Voltammetric behaviour of drotaverine hydrochloride in surfactant media and its enhancement determination in Tween-20

Smart green spectrophotometric assay of the ternary mixture of drotaverine, caffeine and paracetamol in their pharmaceutical dosage form

Three green and facile spectrophotometric methods were developed for the assay of Petro® components; drotaverine HCl (DRT), caffeine (CAFF), and paracetamol (PAR). The three methods depend on measuring the absorbance of the studied drugs through their ethanolic solution. The first derivative spectrophotometry (FDS) at (Δλ = 10) were good parameters for DRT and CAFF resolution; DRT and CAFF could be well calibrated using FDS at 320 and 285 nm, respectively. PAR could be estimated at 308 nm utilizing the second derivative spectrophotometry (SDS). Method II relies on the double divisor ratio derivative spectroscopy (DDRDS). The first derivative was applied on each drug where they would be assayed at 309, 288, and 255 nm for DRT, CAFF, and PAR, respectively. Method III depends on the mean centering (MCR) technique. DRT, CAFF, and PAR could be determined at 309, 214, and 248 nm, respectively. The concentrations were rectilinear in the ranges of 2-20 µg/mL for DRT, 1.5-15 µg/mL for CAFF, and 2-40 µg/mL for PAR in double devisor and mean centering but PAR from 5 to 40 µg/mL in derivative method. Method validation was performed according to ICH guidelines assured by the agreement with the comparison method. In addition, greenness assessment of the proposed methods was investigated. The application of the proposed method was extended to analyse tablet dosage form and performing invitro dissolution testing.

Computer-Aided Design of Eco-Friendly Imprinted Polymer Decorated Sensors Augmented by Self-Validated Ensemble Modeling Designs for the Quantitation of Drotaverine Hydrochloride in Dosage Form and Human Plasma

BACKGROUND

Computationally designed molecular imprinted polymer (MIP) incorporation into electrochemical sensors has many advantages to the performance of the designed sensors. The innovative self-validated ensemble modeling (SVEM) approach is a smart machine learning-based (ML) technique that enables the design of more accurate predictive models using smaller data sets.

OBJECTIVE

The novel SVEM experimental design methodology is exploited here exclusively to optimize the composition of four eco-friendly PVC membranes augmented by a computationally designed magnetic molecularly imprinted polymer to quantitatively determine drotaverine hydrochloride (DVN) in its combined dosage form and human plasma. Furthermore, the application of hybrid computational simulations such as molecular dynamics and quantum mechanical calculations (MD/QM) is a time-saving and eco-friendly provider for the tailored design of the MIP particles.

METHOD

Here, for the first time, the predictive power of ML is assembled with computational simulations to develop four PVC-based sensors decorated by computationally designed MIP particles using four different experimental designs known as central composite, SVEM-LASSO, SVEM-FWD, and SVEM-PFWD. The pioneering AGREE approach further assessed the greenness of the analytical methods, proving their eco-friendliness.

RESULTS

The proposed sensors showed decent Nernstian responses toward DVN in the range of 58.60-59.09 mV/decade with a linear quantitative range of 1 × 10-7 - 1 × 10-2 M and limits of detection in the range of 9.55 × 10-8 to 7.08 × 10-8 M. Moreover, the proposed sensors showed ultimate eco-friendliness and selectivity for their target in its combined dosage form and spiked human plasma.

CONCLUSIONS

The proposed sensors were validated in accordance with International Union of Pure and Applied Chemistry (IUPAC) recommendations, proving their sensitivity and selectivity for drotaverine determination in dosage form and human plasma.

HIGHLIGHTS

This work presents the first ever application of both the innovative SVEM designs and MD/QM simulations in the optimization and fabrication of drotaverine-sensitive and selective MIP-decorated PVC sensors.

Highly Sensitive Non-Enzymatic Detection of Glucose at MWCNT-CuBTC Composite Electrode

A novel electrochemical glucose sensor was developed, based on a multiwall carbon nanotubes (MWCNTs)-copper-1,3,5-benzenetricarboxylic acid (CuBTC)-epoxy composite electrode, named MWCNT-CuBTC. The electrode nanocomposite was prepared by a two-roll mill procedure and characterized morphostructurally by scanning electron microscopy (SEM). The CuBTC formed defined crystals with a wide size distribution, which were well dispersed and embedded in the MWCNTs. Its electrical conductivity was determined by four-point probe contact (DC) conductivity measurements. The electroactive surface area, determined using cyclic voltammetry (CV), was found to be 6.9 times higher than the geometrical one. The results of the electrochemical measurements using CV, linear sweep voltammetry (LSV), differential pulse voltammetry (DPV), chronoamperometry (CA) and multiple pulse amperometry (MPA) showed that the MWCNT-CuBTC composite electrode displayed high electrocatalytic activity toward the oxidation of glucose and, as a consequence, very high sensitivity. The best sensitivity of 14,949 µAmM−1cm−1 was reached using MPA at the potential value of 0.6 V/SCE, which was much higher in comparison with other copper-based electrodes reported in the literature. The good analytical performance, low cost and simple preparation method make this novel electrode material promising for the development of an effective glucose sensor.

Voltammetric determination of cefpirome at multiwalled carbon nanotube modified glassy carbon sensor based electrode in bulk form and pharmaceutical formulation

A new, simple and low cost voltammetric method for the determination of cefpirome in pharmaceutical preparations has been developed using multiwalled carbon nanotube modified glassy carbon electrode (MWCNT), which showed stable response with enhanced selectivity and sensitivity over the bare glassy carbon electrode. A multiwalled carbon nanotube (MWCNT) modified glassy carbon electrode (GCE) is used for the simultaneous determination of cefpirome by differential pulse voltammetry and square wave voltammetry. Results indicated that cathodic peak of cefpirome is greatly improved at MWCNT modified GC electrode as compared with the bare GC electrode showing excellent electrocatalytic activity towards cefpirome reduction. Linear calibration curves are obtained over the concentration range 100-600 μg mL(-1) in Britton Robinson buffer at pH 4.51 with limit of detection (LOD) and limit of quantification (LOQ) are 0.647 μg mL(-1) and 2.159 μg mL(-1) using SWV and 5.540 μg mL(-1) and 18.489 μg mL(-1) using DPV, respectively. The described method is rapid and can be successfully applied for the determination of cefpirome in bulk form and pharmaceutical formulations.

Voltammetric determination of some alkaloids and other compounds in pharmaceuticals and urine using an electrochemically activated glassy carbon electrode

Electrochemical behaviour of some alkaloids, namely: caffeine, aminophylline, theophylline, codeine phosphate and papaverine hydrochloride, that are in solution in various combinations or in the presence of other compounds contained in pharmaceuticals or in real samples (urine) was investigated using cyclic voltammetry (CV), square-wave voltammetry (SWV) and differential pulse voltammetry (DPV) on electrochemically activated glassy carbon electrode. The proposed electroanalytical methods were successfully applied in the simultaneous determination of these alkaloids in different combination or in the presence of other compounds. The great part of these combinations can be analyzed simultaneously because they practically do not interfere. The electrochemical test methods attempted to detect the presence of alkaloids in urine samples collected from subjects who consumed coffee (caffeine), and from a patient under treatment with Miofilin® (aminophylline). Urine samples were determined after filtration, without prior dilution and after dilutiion with acetate buffer at pH 4.5. Best results were obtained using DPV performed on electrochemically activated glassy carbon electrode. Thus in samples taken from subjects who drink coffee the caffeine concentration detected was 6.21×10−7 mol L−1 in the first sample and 7.77×10−7 mol L−1 in the second sample, while aminophylline concentration detected was 1.15×10−7 mol L−1.