Paliperidone regulates intracellular redox system in rat brain: Role of purine mechanism

A novel mucoadhesive paliperidone-nanoemulsion developed using the ultrasonication method in the treatment of schizophrenia

Aim: To develop paliperidone mucoadhesive-nanoemulsion (PLP-NE) to enhance brain bioavailability. To evaluate comparative effects of PLP-NE and CS-PLP-NE in the treatment of schizophrenia, followed by a toxicity study of opt-NE. Material and methods: Oil: oleic acid, surfactant: Tween-80, and co-surfactant: Labrasol were chosen based on the solubility and maximum nanoemulsion area. The ultrasonication technique was applied with the aqueous micro titration method for the development of PLP-NE. The optimization of the method for the excellent PLP-NE was performed using a central composite design based on a five-factor and four-level. Oil (% v/v), S mix (v/v%), ultrasonication intensity in percentage, ultrasonication time in minutes, and temperature (°C) were optimized and used to the independent variables. Results: The parameters i.e., oil (5%), S mix (10%), ultrasonication time (5.0 min), ultrasonication intensity (25%), and temperature (38 °C) were optimized and used as independent and dependent variables for the development of novel PLP-NE. Based on experimental data, the dependent variables, i.e., globule size (53.90 ± 4.01 nm), % transmittance (92.56% ± 1.06%), PDI (0.218 ± 0.007), and zeta potential (-11.60 ± 0.031 mV), were determined. The smooth near about spherical shaped of PLP-NE globules with, refractive index i.e., 1.62 ± 0.021, viscosity: 39 ± 6 cp with the pH: 7.40 ± 0.089, and content of drug (97.98 ± 0.39%) for optimized-PLP-NE. The optimized PLP-NE with oleic acid, Tween-80, and Labrasol was used to improve brain bioavailability with good permeation via the intranasal route. CS-PLP-NE yielded good mucoadhesive property results compared to paliperidone-nanoemulsion, and PLP-S containing a 0.751 minutes retention time with their deuterated-IS (0.806 min) and m/z of 427.2/207.2 with IS (m/z: 431.2/211.2) for PLP and PLP-IS. A calibration curve was plotted with a linear range of 1-2000 ng mL-1 with inter- and intraday accuracy (97.03-99.31%) and precision (1.69-50.05%). The results of AUC(0-24) and C max for PLP were found to be highly significant (p < 0.001) as an improvement of brain bioavailability in rats via intranasal delivery of CS-PLP-NE. Furthermore, the locomotion test, social interaction, and forced swimming test (forced swimming, climbing, and immobility) of a mucoadhesive CS-PLP-NE (intranasally) provided highly significant results with the improvement of behavioral analysis when compared to the PLP-NE and PLP-S studies. Conclusion: CS-PLP-NE (i.n.) showed highly significant results, i.e., p < 0.001 for the improvement of bioavailability of the brain in the treatment of schizophrenia. Optimized-mucoadhesive-CS-based-PLP-NE is safe and shows no toxicity.

Schizophrenia, Curcumin and Minimizing Side Effects of Antipsychotic Drugs: Possible Mechanisms

Schizophrenia is a mental disorder characterized by episodes of psychosis; major symptoms include hallucinations, delusions, and disorganized thinking. More recent theories focus on particular disorders of interneurons, dysfunctions in the immune system, abnormalities in the formation of myelin, and augmented oxidative stress that lead to alterations in brain structure. Decreased dopaminergic activity and increased phospholipid metabolism in the prefrontal cortex might be involved in schizophrenia. Antipsychotic drugs used to treat schizophrenia have many side effects. Alternative therapy such as curcumin (CUR) can reduce the severity of symptoms without significant side effects. CUR has important therapeutic properties such as antioxidant, anti-mutagenic, anti-inflammatory, and antimicrobial functions and protection of the nervous system. Also, the ability of CUR to pass the blood-brain barrier raises new hopes for neuroprotection. CUR can improve and prevent further probable neurological and behavioral disorders in patients with schizophrenia. It decreases the side effects of neuroleptics and retains lipid homeostasis. CUR increases the level of brain-derived neurotrophic factor and improves hyperkinetic movement disorders. CUR may act as an added counteraction mechanism to retain cell integrity and defense against free radical injury. Thus it appears to have therapeutic potential for improvement of schizophrenia. In this study, we review several properties of CUR and its ability to improve schizophrenia and minimize the side effects of antipsychotic drugs, and we explore the underlying mechanisms by which CUR affects schizophrenia and its symptoms.

Decreased Activity of Erythrocyte Catalase and Glutathione Peroxidase in Patients with Schizophrenia

Background and Objectives: Catalase and glutathione peroxidase (GPx) are important antioxidant enzymes that break down hydrogen peroxide (H2O2) in order to control its intracellular concentration, thus enabling its physiological role and preventing toxic effects. A lack or disruption of their function leads to the accumulation of hydrogen peroxide and the occurrence of oxidative stress. Accumulating studies have shown that the activities of key antioxidant enzymes are impaired in patients with schizophrenia. Since the published results are contradictory, and our previous studies found significantly higher erythrocyte superoxide dismutase (SOD) activity in patients with schizophrenia, the aim of this study was to determine the activity of enzymes that degrade hydrogen peroxide in the same group of patients, as well as to examine their dependence on clinical symptoms, therapy, and parameters associated with this disease. Materials and Methods: Catalase and GPx activities were determined in the erythrocytes of 68 inpatients with schizophrenia and 59 age- and gender-matched healthy controls. The clinical assessment of patients was performed by using the Positive and Negative Syndrome Scale (PANSS). The catalase activity was measured by the kinetic spectrophotometric method, while the GPx activity was determined by the commercially available Ransel test. Results: Erythrocyte catalase and GPx activities were significantly lower (p < 0.001 and p < 0.01, respectively) in subjects with schizophrenia than they were in healthy individuals. Lower catalase activity does not depend on heredity, disease onset, the number of episodes, or disease duration, while GPx activity showed significant changes in patients who had more than one episode and in those who had been suffering from the disease for over a year. Significantly lower catalase activity was noted in the PANSS(+/−) group in comparison with the PANSS(+) and PANSS(−) groups. The lowest catalase activity was found in subjects who were simultaneously treated with first- and second-generation antipsychotics; this was significantly lower than it was in those who received only one class of antipsychotics. Conclusion: These results indicate the presence of oxidative stress in the first years of clinically manifested schizophrenia and its dependence on the number of psychotic episodes, illness duration, predominant symptomatology, and antipsychotic medication.

Unraveling enhanced brain delivery of paliperidone-loaded lipid nanoconstructs: pharmacokinetic, behavioral, biochemical, and histological aspects

Antipsychotics are accompanied by extrapyramidal side effects that deter treatment adherence and patient compliance. Paliperidone (PPD), an atypical (second-generation) antipsychotic recommended for managing schizophrenia presents biopharmaceutical challenges and pharmacological constraints which dissuade it from crossing the brain barrier. The present research aimed to assess paliperidone-loaded lipid nanoconstruct (PPD-LNC) for an improved antipsychotic activity for managing schizophrenia. High % cell viability in Neuro-2a cells (70–98%) exhibited the safety of PPD-LNC. The pharmacokinetic data showed a 3.46-fold improvement in the relative bioavailability in the brain for PPD-LNC compared to a drug suspension. The pharmacodynamic evaluation demonstrated a significant (p < .05) reduction in cataleptic behavior, attenuated escape latency, and prolonged stay in the open arm with PPD-LNC, thus showing its effectiveness in reducing extrapyramidal symptoms. The histopathological images further validated the safety of the formulation. Reduction in NF-κB levels as identified by immunohistochemical analysis exhibited the anti-inflammatory effect of PPD-LNC. The formulation demonstrated significant (p < .01) improvement in the activity of oxidative stress parameters and attenuation of neuroinflammatory markers. Based on the study findings, it was observed that formulating LNC of PPD would surmount the pharmacological constraints, improve the in vivo performance, and diminish the associated side effects.

Putative neuroprotective pharmacotherapies to target the staged progression of mental illness

AIM

Neuropsychiatric disorders including depression, bipolar and schizophrenia frequently exhibit a neuroprogressive course from prodrome to chronicity. There are a range of agents exhibiting capacity to attenuate biological mechanisms associated with neuroprogression. This review will update the evidence for putative neuroprotective agents including clinical efficacy, mechanisms of action and limitations in current assessment tools, and identify novel agents with neuroprotective potential.

METHOD

Data for this review were sourced from online databases PUBMED, Embase and Web of Science. Only data published since 2012 were included in this review, no data were excluded based on language or publication origin.

RESULTS

Each of the agents reviewed inhibit one or multiple pathways of neuroprogression including: inflammatory gene expression and cytokine release, oxidative and nitrosative stress, mitochondrial dysfunction, neurotrophin dysregulation and apoptotic signalling. Some demonstrate clinical efficacy in preventing neural damage or loss, relapse or cognitive/functional decline. Agents include: the psychotropic medications lithium, second generation antipsychotics and antidepressants; other pharmacological agents such as minocycline, aspirin, cyclooxygenase-2 inhibitors, statins, ketamine and alpha-2-delta ligands; and others such as erythropoietin, oestrogen, leptin, N-acetylcysteine, curcumin, melatonin and ebselen.

CONCLUSIONS

Signals of evidence of clinical neuroprotection are evident for a number of candidate agents. Adjunctive use of multiple agents may present a viable avenue to clinical realization of neuroprotection. Definitive prospective studies of neuroprotection with multimodal assessment tools are required.

High doses of antipsychotic polypharmacy are related to an increase in serum levels of pentosidine in patients with schizophrenia

BACKGROUND

Carbonyl stress in patients with schizophrenia has been reported to be reflected by an increase in peripheral pentosidine levels. This cohort study tested whether the accumulation of pentosidine was related to the disease severity or the treatment (routine administration of high antipsychotic doses).

METHODS

We followed up our original investigation using a new group of 137 patients with acute schizophrenia and 45 healthy subjects, and then pooled the two cohorts to conduct the following analysis on a total of 274 patients. The associations of serum pentosidine and pyridoxal levels with duration of education, estimated duration of medication, the severity of symptoms, and daily doses of antipsychotics, antiparkinsonian drugs, and anxiolytics were evaluated by multiple linear regression analysis.

RESULTS

The combined cohort of 274 patients exhibited abnormally high serum levels of pentosidine, were associated with a higher daily dose of antipsychotic drugs and a longer estimated duration of medication without statistical significance of diagnosis. This was also observed in the patients treated with antipsychotic polypharmacy, but the serum pentosidine levels of patients treated with first- or second-generation antipsychotic monotherapy showed no relationship with these two variables.

CONCLUSION

High levels of serum pentosidine were associated with high daily doses of antipsychotic drugs and a longer estimated duration of medication in patients treated with antipsychotic polypharmacy.