ELECTROCHEMICAL INVESTIGATION OF OTILONIUM BROMIDE USING BORON-DOPED DIAMOND AND GLASSY CARBON ELECTRODES
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-08-29 |
| Journal | Ankara Universitesi Eczacilik Fakultesi Dergisi |
| Authors | Leyla KaradurmuĆ, Esen Bellur Atıcı, SĂbel A. Ăzkan |
| Institutions | Adıyaman University, Ankara University |
| Citations | 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research details the first reported electrochemical method for the direct determination of Otilonium Bromide (OTB), an antispasmodic drug, utilizing Boron-Doped Diamond Electrodes (BDDE) and Glassy Carbon Electrodes (GCE).
- Novel Analytical Method: A rapid, low-cost, and highly sensitive Differential Pulse Voltammetry (DPV) technique was developed and validated for OTB quantification in buffer solutions.
- Superior Performance: The BDDE demonstrated superior analytical performance, achieving a Limit of Detection (LOD) of 4.92x10-6 M, significantly better than the GCE (1.17x10-5 M).
- Electrochemical Mechanism: The oxidation of OTB on both BDDE and GCE was determined to be an irreversible, diffusion-controlled process, confirmed by scan rate studies showing a linear relationship between peak current (Ip) and the square root of the scan rate (v1/2).
- Optimal Conditions: The highest peak current for OTB oxidation was achieved using 0.1 M H2SO4 as the supporting electrolyte (pH 0.3).
- High Precision: The BDDE exhibited excellent repeatability, with a Relative Standard Deviation (RSD%) for peak current measured at 0.62%.
- Electrode Comparison: OTB oxidation occurred at distinct potentials: approximately +1.00 V on GCE and +1.50 V on BDDE, highlighting the difference in electrode surface activity.
Technical Specifications
Section titled âTechnical SpecificationsâThe following parameters and performance metrics were determined under optimal conditions (0.1 M H2SO4) using the DPV technique.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Optimal Supporting Electrolyte | 0.1 M H2SO4 | M | pH 0.3 |
| OTB Oxidation Peak Potential (Ep) | 1.0222 | V | GCE |
| OTB Oxidation Peak Potential (Ep) | 1.5761 | V | BDDE |
| Limit of Detection (LOD) | 1.17x10-5 | M | GCE (DPV) |
| Limit of Detection (LOD) | 4.92x10-6 | M | BDDE (DPV) |
| Linearity Range (GCE) | 6x10-5 - 8x10-4 | M | DPV |
| Linearity Range (BDDE) | 8x10-5 - 8x10-4 | M | DPV |
| Repeatability (RSD%) | 0.86 | % | GCE (Peak Current) |
| Repeatability (RSD%) | 0.62 | % | BDDE (Peak Current) |
| Calculated Electron Transfer (n) | 2.40 | - | GCE (Based on Ep vs. log v slope) |
| Calculated Electron Transfer (n) | 1.25 | - | BDDE (Based on Ep vs. log v slope) |
| DPV Scan Rate (Optimal) | 0.010071 | mVs-1 | Used for calibration |
| CV Scan Rate (Mechanism Study) | 0.05 | Vs-1 | Used for pH and mechanism study |
Key Methodologies
Section titled âKey MethodologiesâThe electrochemical investigation utilized a standard three-electrode cell setup and specific pulse voltammetry parameters.
- Instrumentation: Measurements were conducted using an AUTOLAB 204 potentiostat/galvanostat controlled by NOVA 1.8 software.
- Electrode Setup: A typical 10 ml three-electrode cell was employed:
- Working Electrodes: Boron-Doped Diamond Electrode (BDDE) and Glassy Carbon Electrode (GCE).
- Counter Electrode: Platinum (Pt) wire.
- Reference Electrode: Ag/AgCl.
- Electrode Pretreatment: Before each measurement, the working electrode (BDDE or GCE) was manually polished on a smooth pad using slurries prepared from 0.01 M aluminum oxide, followed by thorough cleaning with double-distilled water.
- Electrolyte Screening: The electrochemical behavior was studied across a wide pH range (0.3-12.0) using various supporting electrolytes, including:
- 0.1 M and 0.5 M H2SO4 solutions.
- Phosphate buffers (pH 2.0-8.0).
- Acetate buffers (pH 3.7-5.7).
- Britton Robinson buffers (pH 2.0-12.0).
- Optimal DPV Parameters: The final analytical method used the following optimized DPV settings in 0.1 M H2SO4:
- Scan Rate: 0.010071 mVs-1
- Interval Time: 0.5 s
- Step Potential: 0.005 V
- Modulation Amplitude: 0.05 V
- Modulation Time: 0.05 s
- Mechanism Study: Cyclic Voltammetry (CV) was performed at various scan rates (0.01 to 1.00 Vs-1) and pH levels to confirm the irreversible, diffusion-controlled nature of the OTB electrooxidation.
Commercial Applications
Section titled âCommercial ApplicationsâThe use of BDDE in this study leverages its unique properties (wide potential window, low background current, and chemical stability) for high-performance sensing, relevant to several industrial sectors.
- Pharmaceutical Quality Control (QC): Provides a fast, accurate, and low-cost alternative to traditional HPLC and capillary electrophoresis methods for routine drug assay and quality control of Otilonium Bromide in tablet dosage forms.
- Electroanalytical Sensing: BDDE technology is critical for developing highly sensitive sensors for active pharmaceutical ingredients (APIs) and metabolites, especially in complex or aggressive media (like strong acids used here).
- High-Stability Electrodes: The corrosion resistance and extreme electrochemical stability of BDDE make it suitable for applications requiring long-term operation in harsh chemical environments.
- Environmental Monitoring: The principles of high-sensitivity DPV on BDDE can be extended to detect trace levels of organic pollutants or other chemical contaminants in water or industrial effluent.
- Biomedical Diagnostics: Development of rapid, selective electrochemical methods for drug monitoring in biological fluids, offering advantages over labor-intensive chromatographic techniques.
View Original Abstract
Objective: Using cyclic (CV) and differential pulse (DPV) voltammetric techniques, the electrochemical research of otilonium bromide (OTB) was carried out over a wide pH range (0.3-12) at glassy carbon electrodes (GCE) and boron-doped diamond electrodes (BDDE). The typical electrochemical behavior of OTB was identified as being dependent on the type of working electrode and pH. This research aims to provide a brand-new electroanalytical technique for measuring OTB in buffer solutions. Material and Method: All experiments employed the typical three-electrode cell of 10 ml capacity in conjunction with a platinum wire counter electrode, a BDDE and GCE working electrode, and an Ag/AgCl reference electrode. NOVA 1.8 software and an AUTOLAB 204 potentiostat/galvanostat were used for electrochemical measurements. Result and Discussion: The electrochemical behavior of OTB, which belongs to a class of drugs called âantispasmodicsâ (spasm and cramps reliever), primarily used to treat irritable bowel syndrome (IBS), and other gastrointestinal conditions characterized by motility problems, painful bowel spasms and distension (swelling and bloating in the belly area), was examined in 0.1 M H2SO4 at BDDE and GCE. The electrooxidation mechanism was also investigated by conducting CV investigations at various pH levels throughout a broad pH range (pH 0.3-12.0). Understanding the mechanism was aided by scan rate investigations, which revealed that diffusion was controlled for both electrodes. The proposed technique was successfully used to determine OTB under optimal conditions.