Voltammetric Determination of Diclofenac Sodium Using Tyrosine-Modified Carbon Paste Electrode

Functionalized fennel extract-mediated alumina/cerium oxide nanocomposite potentiometric sensor for the determination of diclofenac sodium medication

The current work suggests a new, ultrasensitive green functionalized sensor for the determination of anti-inflammatory medication diclofenac sodium (DCF). Alumina (Al2O3) and cerium oxide (CeO2) nanoparticles (NPs) have attracted great interest for their use as outstanding and electroactive nanocomposite in potentiometric and sensory research due to their ultrafunctional potential. The formed nanoparticles have been confirmed using various spectroscopic and microscopic techniques. The fennel extract-mediated Al2O3/CeO2 nanocomposite (Al2O3/CeO2 NCS) modified coated wire membrane sensor developed in this study was used to quantify DCF in bulk and commercial products. Diclofenac sodium was coupled with phosphomolybdic acid (PMA) to generate diclofenac phosphomolybdate (DCF-PM) as an active ion-pair in the existence of polyvinyl chloride (PVC) and o-nitrophenyl octyl ether (o-NPOE). Clear peaks at 270, and 303 nm with band gaps of 4.59 eV and 4.09 eV were measured using UV-vis spectroscopy of Al2O3 and CeO2, respectively. The crystallite sizes of the formed nanoparticles were XRD-determined to be 30.13 ± 8, 17.72 ± 3, and 35.8 ± 0.5 nm for Al2O3, CeO2, and Al2O3/CeO2 NCS, respectively. The developed sensor showed excellent response for the measurement and assay of DCF, with a linearity between 1.0 × 10-9 and 1.0 × 10-2 mol L-1. EmV = (57.76) log [DCF] +622.69 was derived. On the other hand, the typical type DCF-PM presented a potentiometric response range of 1.0 × 10-5-1.0 × 10-2 mol L-1 and a regression equation of EmV = (56.97) log [DCF]+367.16. The functionalized sensor that was proposed was successful in determining DCF in its commercial tablets with percent recovery 99.95 ± 0.3. Method validation has been used to improve the suitability of the suggested potentiometric technique, by studying various parameters with respect to the international council harmonization requirements for analytical methodologies.

Characterization of laccases from Trametes hirsuta in the context of bioremediation of wastewater treatment plant effluent

The bioremediation of pharmaceutical compounds contained in wastewater, in an ecological and sustainable way, is possible via the oxidative action of fungal laccases. The discovery of new fungal laccases with unique physico-chemical characteristics pushes researchers to identify suitable laccases for specific applications. The aim of this study is to purify and characterize laccase isoenzymes produced from the Trametes hirsuta IBB450 strain for the bioremediation of pharmaceutical compounds. Two main laccases mixtures were observed and purified in the extracts and were called Yn and Yg. Peptide fingerprinting analysis suggested that Yn was constituted mainly of laccase Q02497 and Yg of laccase A0A6M5CX58, respectively. Robustness tests, based on tolerance and stability, showed that both laccases were affected in a relatively similar way by salts (KCl, NaCl), organic solvents (ACN, MeOH), denaturing compounds (urea, trypsin, copper) and were virtually unaffected and stable in wastewater. Determination of kinetic constants (Michaelis (KM), catalytic constant (kcat) and kinetic efficiency (K=kcat/KM)) for the transformation of synthetic hormone 17α-ethynylestradiol and the anti-inflammatory agent diclofenac indicates a lower KM and kcat for laccase Yn but relative similar K constant compared to Yg. Synergistic effects were observed for the transformation of diclofenac, unlike 17α-ethynylestradiol. Transformation studies of 17α-ethynylestradiol at different temperatures (4 and 21 °C) indicate a transformation rate reduction of approximately 75-80% at 4 °C against 25% for diclofenac in less than an hour. Finally, the classification of laccases Yg and Yn into one of eight groups (group A-H) suggests that laccase Yg belongs to group A (constitutive laccase) and laccase Yn belongs to group B (inducible laccase).

Carrasco-Correa E, Varanasupakul P, Kubáň P, Miró M. Programmable Millifluidic Platform Integrating Automatic Electromembrane Extraction Cleanup and In-Line Electrochemical Detection: A Proof of Concept

A fully automatic millifluidic sensing platform coupling in-line nonsupported microelectromembrane extraction (μ-EME) with electrochemical detection (ECD) is herein proposed for the first time. Exploiting the features of the second generation of flow analysis, termed sequential injection (SI), the smart integration of SI and μ-EME-ECD enables (i) the repeatable formation of microvolumes of phases for the extraction step in a membrane-less (nonsupported) arrangement, (ii) diverting the acceptor plug to the ECD sensing device, (iii) in-line pH adjustment before the detection step, and (iv) washing of the platform for efficient removal of remnants of wetting film solvent, all entirely unsupervised. The real-life applicability of the miniaturized sensing system is studied for in-line sample cleanup and ECD of diclofenac as a model analyte after μ-EME of urine as a complex biological sample. A comprehensive study of the merits and the limitations of μ-EME solvents on ECD is presented. Under the optimal experimental conditions using 14 μL of unprocessed urine as the donor, 14 μL of 1-nonanol as the organic phase, and 14 μL of 25 mM NaOH as the acceptor in a 2.4 mm ID PTFE tubing, an extraction voltage of 250 V, and an extraction time of 10 min, an absolute (mass) extraction recovery of 48% of diclofenac in urine is obtained. The proposed flow-through system is proven to efficiently remove the interfering effect of predominantly occurring organic species in human urine on ECD with RSD% less than 8.6%.

Simultaneous Electrochemical Determination of Chlorzoxazone and Diclofenac on an Efficient Modified Glassy Carbon Electrode by Lanthanum Oxide@ Copper(I) Sulfide Composite

This study synthesized a La2O3@snowflake-like Cu2S composite to fabricate an electrochemical sensor for sensitively simultaneous detection of diclofenac and chlorzoxazone exploiting an easy hydrothermal approach, followed by analysis with XRD, FE-SEM, and EDX methods. According to voltammetric studies, the electrocatalytic diclofenac and chlorzoxazone oxidations on the electrode modified with La2O3@SF-L Cu2S composites were increased, with greater oxidation currents, as well as the oxidation potential was significantly decreased due to synergetic impact of La2O3@SF-L Cu2S composites when compared with the pure SF-L Cu2S NS-modified electrode. The differential pulse voltammetry findings showed wide straight lines (0.01–900.0 μM) for La2O3 NP@SF-L Cu2S NS-modified electrode with a limit of detection (LOD) of 1.7 and 2.3 nM for the detection of diclofenac and chlorzoxazone, respectively. In addition, the limit of quantification was calculated to be 5.7 and 7.6 nM for diclofenac and chlorzoxazone, respectively. The diffusion coefficient was calculated to be 1.16 × 10−5and 8.4 × 10−6 cm2/s for diclofenac and chlorzoxazone oxidation on the modified electrode, respectively. Our proposed electrode was examined for applicability by detecting diclofenac and chlorzoxazone in real specimens.

Micellar-Enhanced Spectrofluorimetric Method for Quantification of Diclofenac Potassium in Pure Form, in Pharmaceutical Preparations and Human Plasma

A rapid, simple and economical spectrofluorimetric method for the determination of diclofenac potassium in pure form, in pharmaceutical preparations and in human plasma has been developed. The method is based on the enhancement of the fluorescence signal of diclofenac potassium by the addition of sodium dodecyl sulphate in McIvaine buffer with a pH of 5. Different experimental conditions such as buffer type, pH, type and concentration of surfactants were investigated. The fluorescence intensity of the solution was recorded at 361 nm after excitation at 243 nm. The method shows linearity in the concentration range of 0.2 μg mL–1–10 μg mL–1 with a good correlation coefficient of 0.997. The relative standard deviation value was 3.62 (n = 7). The limit of detection and limit of quantification were calculated to be 2.84 × 10–3 μg mL–1 and 9.47 × 10–3 μg mL-1, respectively. The effect of excipients and co-administrated drugs was investigated and no interference was observed. The method was successfully applied for the determination of diclofenac potassium in pure form, in pharmaceutical products and in human plasma. The percentage recoveries obtained ranged from 100.25% to 102.16% for pure form and 97.50% to 102.00% for pharmaceutical products and from 98.50% to 101.67% for human plasma.

Design of an electrochemical platform for the determination of diclofenac sodium utilizing a graphenized pencil graphite electrode modified with a Cu–Al layered double hydroxide/chicken feet yellow membrane

A novel electrochemical sensor based on a Cu–Al layered double hydroxide (Cu–Al LDH)/chicken feet yellow membrane (CFYM) modified graphenized pencil graphite electrode (GPGE) was designed.

Nanomaterial-based electrochemical sensors and biosensors for the detection of pharmaceutical compounds

The surging growth of the pharmaceutical industry is a result of the rapidly increasing human population, which has inevitably led to new biomedical and environmental issues. Aside from the quality control of pharmaceutical production and drug delivery, there is an urgent need for precise, sensitive, portable, and cost-effective technologies to track patient overdosing and to monitor ambient water sources and wastewater for pharmaceutical pollutants. The development of advanced nanomaterial-based electrochemical sensors and biosensors for the detection of pharmaceutical compounds has garnered immense attention due to their advantages, such as high sensitivity and selectivity, real-time monitoring, and ease of use. This review article surveys state-of-the-art nanomaterials-based electrochemical sensors and biosensors for the detection and quantification of six classes of significant pharmaceutical compounds, including anti-inflammatory, anti-depressant, anti-bacterial, anti-viral, anti-fungal, and anti-cancer drugs. Important factors such as sensor/analyte interactions, design rationale, fabrication, characterization, sensitivity, and selectivity are discussed. Strategies for the development of high-performance electrochemical sensors and biosensors tailored toward specific pharmaceuticals are highlighted to provide readers and scientists with an extensive toolbox for the detection of a wide range of pharmaceuticals. Our aims are two-fold: (i) to inspire readers by further elucidating the properties and functionalities of existing nanomaterials for the detection of pharmaceuticals; and (ii) to provide examples of the potential opportunities that these devices have for the advanced sensing of pharmaceutical compounds toward safeguarding human health and ecosystems on a global scale.

First Electrochemical Sensor (Screen-Printed Carbon Electrode Modified with Carboxyl Functionalized Multiwalled Carbon Nanotubes) for Ultratrace Determination of Diclofenac

A simple, sensitive and time-saving differential-pulse adsorptive stripping voltammetric (DPAdSV) procedure using a screen-printed carbon electrode modified with carboxyl functionalized multiwalled carbon nanotubes (SPCE/MWCNTs-COOH) for the determination of diclofenac (DF) is presented. The sensor was characterized using optical profilometry, SEM, and cyclic voltammetry (CV). The use of carboxyl functionalized MWCNTs as a SPCE modifier improved the electron transfer process and the active surface area of sensor. Under optimum conditions, very sensitive results were obtained with a linear range of 0.1–10.0 nmol L⁻¹ and a limit of detection value of 0.028 nmol L⁻¹. The SPCE/MWCNTs-COOH also exhibited satisfactory repeatability, reproducibility, and selectivity towards potential interferences. Moreover, for the first time, the electrochemical sensor allows determining the real concentrations of DF in environmental water samples without sample pretreatment steps.

Electrochemical Behavior and Detection of Diclofenac at a Microporous Si3N4 Membrane Modified Water–1,6-dichlorohexane Interface System

The electrochemical behavior when the liquid–liquid interface was modified by commercially available, microporous silicon nitride membrane, was achieved using cyclic voltammetry with tetramethyl ammonium. The transfer characteristics of the ionizable drug diclofenac ( DCF − ), as an anti-inflammatory, anti-rheumatic, antipyretic, and analgesic treatment in common use in biomedical applications, were also investigated across microporous silicon nitride-modified liquid interface. Thus, some thermodynamic variables for DCF − , such as the standard Gibbs energy of transfer, the standard transfer potential and lipophilicity were estimated. Furthermore, the influence of possible interfering substances (ascorbic acid, sugar, amino acid, urea, and metal ions) on the detection of DCF − was investigated. An electrochemical DCF sensor is investigated using differential pulse voltammetry (DPV) as the quantification technique, a linear range of 8–56 µM and a limit of detection of 1.5 µM was possible due to the miniaturized interfaces formed within silicon nitride.

A Box-Behnken Optimized Methodology for the Quantification of Diclofenac using a Carbon Paste-Multiwalled Carbon Nanotubes Electrode

Background:

Diclofenac is a widely used nonsteroidal anti-inflammatory drug. Recent studies have shown that frequent consumption of this drug in high concentrations can cause heart diseases, so strict control of diclofenac’s quantity in commercial drugs is necessary. This paper presents the development of an optimized voltammetric methodology for the quantification of diclofenac, which offers some advantages over other electrochemical and accepted methods.

Objective:

Optimize with a Box-Behnken design the differential pulse voltammetry parameters towards the quantification of diclofenac in pharmaceutical samples.

Methods:

Diclofenac behavior in the working electrode was evaluated by cyclic voltammetry, in order to stablish the best conditions for diclofenac’s quantification. A Box-Behnken design was then used to optimize the differential pulse voltammetry parameters and stablish the analytical behavior of the proposed methodology. Commercial tablets were prepared for analysis according to the Pharmacopeia, the DPV optimized methodology was used to quantify diclofenac in the samples, and the results were statistically compared with those obtained with the official methodology.

Results:

After optimization, the analytical parameters found were: correlation coefficient of 0.998, detection limit of 0.001 µM, quantification limit of 0.0033 µM and sensitivity of 0.299 µA.µM-1. The statistical analysis showed there were no significant differences between the results obtained with the proposed methodology and those obtained with the official methodology.

Conclusion:

The statistical analysis showed that the proposed methodology is as reliable as the official spectrophotometric one for the quantification of diclofenac in commercial drugs, with very competitive analytical parameters, and even better to others found with more complex electrodes.

A new diclofenac molecularly imprinted electrochemical sensor based upon a polyaniline/reduced graphene oxide nano-composite

A diclofenac (DCF)-imprinted polymer, composed of polyaniline, reduced graphene oxide (rGO) and triphenylamine, as cross linker, was synthetized. This composite was identified by using SEM and FT-IR techniques. The prepared DCF-imprinted polymer (MIP) was used for modification of carbon paste electrodes (CPEs) to fabricate a selective DCF electrochemical sensor. Electrochemical behavior of DCF on the investigated sensor and the optimization of the parameters affecting the DCF determination were screened by cyclic voltammetry (CV). The cyclic voltammogram of DCF showed an anodic peak current at about 0.5 V (vs. SCE). The calibration curve for DCF determination was obtained by applying the investigated sensor as working electrode in differential pulse voltammetry (DPV). A linear increase in the anodic peak current was observed in the range 5-80 mg L^-1 of DCF. The corresponding limit of detection was calculated to be 1.1 mg L^-1. The relative standard deviations of the inter- and intra-day analysis of DCF presented by the method were found to be as 2.43% and 2.47%, respectively. The selectivity of the investigated sensor was evaluated by its use for determination of DCF in the binary solutions containing DCF/glucose, DCF/urea and DCF/ascorbic acid. It was shown that the fabricated electrode can be successfully used for analysis of DCF in pharmaceutical and urine samples.

Taking advantage of CTAB micelles for the simultaneous electrochemical quantification of diclofenac and acetaminophen in aqueous media

Cetyltrimethylammonium bromide hemimicelles, formed on the surfaces of a carbon paste electrode, selectively adsorbed diclofenac molecules from a neutral aqueous solution containing acetaminophen, allowing simultaneous quantification of both drugs.

Manipulating ratio spectra for the spectrophotometric analysis of diclofenac sodium and pantoprazole sodium in laboratory mixtures and tablet formulation

Objective. Three sensitive, selective, and precise spectrophotometric methods based on manipulation of ratio spectra, have been developed and validated for the determination of diclofenac sodium and pantoprazole sodium. Materials and Methods. The first method is based on ratio spectra peak to peak measurement using the amplitudes at 251 and 318 nm; the second method involves the first derivative of the ratio spectra (Δλ = 4 nm) using the peak amplitudes at 326.0 nm for diclofenac sodium and 337.0 nm for pantoprazole sodium. The third is the method of mean centering of ratio spectra using the values at 318.0 nm for both the analytes. Results. All the three methods were linear over the concentration range of 2.0–24.0 μg/mL for diclofenac sodium and 2.0–20.0 μg/mL for pantoprazole sodium. The methods were validated according to the ICH guidelines and accuracy, precision, repeatability, and robustness are found to be within the acceptable limit. The results of single factor ANOVA analysis indicated that there is no significant difference among the developed methods. Conclusions. The developed methods provided simple resolution of this binary combination from laboratory mixtures and pharmaceutical preparations and can be conveniently adopted for routine quality control analysis.