Receptors Involved in Mental Disorders and the Use of Clozapine, Chlorpromazine, Olanzapine, and Aripiprazole to Treat Mental Disorders

Beyond the Phenothiazine Core: Mechanistic Insights into the Three-Electron Oxidation of Chlorpromazine

This study investigates the electrochemical oxidation mechanisms of chlorpromazine (CPZ), revealing a novel three-electron oxidation pathway that challenges the traditionally accepted two-electron paradigm, offering new insights into CPZ oxidation pathways. Using an integrated approach combining cyclic voltammetry, bulk electrolysis, UV-Vis, FT-IR, 1H-NMR spectroscopy, and LC-MS/MS analysis, we demonstrate that CPZ undergoes sequential oxidation processes involving both the phenothiazine core and the tertiary amine-containing side chain. Our results highlight the critical role of side-chain oxidation in forming nor-CPZ sulfoxide, an often-overlooked metabolite, which may influence CPZ's metabolic and pharmacological behaviour. Spectroelectrochemical data reveal stable intermediate species, providing insight into the structural rearrangements accompanying oxidation. This work offers a detailed mechanistic understanding of CPZ redox behaviour, contributing to improved interpretations of its pharmacological and metabolic properties.

Bupropion Increased More than Five Times the Systemic Exposure to Aripiprazole: An In Vivo Study in Wistar albino Rats

Background/Objectives: In psychiatric disorders, antipsychotics and antidepressant medication are often administered together. Aripiprazole, a third-generation antipsychotic drug, is extensively metabolized by CYP2D6 and CYP3A4 isoenzymes, while bupropion, used in depressive disorders, is known as a moderate or strong CYP2D6 enzyme inhibitor. This in vivo experiment aimed to assess the presence of a pharmacokinetic drug interaction between aripiprazole and bupropion and its magnitude on the systemic exposure of aripiprazole. Methods: 24 healthy Wistar albino male rats were included in two study groups. A single dose of 8 mg/kg aripiprazole was given to rats in the reference group, while the test group received repeated doses of bupropion for 6 days, followed by a single dose of aripiprazole. An LC-MS/MS method was developed for the concomitant quantification of aripiprazole and its active metabolite, dehydroaripiprazole, and non-compartmental analysis was employed to assess their pharmacokinetic parameters. Results: The mean AUC0-∞ of aripiprazole increased 5.65-fold (1117.34 ± 931.41 vs. 6311.66 ± 2978.71 hr·ng/mL), the mean Cmax increased by 96.76% and the apparent systemic clearance decreased over 9-fold after bupropion repeated doses. The exposure to aripiprazole's active metabolite increased as well, having a 4-fold increase in the mean AUC0-∞ (from 461.13 ± 339.82 to 1878.66 ± 1446.91 hr·ng/mL) and a 2-fold increase in the mean Cmax. Conclusions: The total exposure to the aripiprazole parent compound and active moiety significantly increased after bupropion pretreatment in this preclinical in vivo experiment. Clinical studies should further establish the significance of this interaction in humans.

Facile, eco-friendly and sensitive fluorimetric approach for detection of chlorpromazine: Application in biological fluids and tablet formulations as well as greenness evaluation of the analytical method

Monitoring antipsychotic drugs in biological fluids, such as human serum and urine, is important for ensuring the safety and efficacy of psychiatric treatments. This process helps maintain therapeutic drug levels, minimize side effects, and optimize patient well-being. Chlorpromazine (CZ) is a widely prescribed antipsychotic drug used for conditions like schizophrenia, bipolar disorder, and acute psychosis. Almost all existing sensing techniques for CZ are either insensitive spectrophotometric methods or involve long and complex chromatographic procedures, limiting their routine use. In this work, we introduce a facile, green, and sensitive fluorimetric strategy with high reproducibility for detecting CZ in its pure form, tablet formulation, and spiked human plasma and urine without the need for derivatization reactions. The proposed method relies on the inhibition of the intramolecular photoinduced electron transfer (PET) effect by using 2.0 M acetic acid. This approach enables the linear detection of CZ from 3.0 to 600 ng/mL with remarkably low quantitation and detection limits of 1.51 and 0.49 ng/mL, respectively. Moreover, the developed method's greenness was evaluated.

Association of HTR1A Gene Polymorphisms with Efficacy and Plasma Concentrations of Atypical Antipsychotics in the Treatment of Male Patients with Schizophrenia

PURPOSE

We investigate the association of HTR1A rs10042486 and rs6295 with efficacy and plasma concentrations of atypical antipsychotics in the treatment of male patients with schizophrenia.

PATIENTS AND METHODS

A total of 140 male patients diagnosed with schizophrenia who were treated with any single atypical antipsychotic between May 2020 and May 2022 were retrospectively included. Clinical symptoms were assessed using Positive and Negative Syndrome Scale (PANSS). All SNPs were typed using Agena Bioscience MassARRAY DNA mass spectrometry. Plasma concentrations of antipsychotics at week 3, 6 and 12 after treatment commence were analyzed using mass spectrometry.

RESULTS

For efficacy of atypical antipsychotics, we observed no significant difference between HTR1A rs10042486, rs6295 and positive symptom improvement, where the patients with heterozygous mutant at the rs10042486 and rs6295 locus were superior to those with wild-type or homozygous mutant genotypes on negative symptom improvement, especially at 12 weeks of follow-up when the difference between genotypes at the rs6295 locus have statistical significance (P = 0.037). For plasma concentration, we found that quetiapine plasma concentrations were significantly lower in patients with mutation-heterozygous types than in wild-type and homozygous mutation genotypes at week 6. In contrast, higher plasma concentrations were found for mutant heterozygous than wild genotypes in the risperidone monotherapy analysis, and the difference among genotypes at the rs6295 locus was statistically significant at 6 weeks of follow-up.

CONCLUSION

The assessment of the correlation of genetic polymorphisms of HTR1A rs6295 and rs10042486 in male patients with schizophrenia with the monitoring of therapeutic drug concentrations and therapeutic efficacy provides a constructive foundation for the clinical individualization of antipsychotics, such as quetiapine and risperidone, which is important in selecting the dose of the medication and improving the improvement of negative symptoms.

Quetiapine-Related Deaths: In Search of a Surrogate Endpoint

Quetiapine is a second-generation antipsychotic drug available for two and half decades. Due to increased misuse, prescription outside the approved indications, and availability on the black market, it is being encountered in medicolegal autopsies more frequently. For instance, it has been linked to increased mortality rates, most likely due to its adverse effects on the cardiovascular system. Its pharmacokinetic features and significant postmortem redistribution challenge traditional sampling in forensic toxicology. Therefore, a systematic literature review was performed, inclusive of PubMed, the Web of Science-core collection, and the Scopus databases; articles were screened for the terms "quetiapine", "death", and "autopsy" to reevaluate each matrix used as a surrogate endpoint in the forensic toxicology of quetiapine-related deaths. Ultimately, this review considers the results of five studies that were well presented (more than two matrices, data available for all analyses, for instance). The highest quetiapine concentrations were usually measured in the liver tissue. As interpreted by their authors, the results of the considered studies showed a strong correlation between some matrices, but, unfortunately, the studies presented models with poor goodness of fit. The distribution of quetiapine in distinct body compartments/tissues showed no statistically significant relationship with the length of the postmortem interval. Furthermore, this study did not confirm the anecdotal correlation of peripheral blood concentrations with skeletal muscle concentrations. Otherwise, there was no consistency regarding selecting an endpoint for analysis.

Effects of trazodone and dexmedetomidine on fentanyl-mediated reduction of isoflurane minimum alveolar concentration in cats

OBJECTIVE

To screen modulators of biogenic amine (BA) neurotransmission for the ability to cause fentanyl to decrease isoflurane minimum alveolar concentration (MAC) in cats, and to test whether fentanyl plus a combination of modulators decreases isoflurane MAC more than fentanyl alone.

STUDY DESIGN

Prospective, experimental study.

ANIMALS

A total of six adult male Domestic Short Hair cats.

METHODS

Each cat was anesthetized in three phases with a 1 week washout between studies. In phase 1, anesthesia was induced and maintained with isoflurane, and MAC was measured in duplicate using a tail clamp stimulus and standard bracketing technique. A 21 ng mL-1 fentanyl target-controlled infusion was then administered and MAC measured again. In phase 2, a single cat was administered a single BA modulator (buspirone, haloperidol, dexmedetomidine, pregabalin, ramelteon or trazodone) in a pilot drug screen, and isoflurane MAC was measured before and after fentanyl administration. In phase 3, isoflurane MAC was measured before and after fentanyl administration in cats co-administered trazodone and dexmedetomidine, the two BA modulator drugs associated with fentanyl MAC-sparing in the screen. Isoflurane MAC-sparing by fentanyl alone, trazodone-dexmedetomidine and trazodone-dexmedetomidine-fentanyl was evaluated using paired t tests with p < 0.05 denoting significant effects.

RESULTS

The MAC of isoflurane was 1.87% ± 0.09 and was not significantly affected by fentanyl administration (p = 0.09). In the BA screen, cats administered trazodone or dexmedetomidine exhibited 26% and 22% fentanyl MAC-sparing, respectively. Trazodone-dexmedetomidine co-administration decreased isoflurane MAC to 1.50% ± 0.14 (p < 0.001), and the addition of fentanyl further decreased MAC to 0.95% ± 0.16 (p < 0.001).

CONCLUSIONS AND CLINICAL RELEVANCE

Fentanyl alone does not affect isoflurane MAC in cats, but co-administration of trazodone and dexmedetomidine causes fentanyl to significantly decrease isoflurane requirement.

Long-Acting Injectable Antipsychotics-A Review on Formulation and In Vitro Dissolution

Long-acting injectable (LAI) neuroleptics constitute an effective therapeutical alternative for individuals suffering from persistent mental illness. These injectable pharmaceuticals help patients manage their condition better and improve long-term outcomes by preventing relapses and improving compliance. This review aims to analyse the current formulation aspects of LAI neuroleptics, with particular emphasis on analysis of drug release profiles as a critical test to guarantee drug quality and relevant therapeutical activity. While there is no officially approved procedure for depot parenteral drug formulations, various dissolution tests which were developed by LAI manufacturers are described. In vitro dissolution tests also possess a critical function in the estimation of the in vivo performance of a drug formulation. For that reason, thorough inspection of the in vitro-in vivo correlation (IVIVC) is also discussed.