Fast and simple voltammetric sensing of avanafil in the pharmaceutical formulation by using unmodified boron-doped diamond electrode
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-06-27 |
| Journal | ADMET & DMPK |
| Authors | Hoshyar Saadi Ali, Hemn A.H. Barzani, Yavuz Yardım |
| Institutions | Van YĂŒzĂŒncĂŒ Yıl Ăniversitesi, Lebanese French University |
| Citations | 5 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research details the development of a fast, simple, and highly sensitive voltammetric method for quantifying avanafil (AVN) using an unmodified Boron-Doped Diamond (BDD) electrode.
- Core Value Proposition: The method eliminates the need for complex electrode modification, significantly simplifying the analytical process, reducing resource consumption, and enhancing feasibility compared to previous electrochemical studies.
- Material and Technique: Unmodified BDD (1000 ppm B doping) was used as the working electrode, employing Square-Wave Voltammetry (SWV) for quantification.
- Optimal Conditions: Analysis was performed in Britton-Robinson (BR) buffer (0.04 mol L-1) at pH 4.0, yielding a sharp, irreversible anodic peak at +1.33 V (vs. Ag/AgCl).
- High Sensitivity: The method achieved a wide linear dynamic range of 1.0 to 62 ”mol L-1 and a low Limit of Detection (LOD) of 0.29 ”mol L-1.
- Robustness and Precision: The method demonstrated good reproducibility with intra-day and inter-day Relative Standard Deviations (RSDs) of 5.6% and 7.2%, respectively.
- Practical Application: Successful determination of AVN content in commercial pharmaceutical tablets (103.2 mg found vs. 100.0 mg labeled) and satisfactory recovery rates in spiked human urine samples (92.0% ± 4.3%).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Electrode Material | Boron-Doped Diamond (BDD) | N/A | Working electrode |
| Boron Doping Level | 1000 | ppm | BDD specification |
| Electrode Diameter | 3 | mm | BDD specification |
| Electroactive Surface Area | 0.036 | cm2 | Determined via prior study |
| Reference Electrode | Ag/AgCl (3 mol L-1 NaCl) | N/A | BAS Model RE-1 |
| Optimal Electrolyte | Britton-Robinson Buffer (BR) | 0.04 mol L-1 | pH 4.0 |
| Optimal Peak Potential (Ep) | +1.33 | V | SWV vs. Ag/AgCl |
| SWV Frequency (f) | 50 | Hz | Optimized parameter |
| SWV Step Potential (ÎEs) | 12 | mV | Optimized parameter |
| SWV Pulse Amplitude (ÎEsw) | 60 | mV | Optimized parameter |
| Linear Dynamic Range (LDR) | 1.0 to 62 | ”mol L-1 | AVN concentration |
| Limit of Detection (LOD) | 0.29 | ”mol L-1 | Calculated via 3s/m approach |
| Oxidation Mechanism | Irreversible Anodic | N/A | Involves 1 electron and 1 proton |
| Intra-day Precision (RSD) | 5.6 | % | Repeatability (0.5 ”g mL-1 AVN) |
| Inter-day Precision (RSD) | 7.2 | % | Reproducibility (5 consecutive days) |
| Tablet Recovery | 103.2 | mg | Found vs. 100.0 mg labeled (RSD 3.8%) |
Key Methodologies
Section titled âKey MethodologiesâThe experimental approach utilized cyclic voltammetry (CV) for mechanistic study and square-wave voltammetry (SWV) for quantification, focusing on optimizing parameters for the unmodified BDD electrode.
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Electrode Pretreatment:
- The BDD electrode surface was activated daily using Anodic (APT) and Cathodic (CPT) pretreatment in 0.5 mol L-1 H2SO4.
- Applied voltage range: +1.8 V to -1.8 V.
- Cleaning Protocol: Gentle rubbing with a moist BAS polishing pad, followed by rinsing with deionized water to remove residual oxidation byproducts.
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Mechanistic Study (CV):
- CV was performed in 0.04 mol L-1 BR buffer (pH 4.0) over a range of 0 to 1.70 V.
- The oxidation was confirmed as irreversible (no cathodic peak on reverse scan).
- Scan rate dependence analysis confirmed the process is influenced by both adsorption and diffusion effects (log Ip vs. log v slope â 0.553).
- The reaction mechanism was determined to involve a 1-electron, 1-proton transfer (n â 1.24, based on Ep-Ep/2 analysis).
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Optimization (SWV):
- The supporting electrolyte and pH were optimized, confirming 0.04 mol L-1 BR buffer at pH 4.0 provided the highest, sharpest peak current.
- Instrumental parameters were optimized: frequency (50 Hz), step potential (12 mV), and pulse amplitude (60 mV).
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Sample Analysis:
- Pharmaceuticals: Tablets were ground, dissolved in 0.1 mol L-1 HCl, and analyzed using the standard addition method in the optimized BR buffer.
- Biological Fluids: Urine samples were spiked with AVN standard solution, diluted with BR buffer (pH 4.0), and analyzed directly using the standard addition method.
Commercial Applications
Section titled âCommercial ApplicationsâThe use of unmodified Boron-Doped Diamond (BDD) electrodes for sensitive drug detection is highly relevant to industries requiring robust, stable, and chemically inert sensors.
- Pharmaceutical Quality Control (QC): Direct, fast, and cost-effective quantification of active pharmaceutical ingredients (AVN) in fixed-dose formulations, providing an alternative to complex HPLC or UV-Vis methods.
- Clinical and Forensic Diagnostics: Direct determination of drug concentrations (AVN) in biological fluids (like urine or plasma) without extensive sample preparation (extraction or filtration), leveraging BDDâs resistance to fouling by biological matrices (e.g., uric acid, dopamine).
- Electrochemical Sensing and Manufacturing: BDD electrodes are ideal for industrial environments due to their wide electrochemical potential window, chemical inertness, and mechanical durability, making them suitable for continuous monitoring systems.
- Drug Metabolism and Pharmacokinetics (DMPK) Studies: The high sensitivity and low LOD achieved allow for monitoring low concentrations of drugs or metabolites in research settings.
View Original Abstract
Background and purpose: Erectile dysfunction is a common issue among adult males involving difficulty in maintaining an erection, and it is often treated with fast-acting, low-side-effect drugs like avanafil (AVN), among other phosphodiesterase-5 inhibitors. Hence, developing fast, simple, and sensitive methods to detect AVN is crucial. Experimental approach: This study conducts an electroanalytical inquiry and provides a new voltammetric method for accurately analyzing AVN utilizing a boron-doped diamond (BDD) electrode without any modifications. Key results: In the Britton-Robinson buffer (BR, 0.04 mol L-1, pH 4.0), cyclic voltamÂmetry showed a clearly defined and irreversible anodic peak at around +1.44 V relative to Ag/AgCl. The pH of the solution was shown to have an impact on the voltammetric signals of the oxidation peaks. A good linear response for AVN quantification was achieved using square-wave voltammetry. This was done in a 0.04 mol L-1 BR (pH 4.0) solution at a potential of +1.33 V (vs. Ag/AgCl). The method exhibited a wide dynamic range of 0.5 to 30.0 ÎŒg mL-1 (1.0 to 62 ”mol L-1) and a low limit of detection of 0.14 ÎŒg mL-1 (0.29 ”mol L-1). The method proposed demonstrated suitability for determining AVN content in pharmaceutical formulations. The accuracy of the approach was demonstrated by comparing the results obtained using the developed method with those achieved using the UV-Vis spectrometry method. Conclusion: Our method simplifies the analytical process by eliminating the need for electrode modification, reducing both time and resource requirements while enhancing overall feasibility.