Graphene-polyaniline nanocomposite based biosensor for detection of antimalarial drug artesunate in pharmaceutical formulation and biological fluids

Bioactive electrode of dispersed graphene oxide in polyaniline composite was electrochemically fabricated onto indium tin oxide substrate for pharmaceutical application. Formations of nanocomposite graphene-polyaniline matrix with diameter 67.99 nm were observed with the use of scanning electron microscope and high resolution transmission electron microscope. Electrochemical interfacial properties and immobilization of enzyme onto the graphene-polyaniline electrode have been evaluated and confirmed with the use of Fourier transform infrared spectroscopic, cyclic voltammetry and electrochemical impedance spectroscopic techniques. The graphene-polyaniline-horseradish peroxidase biosensor was further used for sensing artesunate a potent antimalarial drug. The biosensor shows linearity of 0.05-0.40 ng mL−1 of artesunate with sensitivity of 0.15 µA ng mL−1. The procedure was applied to the assay of the drug in dosage form, human serum, plasma and urine without matrix interference. The limits of detection for parenteral artesunate, human urine, human serum and human plasma were 0.012 ng mL−1, 0.013 ng mL−1, 0.014 ng mL−1 and 0.014 ng mL−1 respectively. The mean percentage recoveries obtained were in the range from 98.23% to 100.3% for parental drug, urine, serum and plasma samples. The resultant precision and accuracy as evidenced have shown a promising selectivity in their application.