A Chemically Modified Sensor for the Electroanalytical Quantification of Clomiphene Citrate in Pharmaceuticals Formulation

A sensitive electroanalytical method for quantification of clomiphene citrate in pharmaceutical formulation has been developed on the basis of the enhanced electrochemical response at glassy carbon electrode modified with nano-composite film of bismuth (III) oxide -multiwalled carbon nanotubes (Bi₂O₃-MWCNTs). A well developed anodic peak for the oxidation of clomiphene was obtained in acidic medium using BR buffer at modified and unmodified electrodes. The influence of optimisation parameters such as pH and optimal loading of composite mixture on the analytical performance of the sensor was evaluated. The morphological characteristics, effective electrode surface area and charge transfer properties of the developed Bi₂O₃-MWCNTs/GCE sensor were studied by scanning electron microscopy (SEM), cyclic voltammetry and electrochemical impedance spectroscopy (EIS) respectively. The fabricated sensor based on the Bi₂O₃-MWCNTs modified electrode showed electrocatalytic activity in terms of significant improvement of the anodic current of clomephene and lowering of the detection limit. Under optimized conditions, the squarewave oxidation peak current of clomiphene was linear over the concentration range of 50 ng mL^-1 to10 µg mL^-1. The obtained results suggest that the developed sensor can be successfully used for the determination of clomiphene in its commercial pharmaceutical formulations.