A new strategy for the determination of the antidiabetics alogliptin, saxagliptin and vildagliptin using all-solid state potentiometric sensors.

Herein, we report on the development of disposable screen printed carbon, nanostructure thin film Au/Pt and Pt/Pt all-solid state potentiometric sensors for some antidiabetic compounds called glibtins. The electrodes showed excellent calibration curves (1 × 10-5-1 × 10-2 M) for alogliptin, saxagliptin and vildagliptin. The electrodes were fully characterized with respect to potential stability, dynamic response time, detection limit, effect of pH and interference according to the IUPAC recommendation. The proposed method is rapid and can be applied for the determination of gliptins at low cost with satisfactory precision (RSD ≤ 1%) and accuracy.

Solid-state ion-selective electrodes for the first potentiometric determination of the anti-COVID 19 drug Remdesivir in human plasma; A comparative study.

Establishing sensitive and targeted analytical methodologies for drug identification in biological fluids as well as screening of treatments that can counteract the most severe COVID-19 infection-related side effects are of utmost importance. Here, first attempts have been made for determination of the anti-COVID drug Remdesivir (RDS) in human plasma using four potentiometric sensors. Calixarene-8 (CX8) was used as an ionophore applied to the first electrode (Sensor I). The second had a layer of dispersed graphene nanocomposite coating (Sensor II). (Sensor III) was fabricated using nanoparticles of polyaniline (PANI) as ion-to-electron transducer. A reverse-phase polymerization using polyvinylpyrrolidone (PVP) was employed to create a graphene-polyaniline (G/PANI) nanocomposite electrode (Sensor IV). Surface morphology was confirmed by Scanning Electron Microscope (SEM). UV absorption spectra and Fourier Transform Ion Spectrophotometry (FTIR) also supported their structural characterization. The impact of graphene and polyaniline integration on the functionality and durability of the manufactured sensors was examined using the water layer test and signal drift. In the ranges of concentration of 10-7 to 10-2 mol/L and 10-7 to 10-3, sensors II & IV exhibited linear responses; respectively while sensors I & III displayed linearity within 10-6 to 10-2 mol/L. The target drug was easily detectable using LOD down to 100 nmol/L. The developed sensors satisfactorily offered sensitive, stable, selective and accurate estimate of Remdesivir (RDS) in its pharmaceutical formulation as well as spiked human plasma with recoveries ranging from 91.02 to 95.76 % with average standard deviations less than 1.85. The suggested procedure was approved in accordance with ICH recommendations.

Voltammetric Determination of Sulfaclozine Sodium at Sephadex-modified Carbon Paste Electrode.

The electrochemical behavior of Sulfaclozine Sodium (SLC) was studied at a bare and sephadex-modified carbon paste electrodes by cyclic voltammetry and square wave voltammetry. The cyclic voltammetry (CV) showed a well-defined irreversible oxidation peak at 0.94 V in Britton- Robinson buffer pH 7.0. The strong affinity of SLC to sephadex allowed accumulation of SLC at the surface of electrode and thus higher electrochemical sensitivity to SLC. The influence of sephadex loading, the pH of the solution and the scan rate on the peak current was studied. A linear calibration curve covering the concentration range from 0.005 to 1 mM was obtained using SWV. The method was successfully applied for the determination of SLC in the veterinary pharmaceutical formulations with satisfactory accuracy and precision.

Comparative Study of Univariate Spectrophotometry and Multivariate Calibration for the Determination of Levamisole Hydrochloride and Closantel Sodium in a Binary Mixture.

Six simple, accurate, reproducible, and selective derivative spectrophotometric and chemometric methods have been developed and validated for the determination of levamisole HCl (Lev) either alone or in combination with closantel sodium (Clo) in the pharmaceutical dosage form. Lev was determined by first-derivative, first-derivative ratio, and mean-centering methods by measuring the peak amplitude at 220.8, 243.8, and 210.4 nm, respectively. The methods were linear over the concentration range 2.0-10.0 µg/mL Lev. The methods exhibited a high accuracy, with recovery data within ±1.9% and RSD <1.3% (n = 9) for the determination of Lev in the presence of Clo. Fortunately, Lev showed no significant UV absorbance at 370.6 nm, which allowed the determination of Clo over the concentration range 16.0-80.0 µg/mL using zero-order spectra, with a high precision (RSD <1.5%, n = 9). Furthermore, principal component regression and partial least-squares with optimized parameters were used for the determination of Lev in the presence of Clo. The recovery was within ±1%, with RSD <1.0% (n = 9) and root mean square error of prediction ≤1.0. The proposed methods were validated according to the International Conference on Harmonization guidelines. The proposed methods were used in the determination of Lev and Clo in a binary mixture and a pharmaceutical formulation, with high accuracy and precision.