Electrochemical study of atenolol at a carbon paste electrode modified with mordenite type zeolite

An ultra-sensitive laccase/polyaziridine-bismuth selenide nanoplates modified GCE for detection of atenolol in pharmaceuticals and urine samples

The analysis of β-blockers in pharmaceutical, biological and environmental samples has gained much interest due to their wide applications. The aim of this study was to develop an enzyme-based biosensor using hexagonal-shaped low-dimensional Bi₂Se₃ NPs decorated with laccase through polyaziridine (PAZ) modified glassy carbon electrode (Lac/PAZ-Bi₂Se₃ NPs/GCE). Surface properties were examined using SEM, TEM, EDX, XRD, XPS, FTIR, UV-Visible, and zeta potential. Electrochemical studies were performed with cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The enzymatic biosensor exhibited excellent catalytic activity towards the oxidation of ATN at +1.05 V (vs Ag/AgCl). Under the optimum experimental conditions, I_p (µA) was linearly related to the concentrations of ATN in the range of 3 to 130 µM (R² = 0.9972) with an LOD of 0.15 µM and 0.21 µM with and without Lac enzyme. Additionally, the validation of the biosensor was tested to determine ATN on within a day and between-day basis. The biosensor was applied successfully to detect ATN in real samples. The obtained recoveries range from 98.5 % to 99.2 % with an RSD (n = 5) of 0.95 (±0.02). The findings of this study have potential biomedical applications in drug detection employing a promising nano electrode sensor of Lac/PAZ-Bi₂Se₃ NPs/GCE.

Electrochemical determination of atenolol and propranolol using a carbon paste sensor modified with natural ilmenite

In this study, a simple voltammetric method was reported for independent determination of propranolol (PROP) and atenolol (ATN) in pharmaceutical tablets using carbon paste electrode modified with natural Ilmenite (CPE-I). The analytical performance of the modified sensor was evaluated using the square wave voltammetry and cyclic voltammetry for determination of both β(beta) blockers in 0.1 mol L−1 of sulfuric acid solution (H2SO4). The signal obtained with modified carbon paste electrode in 0.1 mol L−1 of H2SO4 showed a good electrocatalytic activity toward the oxidations of PROP and ATN compared with the bare one. The enhanced oxidation peak current response can be attributed to the catalytic effect of the ilmenite nanomaterial incorporated into the carbon paste electrode. Under optimal condition, good linear calibration curves were obtained ranging from 0.20 to 8.9 mmol L−1 for PROP and 2.0 to 9.9 µmol L−1 for ATN, with detection limits of 80 and 0.31 µmol L−1, respectively. The CPE-I sensor had good repeatability and reproducibility (RSD ≤ 3.2%) and high sensitivity for the detection of both ATN and PROP. The proposed sensor was applied for detection of these drugs in pharmaceutical tablets. The obtained results indicate that the voltammetric CPE-I sensor could be an alternative method for the routine quality control of the β blockers in complex matrices.

Voltammetric Techniques for the Analysis of Drugs using Nanomaterials based Chemically Modified Electrodes

Background:

Electroanalytical techniques play a very important role in the areas of medicinal, clinical as well as pharmaceutical research. Amongst these techniques, the voltammetric methods for the determination of drugs using nanomaterials based chemically modified electrodes (CMEs) have received enormous attention in recent years. This is due to the sensitivity and selectivity they provide on qualitative as well as quantitative aspects of the electroactive analyte under study. The aim of the present review was to discuss the work on nanomaterials based CMEs for the analysis of drugs covering the period from 2000 to present employing various voltammetric techniques for different classes of the drugs.

Methods:

The present review deals with the determination of different classes of drugs including analgesics, anthelmentic, anti-TB, cardiovascular, antipsychotics and anti-allergic, antibiotic and gastrointestinal drugs. Also, a special section is devoted for enantioanalysis of certain chiral drugs using voltammetry. The detailed information of the voltammetric determination for the drugs from each class employing various techniques such as differential pulse voltammetry, cyclic voltammetry, linear sweep voltammetry, square wave voltammetry, stripping voltammetry, etc. are presented in tabular form below the description of each class in the review.

Results:

Various nanomaterials including carbon nanotubes, graphene, carbon nanofibers, quantum dots, metal/metal oxide nanoparticles, polymer based nanocomposites have been used by researchers for the development of CMEs over a period of time. The large surface area to volume ratio, high conductivity, electrocatalytic activity and biocompatibility make them ideal modifiers where they produce synergistic effect which helps in trace level determination of pharmaceutical, biomedical and medicinal compounds. In addition, macrocyclic compounds as chiral selectors have been used for the determination of enantiomeric drugs where one of the isomers captured in the cavities of chiral selector shows stronger binding interaction for one of the enantiomorphs.

Conclusion:

arious kinds of functional nanocomposites have led to the manipulation of peak potential due to drug - nanoparticles interaction at the modified electrode surface. This has facilitated the simultaneous determination of drugs with almost similar peak potentials. Also, it leads to the enhancement in voltammetric response of the analytes. It is expected that such modified electrodes can be easily miniaturized and used as portable, wearable and user friendly devices. This will pave a way for in-vivo onsite real monitoring of single as well as multi component pharmaceutical compounds.

Simultaneous determination of nifedipine and atenolol in combined dosage forms using a boron-doped diamond electrode with differential pulse voltammetry

Combinations of nifedipine (NIF) and atenolol (ATN) are used for the treatment of arterial hypertension. Dosages values different from those presented on the label of pharmaceuticals can significantly impact a consumer’s health. To control the quality of the pharmaceuticals effectively, a method for the simultaneous determination of these both drugs using an anodically pretreated boron-doped diamond electrode coupled to differential pulse voltammetry technique was developed. The influence of supporting electrolyte, pH and scan rate on the current response of these both antihypertensives was examined to select the optimum experimental conditions. It was found that NIF and ATN provided two well-shaped and reproducible oxidation peaks at 0.97 V and 1.36 V (vs. Ag/AgCl electrode), respectively, in TRIS buffer solution (pH 8.0). At optimized differential pulse voltammetric parameters, the current response of NIF and ATN was proportionally linear in the concentration range of 3.98–107 μmol L–1 and 1.99–47.2 μmol L–1, with detection limit of 0.612 and 0.999 μmol L−1, respectively. The proposed method was successfully applied in analysis of several commercial combined dosage forms, whose accuracy was attested by good agreement of the results (paired t test at a 95% confidence level) with those obtained using high performance liquid chromatography.

A novel cysteine sensor based on modification of carbon paste electrode by Fe(II)-exchanged zeolite X nanoparticles

An electrochemical sensor based on carbon paste electrode (CPE) modified with iron(II) doped into a synthesized nano-particles of zeolite X (Fe(II)-NX/ZCME) was constructed, which is highly sensitive for detection of cysteine (Cys). The modified electrode showed an excellent electro-activity for oxidation of Cys in phosphate buffer at pH7.4. It has been found that anodic peak potential of Cys oxidation, compared with the unmodified CPE (UCPE), was shifted towards negative values at the surface of the modified electrode under the optimum condition. The peak current increased linearly with the Cys concentration in the wide range of 5.0 × 10(-9)-3.0 × 10(-3) mol L(-1). The very low detection limit was obtained to be 1.5 × 10(-10) mol L(-1). Finally, the modified electrode was used as a selective, simple and precise new electrochemical sensor for the determination of Cys in the real samples, such as pharmaceutical and biological fluids.