Electrochemical Behavior of Carvedilol and Its Adsorptive Stripping Determination in Dosage Forms and Biological Fluids

Green fabrication of 3D hierarchical blossom-like hybrid of peeled montmorillonite-ZnO for in-vitro electrochemical sensing of diltiazem hydrochloride drug

Herein, a 3D hierarchical blossom-like of Montmorillonite-ZnO (MMt/ZnO) micro-hybrids modified sensors have been successfully fabricated as an extraordinarily electrochemical sensor for detecting of the Diltiazem hydrochloride (DZM.HCl). The 3D hierarchical blossom-like of ZnO and series of MMt/ZnO hybrids have been synthesized using different contents of MMt [FMZ_1-5] via a hydrogel polymer template method using alginate ions. The effect of incorporation of different contents of MMt on the morphology, surface area of hybrids were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET) surface area method, and High-resolution transmission electron microscopy (HR-TEM). The obtained hybrid [FMZ₃] with 2.0% of MMt presented the most perfect blossom-like morphology and the highest surface area (190.06 m²/g) with the lowest resistivity. The hierarchical structure of [FMZ₃] reveals nanospheres of ZnO with an average diameter of 5.49 nm, which are assembled into nanorods followed by assembling to form a blossom-like shape with the inclusion of MMt peeled layers inside the rod with d-spacing ranges from 1.1-7.4 nm. Meanwhile, the implemented modified sensor 1.0% [FMZ₃] CPS retained excellent conductivity and electrocatalytic activity as appraised from the cyclic voltammetry (CV) measurements. Consequently, the electrochemical behavior and the oxidation mechanism of DZM.HCl drug has been investigated at the surface of the constructed sensor. Under the optimum operational conditions, the proposed sensor was successfully achieved detection limits 0.177, and 0.21 nmol·L^-1 of DZM.HCl in a commercial and human biological fluid (Serum samples), respectively. The constructed sensor accomplished an appropriate accuracy and free of obstruction from other ordinarily drug excipients.

Development of Electrochemical Sensor Based on Carbonaceal and Metal Phthalocyanines Materials for Determination of Ethinyl Estradiol

This work describes the development of an electrochemical sensor that was used in the determination of ethinyl estradiol (EE) in pharmaceutical formulations, river water, and milk using the square wave voltammetry technique. Studies were carried out using different carbonaceous materials (multiwalled carbon nanotubes, reduced graphene oxide Reduced graphene oxide, graphite) and different metallic phthalocyanines (cobalt, iron and manganese). Based on these studies it was possible to obtain the best system for the construction of the sensor. The device was obtained by the chemical modification of a glassy carbon electrode (GCE) with multiwalled carbon nanotubes (MWCNTs) and cobalt phthalocyanine (CoPc). The materials were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Under conditions previously optimized for the proposed method, an analytical curve was constructed, presenting linearity in a range of 2.50–90.0 μmol L−1 (R = 0.990), with detection limit of 2.20 μmol L−1 and quantification of 2.50 μmol L−1. The validation of the methodology for the determination of EE using GCE-MWCNTs-CoPc was performed, being accurate, precise, stable and sensitive. The recovery of ethinyl estradiol in the sample of pharmaceutical formulation was 103.93%, in the samples of river water ranged from 92.75% to 96.47%, and in the milk sample was from 88.00% to 96.20%. Thus, the proposed method presented a viable alternative for the determination of ethinyl estradiol in the quality control of pharmaceutical and food formulations as well as in environmental control.

A sensitive electrochemical sensor for the determination of carvedilol based on a modified glassy carbon electrode with ordered mesoporous carbon

This work describes the incorporation of ordered mesoporous carbon (OMC) as a sensing material for carvedilol (CAR) detection on a glassy carbon electrode (GCE).

Dispersive liquid–liquid microextraction based on solidification of floating organic droplet followed by spectrofluorimetry for determination of carvedilol in human plasma

Background: Simple, chip and rapid analytical methods are required in biomedical analysis laboratories to support therapeutic drug monitoring units in hospitals. The present work aimed to provide such a method for quantitative determination of carvedilol in plasma samples. Results: A new, simple, precise and efficient method was developed for the determination of carvedilol in human plasma using a dispersive liquid–liquid microextraction based on solidification of floating organic droplet, followed by spectrofluorimetry method. Some important parameters such as types and volumes of extraction and disperser solvents, pH, salt effect and sample volume were optimized. Under the optimized experimental conditions, the method provided a linear range of 40 to 300 ng ml-1, with a correlation coefficient of 0.996. The limit of detection, lower limit of quantification and upper limit of quantification were 18, 40 and 300 ng ml-1, respectively. The found recovery was from 98.2 to 102.2%, the mean intra- and inter-day precisions were 8.3 and 6.4%, respectively. The relative error for accuracy varied from 0.4 to 2.2%. The short-term temperature and freeze–thaw stability studies showed that carvedilol in human plasma was stable for sample preparation and analysis after storage. Conclusion: The proposed method provided reasonable acceptable results and could be used for therapeutic monitoring of carvedilol.

Electrochemical Behavior of Biologically Important Indole Derivatives

Voltammetric techniques are most suitable to investigate the redox properties of a new drug. Use of electrochemistry is an important approach in drug discovery and research as well as quality control, drug stability, and determination of physiological activity. The indole nucleus is an essential element of a number of natural and synthetic products with significant biological activity. Indole derivatives are the well-known electroactive compounds that are readily oxidized at carbon-based electrodes, and thus analytical procedures, such as electrochemical detection and voltammetry, have been developed for the determination of biologically important indoles. This paper explains some of the relevant and recent achievements in the electrochemistry processes and parameters mainly related to biologically important indole derivatives in view of drug discovery and analysis.