Ultra-sensitive detection of tizanidine in commercial tablets and urine samples using zinc oxide coated glassy carbon electrode

Abstract

Tizanidine hydrochloride (TZD) is a muscle relaxant and alpha2 adrenergic agonist. TZD overdose possesses some potentially unwanted side effects including hallucinations, delusion, low blood pressure, liver damage, etc. Thus, the development of an analytical method for the sensitive detection of TZD in clinical and real samples is essential. Zinc oxide (ZnO) is a non-hazardous material and its amazing surface properties, and wide bandgap makes it a good modifier for electrochemical sensor development. In the present work, a novel sensor system is developed for the electrochemical determination of TZD. The fabrication of the glassy carbon electrode (GCE) was done by the drop cast method, where suspension of ZnO was coated on the sparkling surface of the GCE. Voltammetric investigation of TZD was performed by employing cyclic voltammetry (CV), linear sweep voltammetry (LSV), and square wave voltammetry (SWV) techniques. The electroanalytical study of TZD shows one peak in the forward scan indicating the irreversibility of TZD at bare GCE and ZnO/GCE. In comparison to bare GCE, sensitive detection with a higher peak current was obtained at the modified electrode, due to the increase in the active surface area. Optimization of the amount of modifier, accumulation time, and pH of the electrolyte was done methodically. The analytical performance of the fabricated sensor towards TZD detection was investigated by using the SWV technique, and the limit of detection was found to be 1.15 × 10−8 M. To check the effectiveness and real-time application, the developed electrode was assessed in the detection of TZD in commercially available pharmaceutical formulations and TZD spiked human urine samples. The fabricated sensor has also shown a sensitive detection and higher % recovery values, indicating its direct commercial and clinical importance.