Synthesis of the major metabolites of paroxetine

Various species of Basidiomycota fungi reveal different abilities to degrade pharmaceuticals and also different pathways of degradation

The presence of pharmaceuticals (PhACs) in the aquatic environment is an emerging problem worldwide. PhACs reach surface water via the effluents of wastewater treatment plants (WWTPs). WWTPs, although able to remove organic pollutants, do not always remove PhACs. Currently, in the treatment of sewage with the activated sludge method, numerous microorganisms are used, mostly bacteria. Nevertheless, these microorganisms are not resistant to many drug contaminants, and some may also pose a risk to human health. White-rot fungi (WRF), which degrade a wide spectrum of environmental pollutants, may be used as an alternative to microorganisms. However, little data exists comparing the removal of various PhACs by different WRF. In this study, we aimed to determine the ability of three WRF Basidiomycota species, Armillaria mellea, Phanerochaete chrysosporium, and Pleurotus ostreatus, to remove PhACs from various therapeutic groups over the course of 1 h-4 days. Additionally, we identified the fungal metabolites of PhACs, proposed the degradation pathways, and assessed the toxicity of the post-culture media. All selected WRF removed PhACs, but the degree of removal depended on WRF species and PhACs type. Antidepressants and immunosuppressants were removed most efficiently by P. ostreatus, cardiovascular drugs and sulfamethoxazole by A. mellea, and erythromycin by P. chrysosporium. The vast differences observed highlight the need for more intensive testing of different WRF species to select the best species for removing pharmaceuticals of interest. The structure of metabolites generated during degradation strongly depended on WRF species, but the most frequent xenobiotic transformations were oxidation and dealkylation. The obtained results gave insight into the substrate specificity of selected WRF while also providing a broad extension of the knowledge of pharmaceutical degradation by A. mellea.

Chirality of antidepressive drugs: an overview of stereoselectivity

Stereochemistry plays an important role in drug design because the enantiomers of a drug frequently vary in their biological action and pharmacokinetic profiles. Racemates of a drug with either an inactive or an unsafe enantiomer can lead to detrimental effects. The manufacturing industry may still produce racemates, but such decisions must pass through rigorous analyses of the pharmacological and pharmacokinetic characteristics of the particular enantiomer related to the racemates. The pharmacokinetics of antidepressants or antidepressive agents is stereoselective and predominantly favors one enantiomer. The use of pure enantiomers offers (i) better specificity than the racemates in terms of certain pharmacological actions, (ii) enhanced clinical indications, and (iii) optimized pharmacokinetics. Therefore, controlling the stereoselectivity in the pharmacokinetics of antidepressive drugs is of critical importance in dealing with depression and psychiatric conditions. The objective of this review is to highlight the importance of the stereochemistry of antidepressants in the context of the design and development of new chirally pure pharmaceuticals, the potential complications caused by using racemates, and the benefits of using pure enantiomers.

Variants in COMT, CYP3A5, CYP2B6, and ABCG2 Alter Quetiapine Pharmacokinetics

Quetiapine is an atypical antipsychotic widely used for the treatment of schizophrenia and the depressive episodes of bipolar disorder. The aim of this work was to investigate the effect of variants in relevant pharmacogenes in the pharmacokinetics of quetiapine and to exploratorily evaluate adverse drug reaction (ADR) incidence based on genetic polymorphism. Specifically, 49 healthy volunteers enrolled in two bioequivalence clinical trials were included in this study. In addition, 80 variants in 19 relevant pharmacogenes were genotyped, including cytochrome P450 (CYP) genes, catechol-O-methyl transferase (COMT), other enzymes (e.g., UGT1A1 or UGT1A4), and transporters (e.g., SLCO1B1, ABCB1, or ABCG2). The COMT rs13306278 T allele was significantly related to quetiapine-increased exposure. We demonstrated the existence of quetiapine derivatives with a catechol-like structure (7,8-dihydroxi-quetiapine and 7,8-dihydroxi-N-desalkyl-quetiapine), which would be COMT metabolites and would explain quetiapine accumulation through CYP2D6 and CYP3A4 negative feedback. Moreover, CYP3A5 and CYP2B6 phenotypes were related to quetiapine exposure variability, which confirms (for CYP3A5) and suggests (for CYP2B6) that these enzymes play an important role in quetiapine’s metabolism. Finally, the ABCG2 rs2231142 T allele was related to quetiapine accumulation. Further studies are required to confirm the clinical relevance of our findings.

Application of Pleurotus ostreatus to efficient removal of selected antidepressants and immunosuppressant

Disposed pharmaceuticals constitute a significant threat to the environment due to the high consumption of drugs and inefficient treatment of wastewater. In this paper, we first described the efficient removal of a series of antidepressants and immunosuppressant from a cultivation medium carried out by white-rot fungus, Pleurotus ostreatus. We determined the removal efficiency of pharmaceuticals and the activity of fungal ligninolytic enzymes over time, as well as the toxicity of pre- and post-cultivation medium to Spirostomum ambiguum. We showed that P. ostreatus can remove from the model medium most of the pharmaceuticals studied, including clomipramine, mianserin, paroxetine, sertraline, and mycophenolic acid. Pharmaceuticals containing phenolic or benzene moieties, likewise in the natural monolignols, were removed in a high efficiency within a short time. The activity of the fungal ligninolytic enzymes, laccase, and lignin peroxidase, in the cultivation medium, was three times higher in the presence of the pharmaceuticals, which justifies their contribution to the degradation. The post-cultivation medium showed lower toxicity than pre-cultivation medium and toxic units were 7- and 2-fold lower for the sublethal and lethal response, respectively. Over twenty metabolites we detected resulted mostly from oxygenation or demethylation of parent pharmaceuticals. The biological treatment we developed using P. ostreatus-based system should be convenient and effective in mycoremediation of environmental wastewater polluted with emerging contaminants including monolignol-like antidepressants and immunosuppressant.

Hybrid molecules inhibiting myeloperoxidase activity and serotonin reuptake: a possible new approach of major depressive disorders with inflammatory syndrome

Objectives

Major depressive disorder (MDD) is accompanied with an imbalance in the immune system and cardiovascular impairments, such as atherosclerosis. Several mechanisms have been pointed out to underlie this rather unexpected association, and among them the activity of myeloperoxidase (MPO). The aim of our study was to find compounds that inhibit both MPO and serotonin transporter (SERT) for treating MDD associated with cardiovascular diseases.

Methods

SERT inhibition was assessed with measuring of [3H]-serotonin uptake using HEK-293 MSR cells. MPO inhibition was determined by taurine chloramine test on 3-(aminoalkyl)-5-fluoroindole derivatives and on clinically relevant antidepressants. All kinetic measurements were performed using a temperature-controlled stopped-flow apparatus (model SX-18 MV). Promising lead compounds were docked onto SERT 3D structure modelled using the LeuT structure complexed to tryptophan (PDB code 3F3A). Their toxicological profile was also assessed.

Key findings

3-(aminoalkyl)-5-fluoroindole derivative with 5 carbons on the side chain and paroxetine showed the best activity on both MPO and SERT at the nanomolar range. Paroxetine was found to be the first irreversible MPO inhibitor at nanomolar concentrations.

Conclusions

Our results put forward the first hybrid molecule (compound 25) and drug (paroxetine) that can be especially used in MDD associated with inflammatory syndrome.

New validated HPLC methodology for the determination of (-)-trans-paroxetine and its enantiomer in pharmaceutical formulations with use of ovomucoid chiral stationary phase

A new chromatographic method for the enantioseparation and the determination of (−)-trans-paroxetine and (+)-trans-paroxetine has been developed with the aid of amylose ovomucoid-based chiral stationary phase. The method is faster and five times more sensitive than procedures recommended previously: limit of detection and limit of quantification are 5 and 16 ng/mL, respectively [modified (Ferretti et al. in J Chromatogr B 710:157–164, 1998): 20 and 60 ng/mL]. It was carefully validated and applied for the determination of (−)-trans-paroxetine and (+)-trans-paroxetine in Parogen (Mc Dermott Laboratories Ltd.) and Xetanor (Actavis) coated tablets.

Figure

[(3R,4S)-4-(4-Fluorophenyl)-1-methylpiperidin-3-yl]methyl 4-methylbenzenesulfonate

In the title compound, C₂₀H₂₄FNO₃S, the piperidine ring adopts a chair conformation. The dihedral angle between the aromatic rings is 47.01 (17)°.

An electrospray ionisation tandem mass spectrometric investigation of selected psychoactive pharmaceuticals and its application in drug and metabolite profiling by liquid chromatography/electrospray ionisation tandem mass spectrometry

A tandem mass spectrometric investigation of the collision-induced dissociation of five commonly prescribed psychoactive pharmaceuticals, risperidone, sertraline, paroxetine, trimipramine, and mirtazapine, and their metabolites has been carried out. Quadrupole ion trap mass spectrometry was employed to generate tandem mass spectrometric (MS/MS) data of the compounds under investigation and structural assignments of product ions were supported by quadrupole time-of-flight mass spectrometry. These fragmentation studies were then utilised in the development of a liquid chromatographic method to identify the drugs and their metabolites in human hair and saliva samples, thus providing relevant profiling information.