Clozapine Interaction Research Articles

Molecular Docking Study of Various Protein on Clozapine

The antipsychotic drug Clozapine is widely recognized for its efficacy in treating resistant schizophrenia. This study aims to elucidate the binding interactions of Clozapine with four key proteins: 1GQ1, 1MKF, 4OAJ, and 7WU2. These proteins represent diverse biological targets, including receptors and enzymes relevant to neurological function and drug metabolism. Utilizing molecular docking simulations, we compared the binding affinities and interaction profiles of Clozapine with these proteins.

Schizophrenia Animal Modeling with Epidermal Growth Factor and Its Homologs: Their Connections to the Inflammatory Pathway and the Dopamine System.

Epidermal growth factor (EGF) and its homologs, such as neuregulins, bind to ErbB (Her) receptor kinases and regulate glial differentiation and dopaminergic/GABAergic maturation in the brain and are therefore implicated in schizophrenia neuropathology involving these cell abnormalities. In this review, we summarize the biological activities of the EGF family and its neuropathologic association with schizophrenia, mainly overviewing our previous model studies and the related articles. Transgenic mice as well as the rat/monkey models established by perinatal challenges of EGF or its homologs consistently exhibit various behavioral endophenotypes relevant to schizophrenia. In particular, post-pubertal elevation in baseline dopaminergic activity may illustrate the abnormal behaviors relevant to positive and negative symptoms as well as to the timing of this behavioral onset. With the given molecular interaction and transactivation of ErbB receptor kinases with Toll-like receptors (TLRs), EGF/ErbB signals are recruited by viral infection and inflammatory diseases such as COVID-19-mediated pneumonia and poxvirus-mediated fibroma and implicated in the immune-inflammatory hypothesis of schizophrenia. Finally, we also discuss the interaction of clozapine with ErbB receptor kinases as well as new antipsychotic development targeting these receptors.

Hirshfeld surface and electrostatic potential surface analysis of clozapine and its solubility and molecular interactions in aqueous blends

Solubility and relevant thermodynamic properties as well as molecular interactions of clozapine in aqueous systems of protic cosolvent, e.g. isopropanol, and aprotic cosolvents such as acetonitrile, dimethyl sulfoxide (DMSO) and N-methyl-2-pyrrolidinone (NMP) are focus of this paper. The intermolecular interactions and overall charge distribution of clozapine were respectively investigated by using Hirshfeld surface analysis and molecular electrostatic potential surface. All experimentations were executed using a shake-flask approach under p = 101.2 kPa (local pressure) from 278.15 (293.15) to 323.15 (333.15) K. The minimum solubility data of clozapine appeared in neat water for each aqueous system at 278.15 K; and the maximum one, in neat cosolvent at 328.15 K. Correlation of the solubility data (mole fraction) through Jouyban–Acree and MRS models acquired acceptable results with relative average deviations (RAD) of no>9.15 %. The solvent descriptors of hydrogen-bonding basicity, solubility parameter and dipolarity-polarizability predominantly controlled the clozapine solubility variation through the quantitative analysis of linear solvation energy relationships in terms of the solubility data at 298.15 K. The extended Hildebrand solubility approach was also employed here to correlate the solubility and study the solvation behavior of solutions. Quantitatively analysis of preferential solvation of clozapine by solvent species in solutions was conducted by the method of inverse Kirkwood–Buff integrals. In the solutions with middle and cosolvent-rich compositions, the parameters of preferential solvation for DMSO, NMP, acetonitrile or isopropanol were positive, which specified that preferential solvation of clozapine was made by co-solvent. In addition, the thermodynamic properties of dissolution of clozapine along with enthalpy–entropy compensation were derived and deeply discussed.

Neutrophil Myeloperoxidase-Mediated N-Demethylation of Quetiapine Leads to N-Desalkylquetiapine, a Pharmacologically Active Cytochrome P450 Metabolite

The atypical antipsychotic drugs, quetiapine and clozapine, are associated with idiosyncratic drug reactions (such as agranulocytosis or neutropenia) that are thought to involve reactive metabolites. Neutrophil myeloperoxidase (MPO) metabolism of quetiapine is not well-studied, but is metabolized by cytochrome P450. Based on structural similarity to clozapine, we hypothesized that quetiapine can be metabolized by MPO and that there is overlap between cytochrome P450 and MPO metabolism of quetiapine. The interaction of quetiapine and clozapine with MPO and MPO chlorination activity was studied using UV-vis spectrophotometry. The metabolites were characterized using liquid chromatography-mass spectrometry (LC-MS), and electron paramagnetic resonance (EPR) spectroscopy was used for detecting drug-catalyzed glutathione oxidation. In the presence of quetiapine, MPO compound II accumulated for about 7.5 min, whereas in the presence of clozapine, MPO compound II was not observed as it was rapidly reduced back to the resting state. Increasing quetiapine concentrations resulted in a decrease in MPO chlorination activity, while the opposite result was found in the case of clozapine. UV-vis spectral studies showed no change when quetiapine was oxidized in the absence and presence of chloride anion (Cl-, to catalyze chlorination reactions). Significant changes, however, were observed in the same assay with clozapine, where Cl- appeared to hinder the rate of clozapine metabolism. The MPO-catalyzed hydroxylated and dealkylated metabolites of quetiapine and hydroxylated metabolites of clozapine were observed from the LC-MS analyses, particularly when Cl- was included in the reaction. In addition, hydroxylated, dealkylated, and a proposed sulfoxide metabolite of quetiapine were also observed in the reaction catalyzed by human microsomes/NADPH. Lastly, compared to quetiapine, clozapine metabolism by MPO/H2O2 and glutathione produced more glutathionyl radicals using EPR spin trapping. In conclusion, MPO/H2O2/Cl- was shown to metabolize quetiapine to S-oxidation and P450-like dealkylation products, and quetiapine metabolites were generally less reactive than clozapine.

Clozapine and Neutropenia in Patients with Schizophrenia and SARS-CoV-2 Infection.

BackgroundClozapine (CLZ) is used for treatment-resistant schizophrenia (TRS). Adverse reactions to clozapine include neutropenia. In March 2020, WHO declared the COVID-19 pandemic and after, psychiatrists raised concerns regarding continuation of clozapine, due to multiple restrictions. We aimed to provide a study on the association between neutropenia and clozapine in patients with schizophrenia and COVID-19.AimTo assess the neutrophil count in patients with schizophrenia treated with clozapine and infected with COVID-19.MethodsThe study patients with schizophrenia, according to DSM-5, admitted to the Clinical Hospital of Psychiatry and Neurology Brasov, Romania, between April 2020 and October 2021. The inclusion criteria included positive RT-PCR (real-time PCR) test for COVID-19 and treatment with clozapine. We assessed three values of ANC (absolute neutrophil count): before COVID-19 infection (last ANC obtained at mandatory check), during infection and 1 month after resolution (first negative PCR test).ResultsOf the 105 cases, 95 did not have neutropenia. Fifty-nine patients were males (62.1%), mean age was 43.5 years (SD = 12.1) with an average of clozapine treatment of 52.4 months (SD = 11.9). At baseline, they had a small reduction in the ANC mean value (4.41 × 109/l; SD = 2.22) which did not constitute a statistically significant decline from the prior to COVID-19 mean value of 4.66 × 109/l (SD = 2.34; p = 0.45). Values were also normal in the first month after negative PCR testing (4.45 × 109/l; SD = 2.35; p = 0.91). A total of 10 patients (9.5%) had neutropenia. The age, dose of clozapine and duration of treatment were not statistically different compared to the group without neutropenia.ConclusionPsychiatrists and other health professionals should keep in mind that neutrophil count may decrease during COVID-19 infection in patients taking clozapine and in some cases, neutropenia may even occur. We assumed that neutropenia could be caused by COVID-19 and clozapine interaction.

Interaction of clozapine with metformin in a schizophrenia rat model

The low efficacy of antipsychotic drugs (e.g., clozapine) for negative symptoms and cognitive impairment has led to the introduction of adjuvant therapies. Because previous data suggest the procognitive potential of the antidiabetic drug metformin, this study aimed to assess the effects of chronic clozapine and metformin oral administration (alone and in combination) on locomotor and exploratory activities and cognitive function in a reward-based test in control and a schizophrenia-like animal model (Wisket rats). As impaired dopamine D1 receptor (D1R) function might play a role in the cognitive dysfunctions observed in patients with schizophrenia, the second goal of this study was to determine the brain-region-specific D1R-mediated signaling, ligand binding, and mRNA expression. None of the treatments affected the behavior of the control animals significantly; however, the combination treatment enhanced D1R binding and activation in the cerebral cortex. The Wisket rats exhibited impaired motivation, attention, and cognitive function, as well as a lower level of cortical D1R binding, signaling, and gene expression. Clozapine caused further deterioration of the behavioral parameters, without a significant effect on the D1R system. Metformin blunted the clozapine-induced impairments, and, similarly to that observed in the control animals, increased the functional activity of D1R. This study highlights the beneficial effects of metformin (at the behavioral and cellular levels) in blunting clozapine-induced adverse effects.

Clozapine interaction

Clozapine interaction

Ciprofloxacin and Clozapine Interaction in a Patient Requiring Intensive Care

Ciprofloxacin and Clozapine Interaction in a Patient Requiring Intensive Care

Analysis of clozapine in its tablets using two novel spectrophotometric reactions targeting its tertiary amino group.

Two simple spectrophotometric methodologies have been proposed and validated for the measurement of an atypical antipsychotic drug Clozapine (CLZ). Method A depends on interaction of CLZ with N-bromosuccinimide(NBS) resulting in formation of a yellowish orange colored product, measured at 320nm. The linearity range was 5.0-70.0μg/mL. Method B depends on condensation of the same drug with acetic acid mixed anhydride reagent producing a purple colored product, measured at 319nm. The linearity range was 8.0-24.0μg/mL. All parameters affecting the reaction condition (volume of both reagent, temperature, time and the different diluting solvents) were optimized. Both methods were successfully applied to assay CLZ in its pure form and tablets giving mean percentage recoveries of (98.87±1.8 and 100±1.7) for method A, and corresponding values of (98.6±0.96 and 99.5±1) for method B. Besides, the study of reactions stoichiometry was performed and the reaction mechanisms were proposed.

Complex drug interaction of carbamazepine, fluvoxamine and clozapine in a patient with bipolar depression

Complex drug interaction of carbamazepine, fluvoxamine and clozapine in a patient with bipolar depression

The interaction of clozapine loaded nanocapsules with the hCMEC/D3 cells – In vitro model of blood brain barrier

Despite progress in the development of novel pharmacological compounds, their efficacy in the treatment of neuropathologies is not satisfactory. One strategy to achieve safe and efficient brain targeting therapy is to design nanocarriers capable of transporting antipsychotic drugs through the BBB (without affecting the normal functions of the barrier) in a defined part of the brain. Here we investigate the interaction of clozapine-loaded polymeric Nano capsules (CLO-NCs) with hCMEC/D3 (human cerebral microvascular endothelial cells, D3 clone) cells that constitutes an in vitro model of the blood brain barrier (BBB). CLO-NCs (average size of 100nm) were constructed by the technique of sequential adsorption of polyelectrolytes (LbL), using biocompatible polyanion PGA (Poly-l-glutamic acid sodium salt) and polycation PLL (poly L-lysine) on clozapine-loaded nano-emulsion cores. Pegylated external layers were prepared using PGA-g(39)-PEG (PGA grafted by PEG poly(ethylene glycol)). The influence of the physicochemical properties of the CLO-NCs (charge, size, surface modification) on cell viability was determined. Advanced studies of CLO-NCs internalization (including endocytosis and transcytosis experiments) using confocal microscopy, flow cytometry and fluorescence spectroscopy are presented. Our results indicate that among the studied NCs, the pegylated clozapine-loaded NCs were the most protected from their uptake by macrophages, and they were the least toxic to hCMEC/D3 cells. They were also the most efficient in the transcytosis experiment, which serves as an indicator of their ability to cross a model BBB.

Molecularly imprinted polymer microprobes for manipulating neurological function by regulating temperature-dependent molecular interactions

We describe molecularly imprinted polymer (MIP) microprobes for manipulating neurological function by the thermoregulatory process. Some target and disease areas show raised temperature than normal temperature which are involved in neuronal diseases, such as Alzheimer’s, Parkinson’s and Huntington’s diseases. As well thermodynamic parameters can be obtained in the environments in vitro, which that the assay involves a temperature variable, at or beyond body temperature. We applied for studying molecular aspects of hypothalamus regulated physiology and behaviors. Steady-state binding was detected by fluorescence and Boltzmann energies-based fluorescence emission showed interactions of clozapine with altered energy levels. Dynamic spectra revealed dramatic effects on the fluorescence of the drug in dopamine imprint of MIPs exposed rat hypothalamic membranes at different temperatures. The MIPs that cooperatively occupied and provided the response to the neural proteins were not likely to be involved in the binding of clozapine within the cavity. The results indicated that the dynamics on the surface of proteins exposed to the drug–MIP with assembly, mediated specific function through temperature-dependent molecular interaction in the hypothalamus. Thus, this approach is applicable to processes of key importance of controlling the energy homeostasis and, plausibly, to selective signaling can affect in plasticity of the neural response.

Clozapine, An Atypical Antipsychotic, Reduces The Contribution Of Brown Adipose Tissue (BAT) To Emotional Hyperthermia In Rats

Clozapine is an atypical antipsychotic drug used in patients with schizophrenia. Animal models of clozapine's actions are difficult to develop. BAT thermogenesis is increased by 5‐HT2A receptor activation and decreased by 5‐HT1A receptor activation in the CNS. Clozapine's interaction with these receptors predicts that the drug reduces BAT thermogenesis. We tested this in animal model in which BAT thermogenesis is initiated in a resident rat by introduction of an intruder rat confined to a small cage (Mohammed et al., 2012). ) Thermistor probes, connected to a headpiece, were placed in anterior mediastinum and interscapular BAT of anesthetized male Sprague‐Dawley rats (350‐450g. After 1 week the rat was maintained in a quiet, temperature controlled environment with ad libitum food and water. BAT and body temperatures were monitored via a swivel device. Clozapine was administered (0.03, 0.125, 0.5 and 2 mg/kg in 0.5 ml of acidified Ringer via subcutaneous catheter) and 30 min later the caged intruder was introduced for 30 min. At the lowest clozapine dose, the increase in BAT temperature (0.8±0.1C°) was greater (P<0.01) than the increase in body temperature (0.5±0.1C°). Clozapine, in a dose‐responsive manner, reduced the increase in BAT and body temperatures elicited during sudden confrontation with an intruder rat (log‐dose regression P<0001, R2 = 0.52, for BAT and P<0.01, R2 = 0.32 for body). Thus clozapine reduces BAT thermogenesis initiated by salient, threatening environmental events, thereby reducing emotional hyperthermia. BAT thermogenesis occurs in adult humans, possibly excessively in schizophrenics, so that our animal model may illuminate clozapine's therapeutic action and its contribute to obesity.Supported by NHMRC

P.3.b.034 Interaction of EAAT2 genotype and clozapine on cognitive remediation outcome

P.3.b.034 Interaction of EAAT2 genotype and clozapine on cognitive remediation outcome

Kinetics of Drug Interaction with the Kv11.1 Potassium Channel

The Kv11.1 potassium channel is the molecular target for the majority of drugs implicated in acquired long QT syndrome, the most common cause of drug-induced sudden cardiac death, and a common reason for drug restriction or withdrawal from the market. While the IC50 for block of Kv11.1 is commonly used to estimate the risk of acquired long QT syndrome, this approach is crude, and it is widely accepted that the kinetics of drug interactions with the channel are a critical component in understanding their mechanism of action and risk profiles. In this study we report the first directly measured kinetics of block and unblock of Kv11.1 by a QT prolonging drug: the antipsychotic clozapine. Our data show that clozapine binding to Kv11.1 is complex. There are at least two kinetically distinct components to both block and unblock, while the kinetics of unblock are dependent on the dose or duration of drug application. Based on these observations, we have proposed a model incorporating kinetically distinct binding to the open and inactivated states of Kv11.1 that can describe the observed kinetic features of clozapine block and correctly predict the overall affinity and apparent nonstate-dependent interaction of clozapine with Kv11.1. Mechanistic insights into drug block of Kv11.1 gained though detailed kinetic analyses such as this have a potential role in development of drugs targeted to specific channel states to reduce unwanted side effects, as well as in the design of better high-throughput preclinical tests for assessing the proarrhythmic effects of QT prolonging drugs.

Factors affecting interindividual differences in clozapine response: a review and case report

Clozapine is the most powerful new‐generation antipsychotic. Although this drug leads to great therapeutic benefits, two types of undesirable conditions frequently occur with its use: side effects and resistance to treatment. Therapeutic drug monitoring of clozapine would be very useful to avoid both these situations. The necessity of monitoring the therapy is the result of a wide interindividual variability in the metabolism of clozapine. In this review, we highlight all the conditions underlying this variability, analyzing them one by one. Relevant literature was identified through a search of MEDLINE and PubMed. In addition, the case of a treatment‐resistant patient with accelerated metabolism of clozapine is reported as representative of utility of therapeutic drug monitoring in terms of clozapine dose adjustment. Genetic polymorphisms of cytochrome P450 enzymes and of neurotransmitter receptors; drug interactions; interactions of clozapine with other substances such as food and drink; smoking; and nonmodifiable variables such as age, ethnicity, and gender have been examined in relation to the existing scientific literature. The laboratory techniques that clinicians could use to identify these variables and adequate therapies are also reviewed.

Interaction of clozapine and its nitrenium ion with rat D2 dopamine receptors: in vitro binding and computational study

The interaction of diazepine analogues like clozapine or olanzapine with D2 receptor was greatly affected by a mixture of HRP/H(2)O(2) known to induce the formation of nitrenium ion. Unlike diazepine derivatives, the oxidative mixture had low impact on the affinity of oxa- and thiazepine derivatives such as loxapine, clothiapine or JL13 for the D2 receptor. Molecular docking simulations revealed a huge difference between the mode of interaction of clozapine nitrenium ion and the parent drug. Electronic and geometric changes of the tricyclic ring system caused by the oxidation appeared to prevent the compound finding the correct binding mode and could therefore explain the difference observed in binding affinities.

Clozapine and N-Methyl- d-Aspartate have positive modulatory actions on their respective discriminative stimulus properties in C57BL/6 mice

The impairment of N-Methyl- d-Aspartate receptors is thought to contribute to negative symptoms and cognitive deficits. In vitro studies suggest that atypical antipsychotic drugs like clozapine may help to alleviate these deficits by enhancing glutamatergic function. The present study examined the in vivo interaction of clozapine with N-Methyl d-aspartate by training one group of C57BL/6 mice to discrimination 2.5 mg/kg clozapine from vehicle and another group to discriminate 30 mg/kg N-Methyl d-aspartate from vehicle in a two-lever drug discrimination task. Cross-generalization testing revealed that N-Methyl d-aspartate (3–56 mg/kg) failed to substitute for clozapine in the clozapine-trained mice, while clozapine (0.625 mg/kg) produced partial substitution in the N-Methyl d-aspartate-trained mice. Interestingly, administration of a low, non-generalizing dose of each training drug in combination with the full range of doses of the alternate training drug produced full and dose–dependent substitution in both clozapine- and N-Methyl d-aspartate-trained mice. The α 1 antagonist prazosin fully and dose-dependently substituted for both clozapine and N-Methyl d-aspartate. These results suggest that the shared discriminative stimulus properties between clozapine and N-Methyl d-aspartate may be mediated through indirect mechanisms, possibly in part through α 1 adrenergic antagonism.

Cardiovascular Disease Mortality in Patients With Chronic Schizophrenia Treated With Clozapine

Cardiovascular disease (CVD) mortality in schizophrenia is more frequent than in the general population. Whether second-generation antipsychotics (SGAs) increase risk of CVD morbidity and mortality has yet to be determined. We conducted a retrospective cohort study using an administrative database to identify patients with DSM-III- or DSM-IV-diagnosed schizophrenia, treated in Maryland, who started clozapine treatment (n = 1,084) or were never treated with clozapine (initiated on risperidone; n = 602) between 1994 and 2000. Deaths between 1994 and 2004 were identified by the Social Security Death Index, and death records were obtained. During the 6- to 10-year follow-up period, there were 136 deaths, of which 43 were attributed to CVD. Cardiovascular disease mortality in patients aged younger than 55 years at medication start was approximately 1.1% (clozapine, 1.1%; risperidone, 1.0%) in both groups at 5 years and 2.7% (clozapine) and 2.8% (risperidone) at 10 years (chi(2)(1) = 0.12, P = .73). Patients who started treatment at ages >or= 55 years had CVD mortality of 8.5% (clozapine) and 3.6% (risperidone) at 5 years and 16.0% (clozapine) and 5.7% (risperidone) at 10 years (chi(2)(1) = 2.13, P = .144). In a Cox regression model, patients aged >or= 55 years were at greater risk of mortality than younger patients (hazard ratio = 4.6, P < .001); whites were at greater risk than nonwhites (HR = 2.1, P = .046); however, SGA treatment (HR = 1.2; 95% CI, 0.6-2.4; P = .61) and sex (HR = 0.9, P = .69) were not statistically significant predictors of CVD, nor was there a significant age x clozapine interaction (chi(2)(1) = 1.52, P = .22). Age-, race-, and gender-adjusted standardized mortality ratios were significantly elevated (clozapine, 4.70; 95% CI, 3.19-6.67; risperidone, 2.88; 95% CI, 1.38-5.30) compared to year 2000 rates for the Maryland general population but did not differ by antipsychotic group (chi(2)(1) = 1.42, P = .23). The risk of CVD mortality in schizophrenia does not differ between clozapine and risperidone in adults despite known differences in risk profiles for weight gain and metabolic side effects. However, we cannot rule out an increased risk of CVD mortality among those starting treatment at ages 55 years or older.

Clozapine interaction

Clozapine interaction