Mimicking of phase I metabolism reactions of molindone by HLM and photocatalytic methods with the use of UHPLC-MS/MS

Establishing the metabolism pathway of the drug undergoing the hepatic biotransformation pathway is one of the most important aspects in the preclinical discovery process since the presence of toxic or reactive metabolites may result in drug withdrawal from the market. In this study, we present the structural elucidation of six, not described yet, metabolites of an antipsychotic molecule: molindone. The elucidation of metabolites was supported with a novel photocatalytical approach with the use of WO3 and WS2 assisted photochemical reactions. An UHPLC-ESI-Q-TOF combined system was used for the registration of all obtained metabolite profiles as well as to record the high resolution fragmentation spectra of the observed transformation products. As a reference in the in vitro metabolism simulation method, the incubation with human liver microsomes was used. Chemometric comparison of the obtained profiles pointed out the use of the WO3 approach as being more convenient in the field of drug metabolism studies. Moreover, the photocatalysis was used in the direction of the main drug metabolite synthesis in order to further isolation and characterization

New hybrids of tacrine and indomethacin as multifunctional acetylcholinesterase inhibitors

A new series of hybrid compounds were designed, consisting of anti-AChE and BuChE activity components with an antiinfammatory component. A series of 9-amino-1,2,3,4-tetrahydroacridine and indomethacin derivatives were synthesized. All compounds were created using alkyldiamine with diferent chain lengths as a linker. Various biological activities were evaluated, including inhibitory activity against AChE and BuChE. The tested compounds showed high inhibitory activities against cholinesterases. The IC50 values for all compounds ranging from 10 nM to 7 µM. The potency of inhibition was much higher than well-known AChE and BuChE inhibitors (tacrine and donepezil). Compound 3h had the strongest inhibitory activity; kinetic studies showed it to have a mixed-type of acetylcholinesterase inhibition properties. The cytotoxicity of the newly-synthesized compounds against HepG2 (hepatocarcinoma cells) and EA.hy96 (human vein endothelial cells) cell lines was determined using the MTT and MTS tests. All investigated compounds presented similar cytotoxic activity against HepG2 and EA.hy926 cell line, ranged in micromolar values. Compounds with longer linkers showed higher antioxidant activity. The most active compound was 3h. Docking studies confrmed interactions with important regions of AChE and BuChE. Its multifunctional properties, i.e. high activity against AChE and BuChE, antioxidant activity and low cytotoxicity, highlight 3h as a promising agent for the treatment of AD

New tetrahydroacridine hybrids with dichlorobenzoic acid moiety demonstrating multifunctional potential for the treatment of Alzheimers disease

A series of new tetrahydroacridine and 3,5-dichlorobenzoic acid hybrids with different spacers were designed, synthesized, and evaluated for their ability to inhibit both cholinesterase enzymes. Compounds 3a, 3b, 3f, and 3g exhibited selective butyrylcholinesterase (EqBuChE) inhibition with IC50 values ranging from 24 to 607 nM. Among them, compound 3b was the most active (IC50 = 24 nM). Additionally, 3c (IC50 for EeAChE = 25 nM and IC50 for EqBuChE = 123 nM) displayed dual cholinesterase inhibitory activity and was the most active compound against acetylcholinesterase (AChE). Active compound 3c was also tested for the ability to inhibit Aβ aggregation. Theoretical physicochemical properties of the compounds were calculated using ACD Labs Percepta and Chemaxon. A Lineweaver-Burk plot and docking study showed that 3c targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Moreover, 3c appears to possess neuroprotective activity and could be considered a free-radical scavenger. In addition, 3c did not cause DNA damage and was found to be less toxic than tacrine after oral administration; it also demonstrated little inhibitory activity towards hyaluronidase (HYAL), which may indicate that it possesses anti-inflammatory properties. The screening for new in vivo interactions between 3c and known receptors was realized by yeast three-hybrid technology (Y3H)

The 42nd Symposium Chromatographic Methods of Investigating Organic Compounds : Book of abstracts

The 42nd Symposium Chromatographic Methods of Investigating Organic Compounds : Book of abstracts. June 4-7, 2019, Szczyrk, Polan

Photodegradation Study of Sertindole by UHPLC-ESI-Q-TOF and Influence of Some Metal Oxide Excipients on the Degradation Process

The evaluation of the influence of the excipients present in the pharmaceutical formulations on the drug stability is an important part of quality control of medicines. One of the most commonly applied group of excipients are pigments, such as titanium dioxide or various forms of iron oxides, which are well-known photocatalytic agents. Therefore, the photostability of an atypical antipsychotic drug sertindole and the influence of pigments commonly used in the pharmaceutical formulations (FeOOH, Fe2O3, and TiO2) on this process were studied. The quantitative and qualitative analysis of the process was performed with the use of ultra high pressure liquid chromatography with diode array detection (UHPLC-DAD) system coupled with a high resolution hybrid electrospray ionization quadrupole time-of-flight (ESI-Q-TOF) mass spectrometer. Sertindole turned out to be a highly photolabile molecule. Overall 18 transformation products were found, mainly formed as a consequence of dechlorination, hydroxylation, and dehydrogenation. In all the experiments, except the TiO2-mediated photocatalysis, the product of chlorine substitution with a hydroxyl group was the major product. The presence of Fe2O3 and TiO2 accelerated the degradation process, while FeOOH served as its inhibitor. The experiments conducted with the use of the pharmaceutical formulations confirmed the catalytic activity of the used excipients. The exploration of the obtained phototransformation profiles with the use of principal component analysis (PCA) revealed that the presence of both iron oxides could influence the qualitative and quantitative aspect of the studied processes. In silico assessment of the properties showed that the transformation products are generally less toxic to rodents, possess lower hERG blocking potential, but could be more mutagenic than the parent molecule

Characterization of Phase I Hepatic Metabolites of Anti-Premature Ejaculation Drug Dapoxetine by UHPLC-ESI-Q-TOF

Determination of the metabolism pathway of xenobiotics undergoing the hepatic pass is a crucial aspect in drug development since the presence of toxic biotransformation products may result in significant side effects during the therapy. In this study, the complete hepatic metabolism pathway of dapoxetine established according to the human liver microsome assay with the use of a high-resolution LC–MS system was described. Eleven biotransformation products of dapoxetine, including eight metabolites not reported in the literature so far, were detected and identified. N-dealkylation, hydroxylation, N-oxidation and dearylation were found to be the main metabolic reactions for the investigated xenobiotic. In silico analysis of toxicity revealed that the reaction of didesmethylation may contribute to the increased carcinogenic potential of dapoxetine metabolites. On the other hand, N-oxidation and aromatic hydroxylation biotransformation reactions possibly lead to the formation of mutagenic compounds

Photocatalysis as a Tool for in Vitro Drug Metabolism Simulation: Multivariate Comparison of Twelve Metal Oxides on a Set of Twenty Model Drugs

The constant development in the area of medicinal substances on the market and their subsequent progress in the field of drug analysis has become one of the reasons for the search for alternative, cheaper, and faster methods to determine the metabolism pathways of new molecular entities (NMEs). The simulation of transformation processes using photocatalysis is considered to be one of the promising methods. Although its effectiveness has been proven, the research has so far focused especially on titanium dioxide, while a more accurate comparison of the suitability of different photocatalysts in terms of their use in drug metabolism studies has not been performed. For this purpose, a set of twelve metal oxides was prepared and their photocatalytic efficiency in the direction of drug metabolism mimicking was checked on a model mixture of twenty medicinal substances differing both in chemical structure and pharmacological properties. Incubation with human liver microsomes (HLMs) was used as the reference method. The metabolic profiles obtained with the use of LC-MS analysis were compared using multidimensional chemometric techniques; and the graphic presentation of the results in the form of PCA plot and cluster dendrogram enabled their detailed interpretation and discussion. All tested photocatalysts confirmed their effectiveness. However, the exact outcome of the study indicate advantage of the WO3-assisted photocatalysis over other metal oxides

Characterization of forced degradation products of toloxatone by LC-ESI-MS/MS

Forced degradation of toloxatone in solutions under basic, acidic, neutral, photo UV–VIS, photo UVC and oxidative stress conditions was investigated and structural elucidation of its degradation products was performed with the use of UHPLC system coupled ESI-Q-TOF mass spectrometer. Eight degradation products were found and their masses and formulas were obtained with high accuracy (0.09–3.79 ppm). The structure of unknown degradation products were elucidated from MS/MS fragmentation spectra of all analyzed compounds. Additionally, whole signals of decomposed substances were compared chemometrically. It was found that toloxatone is fragile towards basic hydrolysis, oxidative conditions and UVC irradiation. Finally, the toxicity of transformation products was computationally evaluated and compared in multivariate manner. Keywords: Q-TOF, Mass spectrometry, UHPLC, Photodegradation, Toxicit

Multivariate Chemometric Comparison of Forced Degradation and Electrochemical Oxidation LC–MS Profiles of Maraviroc

In this study, nine forced degradation products of maraviroc were found using chemometric analysis. This antiretroviral drug was subjected to photolytic, oxidative, as well as neutral, basic and acidic hydrolysis stress conditions. Additionally, its electrochemical transformation on platinum, gold and glassy carbon screen-printed electrodes was examined. This study showed that maraviroc is especially susceptible to UVA, H2O2 and electrochemical degradation, while being resistant to neutral and acidic hydrolysis. A cluster analysis showed that the electrochemical transformation, with particular reference to the platinum electrode, is able to partially simulate the forced degradation processes, especially in the context of redox reactions. These findings indicate that the electrochemical methods can be considered as quick and relatively low-cost supplements to the commonly applied forced degradation procedures

Identification of the New Metabolite of Nebivolol Using Liquid Chromatography Coupled with High-Resolution Mass Spectrometry and Chemometrics

In this study, the phase I hepatic metabolism pathway of a cardiovascular drug nebivolol was proposed on the basis of a human liver microsomes assay with the use of LC-HR-MS coupled with the chemometric method. Six biotransformation products were found with the assistance of chemometric analysis. Five of them were identified as the previously reported products of alicyclic hydroxylation and dihydroxylation, aromatic hydroxylation, as well as alicyclic oxidation of the parent compound. Moreover, one metabolite, not reported so far, was found to be a product of N-dealkylation of nebivolol—2-amino-1-(6-fluoro-3,4-dihydro-2H-1-benzopyran-2-yl)ethan-1-ol. The novel metabolite was submitted to an in silico toxicity analysis to assess its biological properties. The applied computational methods indicated a significantly elevated risk of its mutagenic activity, compared to the parent molecule. Several metabolites of the nebivolol described in the literature were not detected in this study, indicating their non-hepatic origin