Voltammetric Determination of Clozapine in Pharmaceutical Formulations and Biological Fluids Using an In Situ Surfactant-Modified Carbon Ionic Liquid Electrode

Application of nickel-doped graphene nanotubes to modified GCE as a sensitive electrochemical sensor for the antipsychotic drug clozapine in spiked human blood serum samples

Clozapine (CLZ) is one of the most vital medications for managing schizophrenia, and the timely measurement of CLZ levels has been recognized as an obstacle to the wider use of CLZ. Herein, for the first time, nickel-doped graphene nanotubes (Ni@GRNT) were used to construct an electrochemical CLZ sensor by drop coating Ni@GRNT suspension on a glassy carbon electrode. The Ni@GRNT was synthesized and characterized using X‐ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The electrochemical behavior and influence of different physicochemical factors of sensing electrodes were investigated by using cyclic voltammetry, EIS technique, and differential pulse voltammetry techniques. Also, the catalytic rate constant (kcat) and the transfer coefficient (α) were calculated. The modified electrode illustrated satisfactory linear range, detection limit (LOD), reusability, and reproducibility results. At optimal experimental conditions, measurements can be performed at a broad linear dynamic range of 0.3 nmol L−1–60.0 μmol L−1 CLZ and with a LOD of 0.1 nmol L−1. The sensitivity value was estimated to be 3.06 μA µmol L−1 cm−2. Ultimately, this platform was successfully used for CLZ sensing in spiked human blood serum and tablet samples with an accuracy of > 93%.

Graphical abstract

Ultrafine Bi-Sn nanoparticles decorated on carbon aerogels for electrochemical simultaneous determination of dopamine (neurotransmitter) and clozapine (antipsychotic drug)

This present study describes the synthesis of ultrafine Bi-Sn nanoparticles decorated on carbon aerogels (Bi-Sn NP/CAG) as a nanocomposite for the electrochemical simultaneous determination of dopamine (DA) and clozapine (CLZ). The typical characterization techniques, such as XRD, Raman, BET, FT-IR, TGA, XPS, and FE-SEM/TEM, showed useful insights into the crystal phase and morphology of Bi-Sn NP/CAG. Integrated Bi-Sn NP/CAG built into a cost-effective screen printed carbon electrode (SPCE) offers a high electrochemical surface area (ECSA) compared to unmodified, Bi-Sn, and CAG/SPCEs, such that it favourably allowed the binding of DA and CLZ molecules onto the surface at the Bi-Sn/CAG, which was demonstrated by cyclic and differential pulse voltammetry techniques. As a result, the DA and CLZ sensing exhibited low detection limits (DL, 4.6 and 97.6 nM (S/N = 3)), and sensitivity (3.402 and 0.4 μA μM-1 cm-2) over a wide linear range (0.02-97.59 and 0.5-2092 μM), respectively. To go a step further, the Bi-Sn NP/CAG/SPCE was applied for the simultaneous determination of DA and CLZ which featured lower DL (23.1 and 31.3 nM (S/N = 3)), and sensitivity (0.4979 and 0.04 μA μM-1 cm-2) over a wide linear range (2-182 and 10-910 μM), respectively. The selectivity for DA and CLZ in the presence of a 10-fold concentration of their potentially interfering active species was demonstrated. Finally, this sensing methodology enables the rapid electrochemical determination of the amount of DA and CLZ in a rat brain region serum sample with successful recovery outcomes.

A Comprehensive Review on Importance and Quantitation of Atypical Antipsychotic Drugs and their Active Metabolites in Commercial Dosage Forms

Background:

Schizophrenia is a severe mental illness that affects more than twenty-one million people throughout the world. Schizophrenia also causes early death. Schizophrenia and other related psychotic ailments are controlled by the prescription of antipsychotic drugs, which act by blocking certain chemical receptors in the brain and thus relieves the symptoms of psychotic disorder. These drugs are present in the different dosage forms in the market and provided in a certain amount as per the need of the patients.

Objective:

Since such medications treat mental disorders, it is very important to have a perfect and accurate dose so that the risk factor is not affected by a higher or lower dose, which is not sufficient for the treatment. For accurate assay of these kinds of drugs, different analytical methods were developed ranging from older spectrophotometric techniques to latest hyphenated methods.

Results:

The current review highlights the role of different analytical techniques that were employed in the determination and identification of antipsychotic drugs and their metabolites. Techniques such as spectrophotometry, fluorimetry, liquid chromatography, liquid chromatography-mass spectrometry, gas chromatography, and gas chromatography-mass spectrometry employed in the method development of such antipsychotic drugs were reported in the review. Different metabolites, identified using the hyphenated techniques, were also mentioned in the review. The synthesis pathways of few of the metabolites were mentioned.

Conclusion:

The review summarizes the analyses of different antipsychotic drugs and their metabolites. A brief introduction of illnesses and their symptoms and possible medications were highlighted. Synthesis pathways of the associated metabolites were also mentioned.

Direct electrochemical detection of clozapine by RuO2 nanoparticles-modified screen-printed electrode

This study introduces the sensitive electrochemical detection of clozapine with the use of a ruthenium(iv) oxide nanoparticle (RuO₂ NP)-modified screen-printed electrode (RuO₂ NPs/SPE).

Electroanalysis of Tricyclic Psychotropic Drugs using Modified Electrodes

Background:

Tricyclic psychotropic drugs are defined as a tricyclic rings of the dibenzazepine group with the presence of sulfur and nitrogen atoms. They have been prescribed for antidepressive therapy over the years. Due to their medical importance, many analytical methods have been developed for their monitoring. However, benefits of electrochemical techniques such as costeffectiveness, fast, easy operation and non-destructiveness make them appropriate analytical methods for drug assays. Electrochemical determinations of pharmaceuticals require suitable working electrodes. During years, many electrodes are modified by a variety of modifiers and several sensors were developed based on them. In this regard, nanomaterials, due to their remarkable properties, are one of the most important choices.

Objective:

Here, the application of electroanalytical methods in the determination of electroactive tricyclic psychotropic drugs will be reviewed and the nanomaterials which are used for improvements of the working electrodes will be considered.

Electrochemical Analysis of Antipsychotics

Introduction:

Schizophrenia is seizures accompanied by severe psychotic symptoms, and a steady state of continuation in the form of periods of stagnation. Antipsychotics are now the basis of treatment for schizophrenia and there is no other molecule that is antipsychotic priority in treatment. Antipsychotics can be classified into two groups; dopamine receptor antagonists such as promazine, fluphenazine etc. and serotonin-dopamine antagonists including risperidone, olanzapine, ziprasidone, aripiprazole etc.

Materials and Methods:

Electrochemical methods have been used for the determination of antipsychotic agent just as used in the determination of many drug agents. Nearly all of the antipsychotics are electroactive and can be analyzed by electrochemical methods. Electroanalytical methods offer generally high sensitivity, are compatible with modern techniques, have low cost, low requirements, and compact design. Among the most commonly used types, there are cyclic voltammetry, differential pulse voltammetry, square wave voltammetry and linear sweep voltammetry.

Conclusion:

The aim of this review is to evaluate the main line and the advantages and uses of electroanalytical methods that employed for the determination of antipsychotic medication agents used in schizophrenia. Moreover, applications of the methods to pharmaceutical analysis of Antipsychotics upto- date is also summarized in a table.

Determination of antipsychotic drugs in hospital and wastewater treatment plant samples by gas chromatography/tandem mass spectrometry

The development and performance evaluation of a method for the simultaneous determination of six antipsychotic drugs in hospital effluents and wastewater treatment plants (WWTP) samples are herein presented. The method involves an off-line mixed mode (reversed-phase and strong cation exchange) solid phase extraction (SPE) with gas chromatography (GC) coupled to tandem mass spectrometry (MS/MS). The present methodology was validated following internationally accepted criteria, and the studied parameters included selectivity, linearity, limits of detection (LOD) and quantitation (LLOQ), instrumental limits, precision and accuracy, stability and recovery. The procedure was linear for concentrations ranging from 0.1 to 10μg/L (0.02 to 2μg/L for haloperidol), with determination coefficients higher than 0.99 for all analytes. Intra- and inter-day precision was lower than 15% for all analytes at the studied concentrations, while accuracy remained between a ±15% interval. Recoveries ranged from 31% to 83%. Low LODs were achieved, between 2 and 10ng/L, allowing a reliable identification of all analytes at trace levels, using only 50mL as sample volume. All studied parameters complied with the defined criteria and the method was successfully applied to gather preliminary results of the determination of antipsychotics on hospital effluents and on influent and effluent of WWTPs, opening perspectives for the study of their fate in the aquatic environment.

Nickel oxide nanoparticles/ionic liquid crystal modified carbon composite electrode for determination of neurotransmitters and paracetamol

Ionic liquid crystals mimic the natural bio-based ionic liquid crystals such as cell membrane structures in their interactions with drugs.

Multidimensional mapping method using an arrayed sensing system for cross-reactivity screening

When measuring chemical information in biological fluids, challenges of cross-reactivity arise, especially in sensing applications where no biological recognition elements exist. An understanding of the cross-reactions involved in these complex matrices is necessary to guide the design of appropriate sensing systems. This work presents a methodology for investigating cross-reactions in complex fluids. First, a systematic screening of matrix components is demonstrated in buffer-based solutions. Second, to account for the effect of the simultaneous presence of these species in complex samples, the responses of buffer-based simulated mixtures of these species were characterized using an arrayed sensing system. We demonstrate that the sensor array, consisting of electrochemical sensors with varying input parameters, generated differential responses that provide synergistic information of sample. By mapping the sensing array response onto multidimensional heat maps, characteristic signatures were compared across sensors in the array and across different matrices. Lastly, the arrayed sensing system was applied to complex biological samples to discern and match characteristic signatures between the simulated mixtures and the complex sample responses. As an example, this methodology was applied to screen interfering species relevant to the application of schizophrenia management. Specifically, blood serum measurement of antipsychotic clozapine and antioxidant species can provide useful information regarding therapeutic efficacy and psychiatric symptoms. This work proposes an investigational tool that can guide multi-analyte sensor design, chemometric modeling and biomarker discovery.