Determinação voltamétrica de hidroxizina e do seu principal metabólito cetirizina em fluidos corporais usando um sensor nanoestruturado de carbon black

Hydroxyzine (HDZ) is a piperazine antihistamine usedin the treatment of bronchial asthma. Cetirizine (CET) is an active metabolite of HDZ belongs to the second generation of antihistamines. In this work, novel voltammetric methodsweredeveloped for individualdetermination of HDZ and its main metabolite CET in body fluids using a modified glassy carbon electrode with carbon black (CB-GCE).These proposed methods are very attractive, since there are few electroanalytical methods reported in the literature for HDZ and CET determination. On the modified CB-GCEa very sharp oxidation process was verified during the anodic potential scanning in both the cases, localized at +0.97V(HDZ)and +1.07 V (CET) vs. Ag/AgCl (3.0 mol L−1KCl), respectively. On the other hand, using the bare GCE, there are no occurrence of an anodic peak well defined for both analytes. Thus, the incorporation of carbon black on the GCE surface improved significantly(about twenty times)the voltammetric response of HDZ (Fig.1a) and cetirizine (Fig.1b). Moreover, theanodic peak potential of HDZ was shifted 70mV,showing the electrocatalytic activity of the nanostructured carbon blackfilm. Under optimized conditions, the developed square-wave adsorptive anodic stripping voltammetry (SWAdASV) method presented analytical curves linear inthe concentration rangesof2.99 × 10−7 to 9.81 × 10−6mol L−1(HDZ)and of 4.97 × 10−7 to 1.08 × 10−5mol L−1 (CET) with detection limits of 1.00× 10−7 and4.00× 10−7 molL−1, respectively.The proposed method was exploredto estimate the amounts of both analytes in synthetic cerebrospinal fluid and urine samples. Furthermore, using nuclear magnetic resonance (NMR) measurements, after exhaustion potentiostatic electrolysis ofCET,the oxidation products were obtained and then anelectrooxidation of CET reaction was proposed.