Ranolazine (RZ) is an anti-anginal drug with a distinct mechanism of action and widely employed in patients with chronic angina. Its measurement is essential in clinical environment to ensure adequate drug level and understand the redox mechanism which gives an idea of in-vivo fate of the drug. In view of this, an exemplary voltammetric approach is proposed here for determination of RZ utilizing glassy carbon electrode (GCE) fabricated with WO3 decorated graphene nanocomposite. The structural and morphological characterizations of modifier were made by employing XRD, FESEM, EDAX, HRTEM, XPS, Raman and FT-IR spectroscopy which revealed successful formation of the nanocomposite. As a result of high electrical conductivity and large effective surface area of WO3 nanoparticles and graphene nanosheets, the developed sensor WO3/Graphene/GCE displayed effectual and unrelenting electron interceding behavior exhibiting higher peak currents at lower potentials for RZ oxidation. Using square wave voltammetry, the drug showcased well-defined voltammetric response in Britton-Robinson buffer at pH 4.5 in concentration range from 0.2-1.4 μM and 1.4-14 μM with the low detection limit of 0.13 μM. The developed protocol was then implemented successfully to quantify RZ in commercially accessible pharmaceutical tablets with satisfactory recovery (99.8%-100.2%). The experimental results illustrated the applicability of the fabricated sensor for drug quality control and clinical analysis along with pharmacokinetic studies.
In present work, we demonstrate a single step environmentally benign approach to synthesize Au/Ag bimetallic nanoparticles (BMNPs) using aqueous extract of Clove buds for the first time. Clove bud's (CB) extract has proficiency to act as a reducing and stabilizing agent for the formation of Au/Ag BMNPs. In presence of extract, AuIII and AgI are reduced competitively within same solution and produce Au/Ag alloy NPs. The kinetics besides the formation of NPs was studied using UV-visible spectroscopy and efficiency of the extract was monitored by varying contact time, temperature, pH and extract concentration. The electron microscopic studies revealed the presence of NPs with peculiar morphology at alkaline pH. Further, the existence of Au and Ag atoms was investigated using energy dispersive X-ray (EDX), X-ray diffraction (XRD) and cyclic voltammetry (CV) techniques. Fourier transform infrared spectroscopy (FTIR) showed that Eugenol in the extract is mainly responsible for the production of NPs which are also surrounded by various phytochemicals. Zeta potential of all the NPs is found to be negative which prevents their agglomeration due to inter-repulsion and the biosynthesized Au/Ag BMNPs revealed greater catalytic efficiency for the degradation of methyl orange (MO), methylene blue (MB) and reduction of p-nitrophenol (p-NP). Significant enhancement induced by BMNPs compared to individual monometallic nanoparticles (MMNPs) was assigned to the synergistic effect of MMNPs and coating of phytochemicals present in the CB extract.
In the present work, a chemically modified electrode has been fabricated utilizing Bi2O3/ZnO nanocomposite. The nanocomposite was synthesized by simple sonochemical method and characterized for its structural and morphological properties by using XRD, FESEM, EDAX, HRTEM and XPS techniques. The results clearly indicated co-existence of Bi2O3 and ZnO in the nanocomposite with chemical interaction between them. Bi2O3/ZnO nanocomposite based glassy carbon electrode (GCE) was utilized for sensitive voltammetric detection of an anti-biotic drug (balofloxacin). The modification amplified the electroactive surface area of the sensor, thus providing more sites for oxidation of analyte. Cyclic and square wave voltammograms revealed that Bi2O3/ZnO modified electrode provides excellent electrocatalytic action towards balofloxacin oxidation. The current exhibited a wide linear response in concentration range of 150-1000 nM and detection limit of 40.5 nM was attained. The modified electrode offered advantages in terms of simplicity of preparation, fair stability (RSD 1.45%), appreciable reproducibility (RSD 2.03%) and selectivity. The proposed sensor was applied for determining balofloxacin in commercial pharmaceutical formulations and blood serum samples with the mean recoveries of 99.09% and 99.5%, respectively.