1A4 and weakly inhibited UGT1A1, respectively. BHS697 weakly inhibited UGT1A1. In contrast, CQM157 moderately inhibited both UGT1A1 and UGT1A4. Our findings provide novel insights into the metabolism of and potential DDIs implicating infigratinib.

Prediction of cytochrome P450-mediated bioactivation using machine learning models and in vitro validation

Cytochrome P450 (P450)-mediated bioactivation, which can lead to the hepatotoxicity through the formation of reactive metabolites (RMs), has been regarded as the major problem of drug failures. Herein, we purposed to establish machine learning models to predict the bioactivation of P450. On the basis of the literature-derived bioactivation dataset, models for Benzene ring, Nitrogen heterocycle and Sulfur heterocycle were developed with machine learning methods, i.e., Random Forest, Random Subspace, SVM and Naïve Bayes. The models were assessed by metrics like "Precision", "Recall", "F-Measure", "AUC" (Area Under the Curve), etc. Random Forest algorithms illustrated the best predictability, with nice AUC values of 0.949, 0.973 and 0.958 for the test sets of Benzene ring, Nitrogen heterocycle and Sulfur heterocycle models, respectively. 2D descriptors like topological indices, 2D autocorrelations and Burden eigenvalues, etc. contributed most to the models. Furthermore, the models were applied to predict the occurrence of bioactivation of an external verification set. Drugs like selpercatinib, glafenine, encorafenib, etc. were predicted to undergo bioactivation into toxic RMs. In vitro, IC50 shift experiment was performed to assess the potential of bioactivation to validate the prediction. Encorafenib and tirbanibulin were observed of bioactivation potential with shifts of 3-6 folds or so. Overall, this study provided a reliable and robust strategy to predict the P450-mediated bioactivation, which will be helpful to the assessment of adverse drug reactions (ADRs) in clinic and the design of new candidates with lower toxicities.

A comprehensive overview of selective and novel fibroblast growth factor receptor inhibitors as a potential anticancer modality

The arrival of comprehensive genome sequencing has accelerated the understanding of genetically aberrant advanced cancers and target identification for possible cancer treatment. Fibroblast growth factor receptor (FGFR) gene alterations are frequent findings in various rare and advanced cancers refractive to mainstay chemo-therapy or surgical interventions. Several FGFR inhibitors have been developed for addressing these genetically altered FGFR-harboring malignancies, and some have performed well in clinical trials. In contrast, others are still being investigated in different phases of clinical trials. FDA has approved four anticancer agents such as erdafitinib, pemigatinib, infigratinib, and futibatinib, for clinical use in oncogenic FGFR-driven malignancies. These include cholangiocarcinoma, urothelial carcinoma, and myeloid/lymphoid malignancies. Pemigatinib is the only FGFR inhibitor globally approved (USA, EU, and Japan) and available as a targeted therapy for two types of cancer, including FGFR2 fusion or other rearrangements harboring cholangiocarcinoma and relapsed/refractory myeloid/lymphoid neoplasms with FGFR1 rearrangements. Myeloid/lymphoid neoplasm is the latest area of application added to the therapeutic armamentarium of FGFR inhibitors. Furthermore, futibatinib is the first-in-class covalent or irreversible pan-FGFR inhibitor that has received FDA approval for locally advanced or metastatic intrahepatic cholangiocarcinoma harboring FGFR2 gene aberrations. This review highlights the current clinical progress concerning the safety and efficacy of all the approved FGFR-TKIs (tyrosine kinase inhibitors) and their ongoing investigations in clinical trials for other oncogenic FGFR-driven malignancies.

Medicinal chemistry perspectives on the development of piperazine-containing HIV-1 inhibitors

The Human immunodeficiency virus (HIV) is the causative agent of acquired immunodeficiency syndrome (AIDS), one of the most perilous diseases known to humankind. A 2023 estimate put the number of people living with HIV around 40 million worldwide, with the majority benefiting from various antiretroviral therapies. Consequently, the urgent need for the development of effective drugs to combat this virus cannot be overstated. In the realm of medicinal and organic chemistry, the synthesis and identification of novel compounds capable of inhibiting HIV enzymes at different stages of their life cycle are of paramount importance. Notably, the spotlight is on the progress made in enhancing the potency of HIV inhibitors through the use of piperazine-based compounds. Multiple studies have revealed that the incorporation of a piperazine moiety results in a noteworthy enhancement of anti-HIV activity. The piperazine ring assumes a pivotal role in shaping the pharmacophore responsible for inhibiting HIV-1 at critical stage, including attachment, reverse transcription, integration, and protease activity. This review also sheds light on the various opportunities that can be exploited to develop effective antiretroviral targets and eliminate latent HIV reservoirs. The advancement of highly potent analogues in HIV inhibitor research has been greatly facilitated by contemporary medicinal strategies, including molecular/fragment hybridization, structure-based drug design, and bioisosterism. These techniques have opened up new avenues for the development of compounds with enhanced efficacy in combating the virus.

Sustainable chromatographic quantitation of multi-antihypertensive medications: application on diverse combinations containing hydrochlorothiazide along with LC-MS/MS profiling of potential impurities: greenness and whiteness evaluation

Cardiovascular disorders are among the leading causes of death worldwide, especially hypertension, a silent killer syndrome requiring multiple drug therapy for appropriate management. Hydrochlorothiazide is an extensively utilized thiazide diuretic that combines with several antihypertensive drugs for effective treatment of hypertension. In this study, sustainable, innovative and accurate high performance liquid chromatographic methods with diode array and tandem mass detectors (HPLC-DAD and LC-MS/MS) were developed, optimized and validated for the concurrent determination of Hydrochlorothiazide (HCT) along with five antihypertensive drugs, namely; Valsartan (VAL), Amlodipine besylate (AML), Atenolol (ATN), Amiloride hydrochloride (AMI), and Candesartan cilextil (CAN) in their diverse pharmaceutical dosage forms and in the presence of Chlorothiazide (CT) and Salamide (DSA) as HCT officially identified impurities. The HPLC-DAD separation was achieved utilizing Inertsil ODS-3 C18 column (250 × 4.6 mm, 5 μm) attached with photodiode array detection at 225.0 nm. Gradient elution was performed utilizing a mixture of solvent A (20.0 mM potassium dihydrogen phosphate, pH 3.0 ± 0.2, adjusted with phosphoric acid) and solvent B (acetonitrile) at ambient temperature. Linearity ranges were 0.1-100.0 µg/mL for HCT, VAL, AML and CAN, 0.05 -100.0 µg/mL for both ATN and AMI and 0.05-8.0 µg/mL for both CT and DSA. Additionally, this work describes the use of liquid chromatography-electrospray-tandem mass spectrometry for the accurate detection and quantification of the impurities; CT and DSA in the negative mode utilizing triple quadrupole mass spectrometry. The linearity ranges for those impurities were 1.0-200.0 ng/mL and 5.0-200.0 ng/mL for CT and DSA, respectively. Developed methods' validation was achieved in accordance with International Conference on Harmonization (ICH) guidelines. Upon applying liquid chromatographic techniques for the drug analysis, a green and sustainable assessment have to be handled due to the consumption of energy and many solvents. Through the use of the HEXAGON, Analytical Greenness (AGREE) and White Analytical Chemistry (WAC) tools, greenness and sustainability have been statistically assessed. The optimized HPLC-DAD and LC-MS/MS methods were fast, accurate, precise, and sensitive, and consequently could be applied for conventional analysis and quality control of the proposed drugs in their miscellaneous dosage forms for the purpose of reducing laboratory wastes, time of the analysis time, effort, and cost.

Effects of bergapten on the pharmacokinetics of macitentan in rats both in vitro and in vivo

Macitentan was approved by the United States Food and Drug Administration (FDA) in 2013 for the treatment of pulmonary arterial hypertension (PAH). Bergapten is a furanocoumarin that is abundant in Umbelliferae and Rutaceae plants and is widely used in many Chinese medicine prescriptions. Considering the possible combination of these two compounds, this study is aimed to investigate the effects of bergapten on the pharmacokinetics of macitentan both in vitro and in vivo. Rat liver microsomes (RLMs), human liver microsomes (HLMs), and recombinant human CYP3A4 (rCYP3A4) were used to investigate the inhibitory effects and mechanisms of bergapten on macitentan in vitro. In addition, pharmacokinetic parameters were also studied in vivo. Rats were randomly divided into two groups (six rats per group), with or without bergapten (10 mg/kg), and pretreated for 7 days. An oral dose of 20 mg/kg macitentan was administered to each group 30 min after bergapten or 0.5% CMC-Na administration on day 7. Blood was collected from the tail veins, and the plasma concentrations of macitentan and its metabolites were assessed by ultra-performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS). Finally, we analyzed the binding force of the enzyme and two small ligands by in silico molecular docking to verify the inhibitory effects of bergapten on macitentan. The in vitro results revealed that the IC₅₀ values for RLMs, HLMs, and rCYP3A4 were 3.84, 17.82 and 12.81 μM, respectively. In vivo pharmacokinetic experiments showed that the AUC_(0-t), AUC_(0-∞), and C_max of macitentan in the experimental group (20,263.67 μg/L*h, 20,378.31 μg/L*h and 2,999.69 μg/L, respectively) increased significantly compared with the control group (7,873.97 μg/L*h, 7,897.83 μg/L*h and 1,339.44 μg/L, respectively), while the CL_z/F (1.07 L/h/kg) of macitentan and the metabolite-parent ratio (MR) displayed a significant decrease. Bergapten competitively inhibited macitentan metabolism in vitro and altered its pharmacokinetic characteristics in vivo. Further molecular docking analysis was also consistent with the experimental results. This study provides a reference for the combined use of bergapten and macitentan in clinical practice.

A distinction between Fritillaria Cirrhosa Bulbus and Fritillaria Pallidiflora Bulbus via LC-MS/MS in conjunction with principal component analysis and hierarchical cluster analysis

Fritillaria Cirrhosa Bulbus (known as chuanbeimu in Chinese, FCB) is one of the most used Chinese medicines for lung disease. However, a variety of substitutes have entered the market, with Fritillaria Pallidiflora Bulbus (FPB) being the most common. Due to their similarity in appearance, morphology, and chemical composition but a large price difference, the FCB has frequently been adulterated with the FPB, posing a serious challenge to the distinction and quality of the FCB. Therefore, we aimed to distinguish FCB and FPB based on their main nine isosteroidal alkaloid contents and test the potential of chemometrics as a discrimination approach for evaluating quality. The nine major isosteroidal alkaloids were measured using a liquid chromatography with tandem mass spectrometry (LC-MS/MS) approach in 41 batches of FCB and 17 batches of FPB. Additionally, they were categorized and distinguished using the methods of hierarchical cluster analysis (HCA) and principal component analysis (PCA). Quantitative analysis revealed that the nine alkaloids were present in different amounts in the two types of Fritillariae bulbus. In FCB, the highest amount was peimisine (17.92-123.53 μg/g) and the lowest was delavine (0.42-29.18 μg/g), while in FPB, imperialine was higher (78.05-344.09 μg/g), but verticinone and verticine were less than the other seven alkaloids. The FCB and FPB were successfully classified and distinguished by the HCA and PCA. Taken together, the method has a good linear relationship (R2 > 0.9975). The LOD and LOQ of the nine alkaloids were in the range of 0.0651-0.6510 and 0.1953-1.9531 ng/mL, respectively. The intra- and inter-day precision were shown to be excellent, with relative standard deviations (RSDs) below 1.63% and 2.39%, respectively. The LC-MS/MS method in conjunction with HCA and PCA can effectively differentiate FCB and FPB. It may be a promising strategy for quality evaluation and control at the FCB.

An in-depth analysis of four classes of antidepressants quantification from human serum using LC-MS/MS

Depression is a growing global crisis, with females at a higher rate of diagnosis than males. While the percentage of patients on prescribed antidepressants have tripled over the last two decades, we are still at a crossroad where the discrepancy lies between finding a drug to suit a patient and monitoring the abundance of it in the body to prevent unwanted side effects. Liquid Chromatography tandem mass spectrometry (LC-MS/MS) has garnered the attention of clinicians as a technique to accurately monitor therapeutic drugs in human serum with high specificity and accuracy. This may be a potential solution, but the challenge persists in the realm of sample preparation, where a method is automatable. We have developed and validated an LC-MS/MS-based assay for simultaneous quantification of 4 different classes of commonly prescribed antidepressants in women that is automated using a JANUS G3 Robotic Liquid Handler. Our method utilizes a simple sample preparation technique, utilizing only 20 μL of a serum sample, to accurately measure Bupropion, Citalopram, Desipramine, Imipramine, Olanzapine, Sertraline and Vilazodone across a range of 1.0 to 230 ng/mL. Our method exhibits a linearity of R2 ≥ 0.99 when detected in MRM mode and % CV of ≤ 20% for all analytes across the board. In addition, we have designed a prototype that can be utilized at a clinical mass spectrometry lab and assessed the long-term use of this prototype using an accelerated stability study. Overall, our developed method has the potential to be translated to clinical settings to monitor postpartum depression for a large number of patient samples using automation.

Development and validation of a stability-indicating high performance liquid chromatographic assay for determination of cariprazine in bulk form and in drug product

The aim of the present study is to develop a stability indicating high performance liquid chromatographic method for the determination of cariprazine in bulk substance and in drug product. The chromatographic separation was carried out using a Phenomenex Kinetex® C18 column (5μm, 250×4.6mm) and a mobile phase consisting of acetonitrile-potassium dihydrogen orthophosphate buffer (pH 4; 50mM) (30:70, v/v), at a flow rate of 1mlmin -1 and UV detection at 248nm. The column was maintained at 25°C and an injection volume of 20μL was used. Stress testing of cariprazine bulk substance and drug product was performed according to the International Conference on Harmonization (ICH) Q1A (R2) guideline. Various stress conditions were tested including acidic, alkaline and neutral hydrolysis, humidity, oxidation, dry heat and photolysis. A total of three degradation products (DPs) were formed. Among them two DPs were successfully characterized with the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis.

Preliminary verification of the anti-hypoxia mechanism of Gentiana straminea maxim based on UPLC-triple TOF MS/MS and network pharmacology

BACKGROUND

Anoxia is characterized by changes in the morphology, metabolism, and function of tissues and organs due to insufficient oxygen supply or oxygen dysfunction. Gentiana straminea Maxim (G.s Maxim) is a traditional Tibetan medicine. Our previous work found that G.s Maxim mediates resistance to hypoxia, and we found that the ethyl acetate extract had the best effect. Nevertheless, the primary anti-hypoxia components and mechanisms of action remain unclear.

METHODS

Compounds from the ethyl acetate extraction of G.s Maxim were identified using UPLC-Triple TOF MS/MS. Then Traditional Chinese Medicine Systematic Pharmacology Database was used to filtrate them. Network pharmacology was used to forecast the mechanisms of these compounds. Male specific pathogen-free Sprague Dawley rats were randomly divided into six groups: (1) Control; (2) Model; (3) 228 mg/kg body weight Rhodiola capsules; (4) 6.66 g/kg body weight the G.s Maxim's ethyl acetate extraction; (5) 3.33 g/kg body weight the G.s Maxim's ethyl acetate extraction; (6) 1.67 g/kg body weight the G.s Maxim's ethyl acetate extraction. After administering intragastric ally for 15 consecutive days, an anoxia model was established using a hypobaric oxygen chamber (7000 m, 24 h). Then Histology, enzyme-linked immunosorbent assays, and western blots were performed to determine these compounds' anti-hypoxic effects and mechanisms. Finally, we performed a molecular docking test to test these compounds using Auto Dock.

RESULTS

Eight drug-like compounds in G.s Maxim were confirmed using UPLC-Triple TOF MS/MS and Lipinski's rule. The tumor necrosis factor (TNF) signaling pathway, the hypoxia-inducible factor 1 (HIF-1) signaling pathway, and the nuclear factor kappa-B (NF-κB) signaling pathway was signaling pathways that G.s Maxim mediated anti-anoxia effects. The critical targets were TNF, Jun proto-oncogene (JUN), tumor protein p53 (TP53), and threonine kinase 1 (AKT1). Animal experiments showed that the ethyl acetate extraction of G.s Maxim ameliorated the hypoxia-induced damage of hippocampal nerve cells in the CA1 region and reversed elevated serum expression of TNF-α, IL-6, and NF-κ B in hypoxic rats. The compound also reduced the expression of HIF-1α and p65 and increased the Bcl-2/Bax ratio in brain tissue. These findings suggest that G.s Maxim significantly protects against brain tissue damage in hypoxic rats by suppressing hypoxia-induced apoptosis and inflammation. Ccorosolic acid, oleanolic acid, and ursolic acid had a strong affinity with core targets.

CONCLUSIONS

The ethyl acetate extraction of G.s Maxim mediates anti-hypoxic effects, possibly related to inhibiting apoptosis and inflammatory responses through the HIF-1/NF-κB pathway. The primary active components might be corosolic, oleanolic, and ursolic acids.

An ultra-performance LC-MS/MS method for determination of JRF103 in human plasma: application in first-in-patient study

Background: JRF103, a novel pan-HER inhibitor, has shown potent activity against HER1, HER2, HER4 and EGFR in vitro. To support its first-in-patient trial, a sensitive and rapid method was developed and validated using ultra-performance LC-MS/MS. Materials & methods: JRF103 was extracted from plasma using protein precipitation. Extracts were subjected to ultra-performance LC-MS/MS with electrospray ionization. Results: Separation of analyte was achieved using a 1.7-μm C₁₈ column (2.1 × 50-mm internal diameter) with a gradient elution. The developed method was fully validated following the international guides. Conclusion: The developed method was sensitive, specific and suitable for measuring JRF103 concentration in patients with advanced solid tumors in the first-in-patient study of JRF103.

Glutathione-Mediated Conjugation of Anticancer Drugs: An Overview of Reaction Mechanisms and Biological Significance for Drug Detoxification and Bioactivation

The effectiveness of many anticancer drugs depends on the creation of specific metabolites that may alter their therapeutic or toxic properties. One significant route of biotransformation is a conjugation of electrophilic compounds with reduced glutathione, which can be non-enzymatic and/or catalyzed by glutathione-dependent enzymes. Glutathione usually combines with anticancer drugs and/or their metabolites to form more polar and water-soluble glutathione S-conjugates, readily excreted outside the body. In this regard, glutathione plays a role in detoxification, decreasing the likelihood that a xenobiotic will react with cellular targets. However, some drugs once transformed into thioethers are more active or toxic than the parent compound. Thus, glutathione conjugation may also lead to pharmacological or toxicological effects through bioactivation reactions. My purpose here is to provide a broad overview of the mechanisms of glutathione-mediated conjugation of anticancer drugs. Additionally, I discuss the biological importance of glutathione conjugation to anticancer drug detoxification and bioactivation pathways. I also consider the potential role of glutathione in the metabolism of unsymmetrical bisacridines, a novel prosperous class of anticancer compounds developed in our laboratory. The knowledge on glutathione-mediated conjugation of anticancer drugs presented in this review may be noteworthy for improving cancer therapy and preventing drug resistance in cancers.

Comparative Pharmacokinetics of Cinobufacini Capsule and Injection by UPLC-MS/MS

Cinobufacini capsule and injection are two different formulations from the same source, obtained from the extraction of the skin of Bufo bufo gargarizans Cantor, which have been approved by the Chinese State Food and Drug Administration (CFDA) for the treatment of various cancers. Our previous study has found that the cinobufacini capsule and injection exhibited different anticancer effects, but their different pharmacokinetic behaviors, which could give a cause of that, have never been reported. So a sensitive and selective method for the simultaneous quantitation of 13 compounds in the rat plasma, including bufothionine, hellebrigenin, bufalin, gamabufotalin, telocinobufagin, cinobufagin, arenobufagin, cinobufotalin, desacetylcinobufotalin, bufotalin, pseudobufarenogin, resibufogenin, and desacetylcinobufagin, was established by using the Agilent 6460 mass spectrometer equipped with an ESI ion source in a multiple-reaction monitoring (MRM) mode. Chromatographic analysis was accomplished in 6 min by using an Agilent SB-C18 column and a mobile phase consisting of 0.1% formic acid in water and acetonitrile in an optimized gradient program at a flow rate of 0.3 ml/min. The correlation coefficients (r) of all analytes ranged from 0.9967 to 0.9996, while their lower limits of quantification ranged from 0.20 to 4.84 ng/ml. The method has been fully verified and applied for the pharmacokinetic difference study of the Cinobufacini capsule and injection in rats. The results showed that nine components could be quantitated in rat plasma samples after the administration of the cinobufacini capsule, while only bufothionine, bufalin, arenobufagin, and pseudobufarenogin could be detected in the cinobufacini injection group. Their pharmacokinetic studies indicated telocinobufagin, bufalin, desacetylcinobufagin, and arenobufagin were predicted as the potential active substances of the Cinobufacini capsule, while bufothionine was considered as a major ingredient in the cinobufacini injection due to its relatively high blood drug exposure. Also, the AUC of the nine components in cinobufacini capsule groups with three different doses showed a similar trend with significant differences, and the exposure increased with the increase of the dose. The pharmacokinetic characteristics of all major ingredients in cinobufacini capsules and injection were of wide variation, which could be used to explain differences in the efficacy of the cinobufacini capsule and injection and infer the pharmacodynamic ingredients of various cinobufacini preparations.

Identification of the major photodegradant in metronidazole by LC-PDA-MS and its reveal in compendial methods

Metronidazole in aqueous solution is sensitive to light and UV irradiation, leading to the formation of N-(2-hydroxyethyl)-5-methyl-l,2,4-oxadiazole-3-carboxamide. This is revealed here by liquid chromatography with tandem photo diode array detection and mass spectrometry (LC-PDA-MS) and further verified by comparison with the corresponding reference substance and proton nuclear magnetic resonance (¹H-NMR). However, in current compendial tests for related substances/organic impurities of metronidazole, the above photolytic degradant could not be detected. Thus, when photodegradation of metronidazole occurs, it could not be demonstrated. In our study, an improved LC method was developed and validated, which includes a detection at a wavelength of 230 nm and optimization of mobile phase composition thereby a better separation was obtained.

Active Compounds in Zingiber officinale as Possible Redox Inhibitors of 5-Lipoxygenase Using an In Silico Approach

5-Lipoxygenase (5-LOX) converts arachidonic acid to lipidic inflammatory mediators such as leukotrienes (LTs). In diseases such as asthma, LTs contribute to a physiopathology that could be reverted by blocking 5-LOX. Natural products with anti-inflammatory potential such as ginger have been used as nutraceuticals since ancient times. 6-Gingerol and 6-shogaol are the most abundant compounds in the ginger rhizome; they possess anti-inflammatory, antioxidant, and chemopreventive properties. In the present study, 6-gingerol and 6-shogaol structures were analyzed and compared with two commercial 5-LOX inhibitors (zileuton and atreleuton) and with other inhibitor candidates (3f, NDGA, CP 209, caffeic acid, and caffeic acid phenethyl ester (CAPE)). The pharmacokinetics and toxicological properties of 6-gingerol, 6-shogaol, and the other compounds were evaluated. Targeted molecular coupling was performed to identify the optimal catalytic pocket for 5-LOX inhibition. The results showed that 6-gingerol and 6-shogaol follow all of the recommended pharmacokinetic parameters. These compounds could be inhibitors of 5-LOX because they present specific interactions with the residues involved in molecular inhibition. The current study demonstrated the potential of 6-gingerol and 6-shogaol as anti-inflammatory agents that inhibit 5-LOX, as they present a high level of performance in the toxicological analysis and could be catabolized by the cytochrome p450 enzymatic complex; however, 6-gingerol was superior in safety compared to 6-shogaol.

Identification of promising nutraceuticals against filarial immune-modulatory proteins: insights from in silico and ex vivo studies

Lymphatic filariasis is a neglected tropical disease affecting over 863 million people in 47 countries of the world. The anti-filarial drugs, diethylcarbamazine, albendazole, and ivermectin, are effective only at the larval stages and have proven completely ineffective as adulticides. Besides this, a long-term use of these drugs is associated with several side effects including drug toxicity. Nutraceuticals have emerged as better alternatives for long term treatments due to their safety and lesser side effects. In the present work, we have used drug docking analysis and molecular dynamics simulation approaches to explore the effect of anti-inflammatory nutraceuticals against the immune-modulatory proteins of filarial worms. The filarial proteins enolase, ES-62 precursor, serpin, and cystatin, which are highly efficient in host immune modulation were targeted with more than 50 nutraceuticals. In the in silico study nutraceuticals such as naringin, β-carotene, and emodin showed higher binding efficacy and lower dissociation constant as compared to anti-filarial drugs. Molecular dynamics simulation results showed that immune-modulatory proteins formed highly stable complexes with naringin, β-carotene, and emodin over the entire MD simulation run. The nutraceutical emodin formed the most stable system in silico and hence its effect was investigated on adult filarial parasites under ex vivo conditions too. Emodin significantly affected the motility, viability, ROS production, and genomic DNA fragmentation of filarial parasites. Further in vivo and in vitro studies will help in understanding the mechanism of action of emodin at the molecular level and would help in the development of more effective anti-filarial drugs.

Here in drug docking analysis, molecular dynamics simulations and ex vivo approaches were used to demonstrate the anti-filarial effects of nutraceuticals against immune modulatory proteins of lymphatic filarial parasites.

Review on in vivo profiling of drug metabolites with LC-MS/MS in the past decade

Metabolite profiling is an indispensable part of drug discovery and development, enabling a comprehensive understanding of the drug's metabolic behavior. Liquid chromatography-mass spectrometry facilitates metabolite profiling by reducing sample complexity and providing high sensitivity. This review discusses the in vivo metabolite profiling involving LC-MS/MS and the utilization of QTOF, QQQ mass analyzers with a particular emphasis on a mass filter. Further, a summary of sample extraction procedures in biological matrices such as plasma, urine, feces, serum and hair as in vivo samples are outlined. toward the end, we present 15 case studies in biological matrices and their LC-MS/MS conditions to understand the metabolic disposition.

Infigratinib is a Reversible Inhibitor and Mechanism-based Inactivator of Cytochrome P450 3A4

Infigratinib (INF) is a promising selective inhibitor of fibroblast growth factor receptors 1-3 that has recently been accorded both orphan drug designation and priority review status by the U.S Food and Drug Administration for the treatment of advanced cholangiocarcinoma. Its propensity to undergo bioactivation to electrophilic species was recently expounded upon. However, other than causing aberrant idiosyncratic toxicities, these reactive intermediates may elicit mechanism-based inactivation (MBI) of cytochrome P450 enzymes (CYP450). In this study, we investigated the interactions between INF and the most abundant hepatic cytochrome P450 3A4 (CYP3A4). Our findings revealed that apart from being a potent noncompetitive reversible inhibitor of CYP3A4, INF inactivated CYP3A4 in a time-, concentration- and NADPH-dependent manner with K _I, k _inact and partition ratio of 2.45 µM, 0.053 min^-1 and 41 respectively when rivaroxaban was employed as the probe substrate. Co-incubation with testosterone (alternative CYP3A substrate) or ketoconazole (direct CYP3A inhibitor) attenuated the rate of inactivation whereas the inclusion of glutathione and catalase did not confer such protection. The lack of enzyme activity recovery following dialysis for 4 hours and oxidation with potassium ferricyanide, coupled with the absence of the characteristic Soret peak signature collectively substantiated that inactivation of CYP3A4 by INF was not mediated by the formation of quasi-irreversible metabolite-intermediate complexes but rather through irreversible covalent adduction to the prosthetic heme and/or apoprotein. Finally, glutathione trapping and high-resolution mass spectrometry experimental results unravelled two plausible bioactivation mechanisms of INF arising from the generation of a p-benzoquinone diimine and epoxide reactive intermediate. Significance Statement The potential of infigratinib (INF) to cause mechanism-based inactivation (MBI) of CYP3A4 was unknown. We report the reversible noncompetitive inhibition and irreversible covalent MBI of CYP3A4 by INF and proposed two potential bioactivation pathways implicating p-benzoquinone diimine and epoxide reactive intermediates. Findings from this study lay the groundwork for future investigation of clinically-relevant drug-drug interactions between INF and concomitant substrates of CYP3A4.

Identification and characterization of in vitro, in vivo, and reactive metabolites of tandutinib using liquid chromatography ion trap mass spectrometry

Tandutinib (TND) is a novel, oral small molecule designed for treating acute myeloid leukemia (AML) by inhibiting type III receptor tyrosine kinases. This study reports the use of in silico, in vivo, and in vitro methods to investigate the metabolism and possible metabolic bioactivation of TND. First, in silico metabolism of TND was assessed using the WhichP450™ module of the StarDrop® software to determine labile sites of metabolism in the TND chemical structure. Second, the XenoSite reactivity model, a web-based metabolism prediction software, was used to determine probable bioactive centers. Based on the in silico outcomes, a list of predicted metabolites and reactive intermediates were prepared. Third, in vitro and in vivo experiments were performed. In vitro TND metabolites were generated through incubation of TND with rat liver microsomes (RLMs). Another incubation of TND with RLMs was separately performed in the presence of GSH and KCN to check for the generation of reactive intermediates (soft and hard electrophiles). In vitro phase II metabolism was assessed by incubation of TND with isolated perfused rat hepatocytes. In vivo metabolism was investigated by oral gavage of TND (37 mg kg-1) in Sprague Dawley rats. Five in vitro phase I metabolites, one in vitro phase II and five reactive iminium intermediates (cyano adducts), six in vivo phase I, and one in vivo phase II metabolites of TND were characterized. The in vitro and in vivo metabolic pathways involved were O-dealkylation, α-hydroxylation, α-carbonyl formation, reduction, glucuronide, and sulfate conjugation. No GSH conjugate or its catabolic products were detected either in vitro or in vivo. Two cyclic tertiary rings of TND (piperazine and piperidine) were metabolically bioactivated to generate reactive iminium intermediates forming cyano adducts with KCN. The formed reactive intermediates may be the reason behind TND toxicity. In silico toxicological studies were performed for TND and its related (in vitro and in vivo) metabolites were evaluated using the DEREK software tool.

Galeon: A Biologically Active Molecule with In Silico Metabolite Prediction, In Vitro Metabolic Profiling in Rat Liver Microsomes, and In Silico Binding Mechanisms with CYP450 Isoforms

Galeon, a natural cyclic-diarylheptanoid (CDH), which was first isolated from Myrica gale L., is known to have potent cytotoxicity against A549 cell lines, anti-tubercular activity against Mycobacterium tuberculosis H37Rv, chemo-preventive potential, and moderate topoisomerase inhibitory activity. Here, in silico metabolism and toxicity prediction of galeon by CYP450, in vitro metabolic profiling study in rat liver microsomes (RLMs), and molecular interactions of galeon-CYP450 isoforms were performed. An in silico metabolic prediction study showed demethyl and mono-hydroxy galeon were the metabolites with the highest predictability. Among the predicted metabolites, mono-hydroxy galeon was found to have plausible toxicities such as skin sensitization, thyroid toxicity, chromosome damage, and carcinogenicity. An in vitro metabolism study of galeon, incubated in RLMs, revealed eighteen Phase-I metabolites, nine methoxylamine, and three glutathione conjugates. Identification of possible metabolites and confirmation of their structures were carried out using ion-trap tandem mass spectrometry. In silico docking analysis of galeon demonstrated significant interactions with active site residues of almost all CYP450 isoforms.

In Vivo Metabolism of Aristolochic Acid I and II in Rats Is Influenced by Their Coexposure

The plant extract aristolochic acid (AA), containing aristolochic acid I (AAI) and II (AAII) as major components, causes aristolochic acid nephropathy and Balkan endemic nephropathy, unique renal diseases associated with upper urothelial cancer. Differences in the metabolic activation and detoxification of AAI and AAII and their effects on the metabolism of AAI/AAII mixture in the plant extract might be of great importance for an individual's susceptibility in the development of AA-mediated nephropathies and malignancies. Here, we investigated in vivo metabolism of AAI and AAII after ip administration to Wistar rats as individual compounds and as AAI/AAII mixture using high performance liquid chromatography/electrospray ionization mass spectrometry. Experimental findings were supported by theoretical calculations using density functional theory. We found that exposure to AAI/AAII mixture affected the generation of their oxidative and reductive metabolites formed during Phase I biotransformation and excreted in rat urine. Several Phase II metabolites of AAI and AAII found in the urine of exposed rats were also analyzed. Our results indicate that AAI is more efficiently metabolized in rats in vivo than AAII. Whereas AAI is predominantly oxidized during in vivo metabolism, its reduction is the minor metabolic pathway. In contrast, AAII is mainly metabolized by reduction. The oxidative reaction only occurs if aristolactam II, the major reductive metabolite of AAII, is enzymatically hydroxylated, forming aristolactam Ia. In AAI/AAII mixture, the metabolism of AAI and AAII is influenced by the presence of both AAs. For instance, the reductive metabolism of AAI is increased in the presence of AAII while the presence of AAI decreased the reductive metabolism of AAII. These results suggest that increased bioactivation of AAI in the presence of AAII also leads to increased AAI genotoxicity, which may critically impact AAI-mediated carcinogenesis. Future studies are needed to explain the underlying mechanism(s) for this phenomenon.

Metabolic stability studies of lead compounds supported by separation techniques and chemometrics analysis

With metabolism being one of the main routes of drug elimination from the body (accounting for removal of around 75% of known drugs), it is crucial to understand and study metabolic stability of drug candidates. Metabolically unstable compounds are uncomfortable to administer (requiring repetitive dosage during therapy), while overly stable drugs increase risk of adverse drug reactions. Additionally, biotransformation reactions can lead to formation of toxic or pharmacologically active metabolites (either less-active than parent drug, or even with different action). There were numerous approaches in estimating metabolic stability, including in vitro, in vivo, in silico, and high-throughput screening to name a few. This review aims at describing separation techniques used in in vitro metabolic stability estimation, as well as chemometric techniques allowing for creation of predictive models which enable high-throughput screening approach for estimation of metabolic stability. With a very low rate of drug approval, it is important to understand in silico methods that aim at supporting classical in vitro approach. Predictive models that allow assessment of certain biological properties of drug candidates allow for cutting not only cost, but also time required to synthesize compounds predicted to be unstable or inactive by in silico models.

Investigation of Clozapine and Olanzapine Reactive Metabolite Formation and Protein Binding by Liquid Chromatography-Tandem Mass Spectrometry

Drug-induced toxicity has, in many cases, been linked to oxidative metabolism resulting in the formation of reactive metabolites and subsequent covalent binding to biomolecules. Two structurally related antipsychotic drugs, clozapine (CLZ) and olanzapine (OLZ), are known to form similar nitrenium ion reactive metabolites. CLZ-derived reactive metabolites have been linked to agranulocytosis and hepatotoxicity. We have studied the oxidative metabolism of CLZ and OLZ as well as two known metabolites of CLZ, desmethyl-CLZ (DCLZ), and CLZ-N-oxide (CLZ-NO), using in vitro rat liver microsomal (RLM) incubations with glutathione (GSH) trapping of reactive metabolites and liquid chromatography-high resolution tandem mass spectrometry (LC-HRMS/MS). Reactive metabolite binding to selected standard peptides and recombinant purified human proteins was also evaluated. Bottom-up proteomics was performed using two complementary proteases, prefractionation of peptides followed by LC-HRMS/MS for elucidating modifications of target proteins. Induced RLM was selected to form reactive metabolites enzymatically to assess the complex profile of reactive metabolite structures and their binding potential to standard human proteins. Multiple oxidative metabolites and several different GSH adducts were found for CLZ and OLZ. Modification sites were characterized on human glutathione S-transferase (hGST) alpha 1 (OLZ-modified at Cys112), hGST mu 2 (OLZ at Cys115), and hGST pi (CLZ, DCLZ, CLZ-NO and OLZ at Cys170), human microsomal GST 1 (hMGST1, CLZ and OLZ at Cys50), and human serum albumin (hSA, CLZ at Cys34). Furthermore, two modified rat proteins, microsomal GST 1 (CLZ and OLZ at Cys50) and one CYP (OLZ-modified, multiple possible isoforms), from RLM background were also characterized. In addition, direct effects of the reactive metabolite modifications on proteins were observed, including differences in protease cleavage specificity, chromatographic behavior, and charge-state distributions.