Electrochemical Behavior and Determination of Clozapine on a Glassy Carbon Electrode Modified by Electrochemical Oxidation

Abstract

The adsorptive and electrochemical behaviors of clozapine (CLZ) were investigated on a glassy carbon electrode that was electrochemically treated by anodic oxidation at +1.8 V, following potential cycling in the potential range from -0.8 to 1.0 V vs. Ag/AgCl reference electrode. Based on the obtained electrochemical results, an electrochemical-chemical (EC) mechanism was proposed to explain the electrochemical oxidation of CLZ. The resulting electrochemically pretreated glassy carbon electrode (EPGCE) showed good activity to improve the electrochemical response of the drug. CLZ was accumulated in a phosphate buffer (pH 6) at a certain time, and then determined by differential pulse voltammetry. The anodic and cathodic peak currents showed a linear function in the concentration ranges of 0.1 -1, 1 -10 and 10 -100 μM with various accumulation times. The proposed method was successfully used for the determination of CLZ in pharmaceutical preparations. The preconcentration medium-exchange approach was utilized for the selective determination of the drug in spiked urine samples with satisfactory results. The recovery levels of the method reached 96% (RSD, 1.8%) and 90% (RSD, 2.8%) for urine and plasma samples, respectively.

Electrochemical Detection of Benzodiazepines, Following Liquid Chromatography, for Applications in Pharmaceutical, Biomedical and Forensic Investigations

“…However, some, such as the 3H-1,5-benzodiazepines [25] have been shown to undergo two 2e -, 2H + reductions at their azomethine groups. The dibenzo substituted benzodiazepines such as clozapine (scheme I) undergo a reversible 2e -, H + redox reaction involving a relatively stable nitrenium ion [26,27].…”

Electrochemical Characterization of New 1,5-Benzodiazepine Derivatives

“…In addition to the other electrochemically active groups present in BZP core, such as, nitro, N-oxide and carbonyl groups, the drugs bearing the 1,4-benzodiazepine core are characterized by the presence of a relatively easily reducible azomethine 5 moiety, many of the therapeutic 1,5-benzodiazepines, such as clobazam are reported to be electrochemically inactive 6 , however, some others, such as the 3H-1,5-benzodiazepines 7 has been shown to undergo two 2e-, 2H + reductions at their azomethine moieties. Also, the dibenzo-substituted benzodiazepines such as clozapine undergo a reversible 2e-, H+ redox reaction involving a relatively stable nitrenium ion 8,9 .…”

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

“…The electrochemical behavior of CLZ was evaluated, and several polarographic and voltammetric methods have been reported for the electrochemical study of CLZ in literature [13][14][15][16][17][18].…”