Electroanalysis of Cefadroxil Antibiotic at Carbon Nanotube/Gold Nanoparticle Modified Glassy Carbon Electrodes

Characterization and Application of a Synthesized Novel Poly(chlorobis(1,10-phenanthroline)resorcinolcobalt(II) chloride)-Modified Glassy Carbon Electrode for Selective Voltammetric Determination of Cefadroxil in Pharmaceutical Formulations, Human Urine, and Blood Serum Samples

Cefadroxil belongs to the β-lactam antibiotics, mainly used for the treatment of various bacterial infections, caused by Gram-positive and Gram-negative bacteria. However, it is also encountering serious bacterial resistance, necessitating continuous monitoring of its level in pharmaceutical and biological samples. This study presents a selective, accurate, and precise square-wave voltammetric method based on a novel poly(chlorobis(1,10-phenanthroline)resorcinolcobalt(II)chloride)-modified glassy carbon electrode (poly(CP₂RCoC)/GCE) for determination of cefadroxil (CDL). UV-vis spectroscopy, FT-IR spectroscopy, metal and halide estimation, CHN elemental analysis, and electrolytic conductivity measurement results confirmed the synthesis of the title complex modifier. Electrode characterization results revealed modification of the surface of the electrode by an electroactive and a conductive polymer film (poly(CP₂RCoC)/GCE), leading to an improved effective electrode surface area. In contrast to the bare electrode, the appearance of an irreversible oxidative peak at a much reduced potential with a 7-fold current enhancement at poly(CP₂RCoC)/GCE showed the catalytic effect of the modifier toward oxidation of CDL. The square-wave voltammetric current response of poly(CP₂RCoC)/GCE showed a linear dependence on the concentration of CDL in the range of 1 × 10^-7-3.0 × 10^-4 M with a detection limit of 4.3 × 10^-9. The CDL level in the selected two tablet brands was in the range of 97.25-100.00% of their labeled values. The spike recovery results in tablet, human blood serum, and urine samples were 98.85-101.30, 99.20-100.39, and 98.10-99.99%, respectively. Interference recovery results with a less than 4.74% error, lower LoD, and wider dynamic range than the previously reported methods validated the potential applicability of the present method with excellent accuracy and sensitivity based on the novel mixed-ligand complex-modified GCE (poly(CP₂RCoC)/GCE) for determination of CDL in various real samples with a complex matrix.

A Minireview for Recent Development of Nanomaterial-Based Detection of Antibiotics

Antibiotics are considered a new type of organic pollutant. Antibiotic residues have become a global issue due to their harm to human health. As the use of antibiotics is increasing in human life, such as in medicine, crops, livestock, and even drinking water, the accurate analysis of antibiotics is very vital. In order to develop rapid and on-site approaches for the detection of antibiotics and the analysis of trace-level residual antibiotics, a high-sensitivity, simple, and portable solution is required. Meanwhile, the rapid nanotechnology development of a variety of nanomaterials has been achieved. In this review, nanomaterial-based techniques for antibiotic detection are discussed, and some reports that have employed combined nanomaterials with optical techniques or electrochemical techniques are highlighted.

Potentiodynamic Poly(resorcinol)-Modified Glassy Carbon Electrode as a Voltammetric Sensor for Determining Cephalexin and Cefadroxil Simultaneously in Pharmaceutical Formulation and Biological Fluid Samples

This study covers the development of a fast, selective, sensitive, and stable method for the simultaneous determination of cephalosporins (cephalexin (CLN) and cefadroxil (CFL)) in biological fluids and tablet samples using potentiodynamic fabrication of a poly(resorcinol)-modified glassy carbon electrode (poly(reso)/GCE). The results of cyclic voltammetry and electrochemical impedance spectroscopy supported the modification of the GCE by a polymer layer that raised the electrode surface area and conductivity. At the poly(reso)/GCE, an irreversible oxidative peak with four- and fivefold current enhancement for CLN and CFL, respectively, at a substantially lower potential demonstrated the catalytic action of the modifier. Under optimized solution and parameters, the peak current response at the poly(reso)/GCE revealed a linear dependence on the concentration of CLN and CFL within the range 0.1-300 and 0.5-300 μM, respectively, with a limit of detection (LoD) of 3.12 and 8.7 nM, respectively. The levels of CLN in four selected tablet brands and CFL in two tablet brands were in the vicinity of 91.00-103.65% and 97.7-98.83%, respectively, of their nominal values. The recovery results for CLN in pharmaceutical samples were in the range of 99.00-100.67% and for CFL 97.9-99.75% and for blood serum and urine samples 99.55-100.55% and 99.33-100.34% for CLN and 97.13-100.60% and 96.73-102.50% for CFL, respectively. Interference recovery results with errors less than 4.81%, lower LoD, wider dynamic range, excellent recovery results, and good stability of the modifier compared to those for the previously reported methods validated the use of the poly(reso)/GCE for determining CLN and CFL simultaneously in various real samples.

Application of a Conducting Poly-Methionine/Gold Nanoparticles-Modified Sensor for the Electrochemical Detection of Paroxetine

This work demonstrates a facile electropolymerization of a dl-methionine (dl-met) conducting polymeric film on a gold nanoparticle (AuNPs)-modified glassy carbon electrode (GCE). The resulting sensor was successfully applied for the sensitive detection of paroxetine·HCl (PRX), a selective serotonin (5-HT) reuptake inhibitor (SSRIs), in its pharmaceutical formulations. The sensor was characterized morphologically using scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) and electrochemical techniques such as differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The proposed sensor, poly (dl-met)/AuNPs-GCE, exhibited a linear response range from 5 × 10⁻¹¹ to 5 × 10⁻⁸ M and from 5 × 10⁻⁸ to 1 × 10⁻⁴ M using DPV with lowest limit of detection (LOD = 1 × 10⁻¹¹ M) based on (S/N = 3). The poly (dl-met)/AuNPs-GCE sensor was successfully applied for PRX determination in three different pharmaceutical formulations with percent recoveries between 96.29% and 103.40% ± SD (±0.02 and ±0.58, respectively).