Removal of imipramine using advanced oxidation processes: Degradation products and toxicity evolution.

Pharmaceuticals are frequently detected in natural and wastewater bodies, and are very important in environmental toxicology because of their stable nature. Advanced oxidation methods used to remove contaminants are of great benefit, especially removing pharmaceuticals unsuitable for biodegradation. In this study, imipramine was degraded by anodic oxidation and subcritical water oxidation, which are advanced oxidation methods. The determination of degradation products was performed by Q-TOF LC/MS analysis. The genotoxicity and cytotoxicity of the degradation samples were determined by the in vivo Allium Cepa method. Among the anodic oxidation samples, the lowest cytotoxicity was obtained after using 400 mA current, and 420 min of degradation time. No cytotoxic effect was observed in any subcritical water oxidation sample. However, when 10 mM hydrogen peroxide as an oxidant was used at 150 °C and the reaction time was 90 min, the subcritical water oxidation sample showed a genotoxic effect. The results of the study showed that it is crucial to evaluate the toxicity levels of the degradation products and which advanced oxidation methods are preferred for removing imipramine. The optimum conditions determined for both oxidation methods can be used as a preliminary step for biological oxidation methods in the degradation of imipramine.

Molecular Consequences of Depression Treatment: A Potential In Vitro Mechanism for Antidepressants-Induced Reprotoxic Side Effects.

The incidence of depression among humans is growing worldwide, and so is the use of antidepressants. However, our fundamental understanding regarding the mechanisms by which these drugs function and their off-target effects against human sexuality remains poorly defined. The present study aimed to determine their differential toxicity on mouse spermatogenic cells and provide mechanistic data of cell-specific response to antidepressant and neuroleptic drug treatment. To directly test reprotoxicity, the spermatogenic cells (GC-1 spg and GC-2 spd cells) were incubated for 48 and 96 h with amitriptyline (hydrochloride) (AMI), escitalopram (ESC), fluoxetine (hydrochloride) (FLU), imipramine (hydrochloride) (IMI), mirtazapine (MIR), olanzapine (OLZ), reboxetine (mesylate) (REB), and venlafaxine (hydrochloride) (VEN), and several cellular and biochemical features were assessed. Obtained results reveal that all investigated substances showed considerable reprotoxic potency leading to micronuclei formation, which, in turn, resulted in upregulation of telomeric binding factor (TRF1/TRF2) protein expression. The TRF-based response was strictly dependent on p53/p21 signaling and was followed by irreversible G2/M cell cycle arrest and finally initiation of apoptotic cell death. In conclusion, our findings suggest that antidepressants promote a telomere-focused DNA damage response in germ cell lines, which broadens the established view of antidepressants' and neuroleptic drugs' toxicity and points to the need for further research in this topic with the use of in vivo models and human samples.

Effects of serial cervical or tail blood sampling on toxicity and toxicokinetic evaluation in rats.

To assess the influences of blood sampling volumes or sites on toxicological and toxicokinetic (TK) evaluations, 4-week duration animal studies and a single-dose TK study of imipramine were conducted. In the toxicological evaluation, six-week-old Sprague-Dawley rats were divided into no blood and blood sampling groups. Fifty microliters (microsampling) or 100 µL (larger sampling) of blood/time point was collected from the jugular vein (50 µL of data was reported previously as Yokoyama et al., 2020) or the tail vein 6 to 7 times on days 1/2 and in week 4. Although no parameters were affected by the 100 µL sample from the tail vein, the 100 µL jugular vein sampling decreased the red blood cell parameters in females, possibly due to hemorrhage at the sampling site. Regarding the TK assessment, 50 µL of blood/site/time point was collected at 6 time points from the tail and jugular vein of the same male rats after single oral administration of 10 or 100 mg/kg imipramine, which was selected as a representative drug with high distribution volume. Although there were no differences in the AUC0-24hr and Cmax values between the sites, the plasma concentrations at the early time points were significantly lower from the tail vein than the jugular vein. From our studies, 50 µL of jugular and tail vein microsampling did not affect the toxicity parameters or AUC/Cmax. However, appropriate toxicity considerations and/or selection of the blood sampling site may be important in the case of larger sampling volumes or blood concentration assessment.

NS398, a cyclooxygenase-2 inhibitor, reverses memory performance disrupted by imipramine in C57Bl/6J mice.

Imipramine has been widely used as an antidepressant in the clinic over the years. Unfortunately, it produces a detrimental effect on memory. At the same time, COX-2 inhibitors engagement in the mechanisms of memory formation, and synapse plastic changes has been well documented. Our previous studies have demonstrated the contribution of cyclooxygenase-2 (COX-2) inhibition to the parameters of the mGluR5 pathway in memory formation. Because chronic administration of imipramine has been shown to affect mGluR5, the purpose of this study was to verify the hypothesis of COX-2 pathway engagement in disrupting effects of imipramine. Imipramine is currently used as a reference compound, and therefore it seems important to decipher and understand mood-related pathways, as well as cognitive changes activated during its use. This study covers the examination of spatial, and motor parameters. To this end, C57Bl/6J mice received imipramine, and NS398 (a COX-2 inhibitor) alone, or in combination for 7 or 14 days. We performed the modified Barnes maze (MBM), modified rotarod (MR) tests, and electrophysiological studies. The harmful effect of imipramine on MBM learning was improved by NS398 use. The same modulatory role of the COX-2 inhibitor in procedural learning in the MR test was found. In conclusion, our data show the involvement of the COX-2 pathway in changes in the long-term memory, and procedural memory of C57Bl/6J mice after chronic imipramine treatment.

Neuronal life or death linked to depression treatment: the interplay between drugs and their stress-related outcomes relate to single or combined drug therapies.

Depression is a serious medical condition, typically treated by antidepressants. Conventional monotherapy can be effective only in 60-80% of patients, thus modern psychiatry deals with the challenge of new methods development. At the same moment, interactions between antidepressants and the occurrence of potential side effects raise serious concerns, which are even more exacerbated by the lack of relevant data on exact molecular mechanisms. Therefore, the aims of the study were to provide up-to-date information on the relative mechanisms of action of single antidepressants and their combinations. In this study, we evaluated the effect of single and combined antidepressants administration on mouse hippocampal neurons after 48 and 96 h in terms of cellular and biochemical features in vitro. We show for the first time that co-treatment with amitriptyline/imipramine + fluoxetine initiates in cells adaptation mechanisms which allow cells to adjust to stress and finally exerts less toxic events than in cells treated with single antidepressants. Antidepressants treatment induces in neuronal cells oxidative and nitrosative stress, which leads to micronuclei and double-strand DNA brakes formation. At this point, two different mechanistic events are initiated in cells treated with single and combined antidepressants. Single antidepressants (amitriptyline, imipramine or fluoxetine) activate cell cycle arrest resulting in proliferation inhibition. On the other hand, treatment with combined antidepressants (amitriptyline/imipramine + fluoxetine) initiates p16-dependent cell cycle arrest, overexpression of telomere maintenance proteins and finally restoration of proliferation. In conclusion, our findings may pave the way to better understanding of the stress-related effects on neurons associated with mono- and combined therapy with antidepressants.

Degradation of imipramine by vacuum ultraviolet (VUV) system: Influencing parameters, mechanisms, and variation of acute toxicity.

Degradation of imipramine (IMI) in the VUV system (VUV185 + UV254) was firstly evaluated in this study. Both HO• oxidation and UV254 direct photolysis accounted for IMI degradation. The quantum yields of UV254 direct photolysis of deprotonated and protonated IMI were 1.31×10-2 and 3.31×10-3, respectively, resulting in the higher degradation efficiency of IMI at basic condition. Increasing the initial IMI concentration lowered the degradation efficiency of IMI. While elevating reaction temperature significantly improved IMI degradation efficiency through the promotion of both the quantum yields of HO• and the UV254 direct photolysis rate. The apparent activation energy was calculated to be about 26.6 kJ mol-1. Negative-linear relationships between the kobs of IMI degradation and the concentrations of HCO3-/CO32-, NOM and Cl- were obtained. The degradation pathways were proposed that cleavage of side chain and hydroxylation of iminodibenzyl and methyl groups were considered as the initial steps for IMI degradation in the VUV system. Although some high toxic intermediate products would be produced, they can be further transformed to other lower toxic products. The good degradation efficiency of IMI under realistic water matrices further suggests that the VUV system would be a good method to degrade IMI in aquatic environment.

Short-term exposure to tricyclic antidepressants delays righting time in marine and freshwater snails with evidence for low-dose stimulation of righting speed by imipramine.

Active pharmaceutical ingredients such as tricyclic antidepressants (TCAs) are contaminants of emerging concern which are commonly detected in wastewater effluent and which can disrupt the behavior of non-target organisms. In aquatic snails, the righting response is a critical behavior that has been shown to be inhibited by exposure to SSRI-type antidepressants. We exposed marine and freshwater snails to three tricyclic antidepressants (clomipramine, amitriptyline, and imipramine) for 1 h and measured righting response time. In the marine mud snail (Ilyanassa obsoleta), all three TCAs significantly increased righting time at concentrations as low as 156 µg/L. Similarly, in the freshwater snail Leptoxis carinata, all three TCAs increased righting time at concentrations as low as 263 µg/L. However, exposure to imipramine from 15.8 to 316 µg/L resulted in significantly faster righting time. Such low-dose stimulation and high-dose inhibition are characteristics of a hormetic response. We discuss the possible physiological mechanism of action of TCAs and other antidepressants on snail behavior, and the occurrence of non-monotonic, hormetic dose responses to human pharmaceuticals in the aquatic environment.

Mechanism-based risk assessment strategy for drug-induced cholestasis using the transcriptional benchmark dose derived by toxicogenomics.

Cholestasis is one of the major causes of drug-induced liver injury (DILI), which can result in withdrawal of approved drugs from the market. Early identification of cholestatic drugs is difficult due to the complex mechanisms involved. In order to develop a strategy for mechanism-based risk assessment of cholestatic drugs, we analyzed gene expression data obtained from the livers of rats that had been orally administered with 12 known cholestatic compounds repeatedly for 28 days at three dose levels. Qualitative analyses were performed using two statistical approaches (hierarchical clustering and principle component analysis), in addition to pathway analysis. The transcriptional benchmark dose (tBMD) and tBMD 95% lower limit (tBMDL) were used for quantitative analyses, which revealed three compound sub-groups that produced different types of differential gene expression; these groups of genes were mainly involved in inflammation, cholesterol biosynthesis, and oxidative stress. Furthermore, the tBMDL values for each test compound were in good agreement with the relevant no observed adverse effect level. These results indicate that our novel strategy for drug safety evaluation using mechanism-based classification and tBMDL would facilitate the application of toxicogenomics for risk assessment of cholestatic DILI.

High-throughput virtual screening and quantum mechanics approach to develop imipramine analogues as leads against trypanothione reductase of leishmania.

Visceral leishmaniasis (VL) has been considered as one of the most fatal form of leishmaniasis which affects 70 countries worldwide. Increased drug resistance in Indian subcontinent urged the need of new antileishmanial compounds with high efficacy and negligible toxicity. Imipramine compounds have shown impressive antileishmanial activity. To find out most potent analogue from imipramine series and explore the inhibitory activity of imipramine, we docked imipramine analogues (n=93,328) against trypanothione reductase in three sequential modes. Furthermore, 98 ligands having better docking score than reference ligand were subjected to ADME and toxicity, binding energy calculation and docking validation. Finally, Molecular dynamic and single point energy was estimated for best two ligands. This study uncovers the inhibitory activity of imipramine against Leishmania parasites.

[There's not only Alzheimer's disease]. / Es gibt nicht nur die Alzheimer-Demenz.

We report the case of a 59 year old man with a rapidly progressive cognitive decline, neurologic symptoms and recurrent falls. One of the most important differential diagnoses was the lithiumintoxication with normal lithium blood levels. After reducing the lithiumdosis the neurological symptoms regressed completely, and only few cognitive impairments persisted.

A novel class of potential prion drugs: preliminary in vitro and in vivo data for multilayer coated gold nanoparticles.

Gold nanoparticles coated with oppositely charged polyelectrolytes, such as polyallylamine hydrochloride and polystyrenesulfonate, were examined for potential inhibition of prion protein aggregation and prion (PrPSc) conversion and replication. Different coatings, finishing with a positive or negative layer, were tested, and different numbers of layers were investigated for their ability to interact and reduce the accumulation of PrPSc in scrapie prion infected ScGT1 and ScN2a cells. The particles efficiently hampered the accumulation of PrPSc in ScN2a cells and showed curing effects on ScGT1 cells with a nanoparticle concentration in the picomolar range. Finally, incubation periods of prion-infected mice treated with nanomolar concentrations of gold nanoparticles were significantly longer compared to untreated controls.

In vitro studies of DNA damage caused by tricyclic antidepressants: a role of peroxidase in the side effects of the drugs.

Studies show that tricyclic antidepressants prescribed for migraines, anxiety, and child enuresis have numerous adverse effects in living cells. One of the undesired outcomes observed under treatment with these drugs is DNA damage. However, the mechanisms underlying damage have yet to be elucidated. We performed in vitro studies of the DNA damage caused by four tricyclic antidepressants: imipramine, amitriptyline, opipramol, and protriptyline. We focused particularly on the DNA damage aided by peroxidases. As a model of a peroxidase, we used horseradish peroxidase (HRP). At pH 7, reactions of HRP with excess hydrogen peroxide and imipramine yielded an intense purple color and a broad absorption spectrum with the maximum intensity at 522 nm. Reactions performed between DNA and imipramine in the presence of H(2)O(2) and HRP resulted in the disappearance of the DNA band. In the case of the other three drugs, this effect was not observed. Extraction of the DNA from the reaction mixture indicated that DNA is degraded in the reaction between imipramine and H(2)O(2) catalyzed by HRP. The final product of imipramine oxidation was identified as iminodibenzyl. We hypothesize that the damage to DNA was caused by an imipramine reactive intermediate.

In vivo canine model comparison of cardiovascular effects of antidepressants milnacipran and imipramine.

Milnacipran is a specific serotonin and norepinephrine reuptake inhibitor, which has been widely used against major depressive episodes. In this study, cardiovascular effects of milnacipran were assessed in comparison with those of a typical tricyclic antidepressant imipramine using the halothane-anesthetized dogs. Milnacipran (n = 6) or imipramine (n = 6) was intravenously administrated in three escalating doses of 0.1, 1 and 10 mg/kg over 10 min with a pause of 20 min between the doses. Clinically relevant plasma concentrations were obtained after 0.1-1 mg/kg of milnacipran in this study, whereas therapeutic dose and plasma concentration of imipramine were reported to be similar to those of milnacipran. The low and middle doses of milnacipran hardly affected cardiohemodynamic or electrophysiological variables except that they slightly increased vascular tone and ventricular contraction, whereas same doses of imipramine delayed repolarization process without affecting the other variables. The high dose of both milnacipran and imipramine induced similar extent of negative chronotropic, inotropic and dromotropic effects together with vasoconstriction and repolarization delay. Thus, the effects of milnacipran may be more selective for cardiohemodynamics than for repolarization delay, whereas reverse will be true for imipramine, supporting lack of clinical report of patients with milnacipran-induced long QT syndrome unlike imipramine.

Chromosomal aberrations induced by imipramine and desipramine in mouse.

Imipramine (IMI) and desipramine (DES) are two drugs widely used for the treatment of depression as well as for other diseases. In the present study, we determined their capacity to induce chromosomal aberrations in mouse bone marrow cells. Three doses of each compound were tested and their results were compared with the frequency of chromosomal aberrations obtained in a control group as well as with a group treated with cyclophosphamide. Our results showed a significant increase in chromosome damage with the doses tested for each compound: 7, 20, and 60 mg/kg in the case of IMI, and 2, 20, and 60 mg/kg as regards DES. This last drug induced stronger chromosomal damage than IMI. Our results agree with previous studies regarding the induction of micronuclei and sister chromatid exchanges by the drugs in mouse and suggest caution with respect to their use in long-term treatments.

Micronuclei induced by imipramine and desipramine in mice: a subchronic study.

Depression is a common disease that may cause severe damage to human health. Imipramine (IMI) and desipramine (DES) are medicaments used for treatment, yet studies on their genotoxic potential have given controversial results. Therefore, we designed the present assay to determine their effect as inducers of micronucleated polychromatic erythrocytes (MNPE) and micronucleated normochromatic erythrocytes (MNNE) in mice. The study was carried out in animals administered daily with the compounds for 4 weeks, and the determination of micronuclei was done each week. We also evaluated the bone marrow cytotoxicity induced by the chemicals. Besides, the same determinations were carried out in the following 4 consecutive weeks, but in this period the animals were not treated with the tested compounds. Our results showed a significant increase in both MNPE and MNNE induced by both compounds from the first week of administration. At the fourth week, IMI increased three times the control level, while the effect of DES was about seven times such level. In the second, 4-week phase, we observed a reduction in the rate of micronuclei approaching the control level. We also detected a bone marrow-mitotic division decrease by the evaluated chemicals. Our results point to the need for cautiousness in the clinical use of the compounds as well as for testing the effect in patients under treatment.

In vitro biotransformation of amitriptyline and imipramine with rat hepatic S9 fraction: evaluation of the toxicity with Spirotox and Thamnotoxkit F Tests.

Pharmaceutical products, as well as their related metabolites, end up in the aquatic environment after use. Little is known about the effects and the hazard of exposure to drugs for aquatic organisms. This study was designed to assess the ecotoxicity of amitriptyline (AMI), imipramine (IMI), and their metabolites. The tested drugs were very toxic to the protozoan Spirostomum ambiguum and the crustacean Thamnocephalus platyurus with the LC50 values around 1 mg l(-1). Moreover, simple additivity occurs between the drugs and their N-desmethyl metabolites. Tested compounds were incubated with S9 rat hepatocyte fraction at 37 degrees C for 4 hours. Unchanged drugs and metabolites were determined using high-pressure liquid chromatography-photodiode array detector. AMI and IMI were biotransformed almost completely. Three AMI and IMI metabolites were detected: desmethyl-, didesmethyl-, and N-oxide. The toxicity of the deproteinated reaction mixtures (TU) was compared to the toxicity equivalency units (TEU) calculated based on the concentrations of the drugs and their LC50 values. It has been demonstrated that the toxicity of mixture of metabolites to Spirotox and Thamnotoxkit F is higher than the predicted value calculated from the concentrations of the drugs and their N-desmethylated derivatives in the sample. The results indicate that the harmfulness of the drug metabolites should be taken into consideration in the ecotoxicological studies.

Differential neurotoxicity of tricyclic antidepressants and novel derivatives in vitro in a dorsal root ganglion cell culture model.

BACKGROUND AND OBJECTIVE: Tricyclic antidepressants are commonly employed orally to treat major depressive disorders and have been shown to be of substantial benefit in various chronic pain conditions. Among other properties they are potent Na+ channel blockers in vitro and show local anaesthetic properties in vivo. The present study aimed to determine their differential neurotoxicity, and that of novel derivatives as prerequisite for their potential use in regional anaesthesia. METHODS: To directly test neurotoxicity in adult peripheral neurons, the culture model of dissociated adult rat primary sensory neurons was employed. Neurons were incubated for 24 h with amitriptyline, N-methyl-amitriptyline, doxepin, N-methyl-doxepin, N-propyl-doxepin, desipramine, imipramine and trimipramine at 100 mumol, and at concentrations correlating to their respective potency in blocking sodium channels. RESULTS: All investigated substances showed considerable neurotoxic potency as represented in significantly decreased neuron numbers in cultures as compared to controls. Specifically, doxepin was more neurotoxic than amitriptyline, and both imipramine and trimipramine were more toxic than desipramine or amitriptyline. Novel derivatives of tricyclic antidepressants were, in general, more toxic than the parent compound. CONCLUSIONS: Tricyclic antidepressants and novel derivatives thereof show differential neurotoxic potential in vitro. The rank order of toxicity relative to sodium channel blocking potency was desipramine < amitriptyline < N-methyl amitriptyline < doxepin < trimipramine < imipramine < N-methyl doxepin < N-propyl doxepin.

Mechanism of imipramine-induced seizures in amygdala-kindled rats.

The present study was undertaken to get insight in the possible mechanisms of imipramine-induced seizures in amygdala-kindled rats. The intraperitoneal (i.p.) injection of imipramine produced potent behavioral and electroencephalogram (EEG) seizures in amygdala-kindled rats. Histidine (1500 mg/kg, i.p.) and histamine (10 and 20 microg, i.c.v.) significantly attenuated the seizures induced by imipramine (50 mg/kg, i.p.) in kindled rats. In addition, the inhibition of imipramine-induced seizures by histamine (20 microg, i.c.v.) was antagonized by an H1 antagonist, pyrilamine. An H3 antagonist, thioperamide (50 microg, i.c.v.), also significantly attenuated the imipramine-induced seizures in kindled rats. The i.p. injection of alpha-methyl-p-tyrosine at a dose of 250 mg/kg significantly diminished the seizures induced by imipramine. However, p-chlorophenylalanine and physostigmine did not affect the imipramine-induced seizures to any extent. These data give strong hints that the H1 receptor antagonistic properties and the brain noradrenaline activating effects of imipramine are centrally involved in imipramine-induced seizures, and central serotonergic and cholinergic neurotransmissions are not involved in the seizures induced by imipramine in amygdala-kindled rats.

Exacerbation of harmaline-induced tremor by imipramine.

Imipramine is a well-established tricyclic antidepressant which was first approved for the treatment of depression in the late fifties. Antidepressant effect of imipramine is attributed to inhibition of serotonin (5HT) and noradrenaline (NA) reuptake in brain. These monoamines have been implicated in a variety of neurological disorders including tremor. In the present investigation attempt was made to study the effect of imipramine on harmaline-induced tremor in rats. Male Sprague Dawley rats weighing 115+/-2.5 g were given harmaline (10 mg/kg, i.p.) alone or along with imipramine (30 min before harmaline) in doses of 60 and 90 mg/kg respectively. The latency of onset, intensity and duration of tremor and EMG were recorded. To substantiate the role of 5HT in aetiopathology of tremor the above experiment was repeated in the rats pretreated with P-chlorophenylalanine (PCPA), a potent 5HT depleter. The levels of 5HT and 5-hydroxyindole acetic acid (5HIAA) in the brain stem were measured using high performance liquid chromatography. Imipramine dose-dependently exacerbated the duration, intensity and amplitude of EMG following harmaline-induced tremor. Imipramine treatment further decreased harmaline-induced 5HT turnover in the brain stem. However, this was statistically insignificant. Depletion of 5HT produced a significant reduction in the intensity and duration of harmaline-induced tremor. In conclusion, this study suggests that imipramine exacerbates harmaline-induced tremor. Clinical use of imipramine for the treatment of depression in patients who also suffer from tremors may require a close monitoring.

Animal models of heart failure: what is new?

Heart failure is the major cause of mortality in Western countries. Medical treatment of heart failure is associated with 50% survival at 5 years. Experimental models are required to better understand the progression of the disease and elaborate new therapy. Heart transplantation, left ventricular assist devices, artificial hearts, and cardiac bioassist techniques require animal models for testing and optimizing before they are implemented on human patients. The perfect model of heart failure that reproduces every aspect of the natural disease does not exist. Acute and chronic heart failure models have been developed to reproduce different aspect of the pathology.