Tablet Samples Research Articles

Polystyrene:β-Cyclodextrin Inclusion Complex-Supported Y2O3-Based Electrochemical Sensor: Effective and Simultaneous Determination of 4-Aminoantipyrine and Acyclovir Drugs

In this study, a novel polystyrene:β-cyclodextrin inclusion complex-supported yttrium oxide (Y2O3)-modified glassy carbon electrode (PS:β-CD IC/Y2O3/GCE) was developed for the simultaneous determination of selected drugs, 4-aminoantipyrine (4-AAP) and acyclovir (ACV) for the first time. The results showed that PS:β-CD IC/Y2O3/GCE exhibits well-defined oxidation peak currents with a lower positive shift in peak potential in the simultaneous determination of 4-AAP and ACV compared to the bare GCE, demonstrating the superior catalytic activity. The fabricated sensor showed the linear ranges of 0.01–655 and 0.01–918 μM with low detection limits of 0.01 and 0.02 μM for the determination of 4-AAP and ACV, respectively. Further, the as-prepared PS:β-CD IC/Y2O3/GCE has been applied to the simultaneous and individual determination of 4-AAP and ACV in human urine and commercial ACV tablet samples with satisfactory recovery (98–99.3 and 88–96.6%), thereby showing a notable potential for extensive applications in the...

A novel and sensitive fluorescent assay for artemisinin with graphene quantum dots based on inner filter effect

The authors describe a novel method for the determination of artemisinin (ART) by using graphene quantum dots (GQDs) as the fluorescent probes. This method is based on the fact that ART can react with p-aminophenylboronic acid (p-ABA) to produce p-aminophenol (p-AP). While in the presence of tyrosinase (TYR), p-AP can be oxidized into 4-amino-1,2-benzoquinone, which effectively quenched the fluorescence of GQDs due to the inner filter effect (IFE). By making use of these reactions, a novel and sensitive fluorescent assay for ART has been developed. The calibration curve for the determination of ART is linear in the range of 0.1–5 μM and 5–55 μM with the detection limit of 33 nM, which is more sensitive than most of other methods. Some common coexisting substances including Ca2+, Na+, Mg2+, K+, PO43-, starch, lactose, dextrin, and magnesium stearat have negligible effects on the fluorescence intensity of GQDs-TYR-p-ABA system. Finally, the sensing system was successfully applied to the detection of the compound naphthoquine phosphate tablet samples with satisfactory recoveries. This IFE-based GQDs fluorescence sensing strategy is facile and sensitive for the determination of ART because neither the surface modification nor the linking between the receptor and the fluorophore is required.

New Voltammetric Approach to the Quantitation of Paracetamol in Tablets and Syrup using Chemometric Optimization Technique

A new voltammetric approach was developed for the determination of paracetamol in tablet and syrup samples using chemometric optimization. The method is based on the use of the gold nanoparticles–polyaniline (AuNPs−PA) modified pencil graphite electrode (PGE). Electrode system was fabricated by using the electrochemical reduction of gold on aniline modified pencil electrode to give gold nanoparticles. A 33 full factorial design was used to find optimal oxidation conditions of paracetamol on the AuNPs−PA−PGE. The optimal oxidation conditions of drug substance were found as –524 mV for the accumulation potential, 295 s for the accumulation time and pH 8.69 (for the phosphate buffer solution, 0.1 M). The determination of paracetamol was linear in the range of 2.0 × 10–7–6.0 × 10–6 M with a detection limit of 5 × 10–8 M. As a result, the proposed voltammetric approach gave satisfactory results for the determination of the related drug substance in tablets and syrup.

Electrochemical Determination of Mycophenolate Mofetil in Drug Samples Using Carbon Paste Electrode Modified with 1-methyl-3-butylimidazolium Bromide and NiO/SWCNTs Nanocomposite

Background:The mycophenolate mofetil is an immunosuppressant drug with wide application in the treatment of cancer and prevent rejection in organ transplantation. This drug showed many sides effects for pregnant women and determination of this drug is very important in the human body.Objective:A new electrochemical strategy was described for analysis of Mycophenolate Mofetil (MMF) using novel voltammetric sensor. The sensor was fabricated using NiO/SWCNTs and 1-methyl- 3-butylimidazolium bromide as two conductive mediators for modification of carbon paste electrode (NiO/SWCNTs/MBBr/CPE). The NiO/SWCNTs/MBBr/CPE can be used for analysis of MMF in aqueous buffer solution in the concentration range of 0.08-900 µM. In addition, the NiO/SWCNTs/ MBBr/CPE reduced oxidation over-potential of MMF ~ 80 mV and increased the oxidation current of MMF ~ 2.85 times. In the final step, NiO/SWCNTs/MBBr/CPE was used for determination of MMF in pharmaceutical serum and tablet samples.

Cathodic “signal-on” photoelectrochemical aptasensor for chloramphenicol detection using hierarchical porous flower-like Bi-BiOI@C composite

A novel p-type semiconductor-based cathodic “signal-on” photoelectrochemical (PEC) aptasensor was proposed for highly sensitive and selective detection of chloramphenicol (CAP). The photocathode was fabricated with hierarchical porous flower-like Bi-BiOI@C composite synthesized via a one-pot solvothermal method using glucose as both green reductant and carbon precursor. Due to the surface plasmon resonance (SPR) effect of Bi and high-conductivity of carbon, the composite exhibited an enhanced cathodic photocurrent as compared with pure BiOI or Bi-BiOI. When CAP-binding aptamer was immobilized as recognition element on Bi-BiOI@C modified electrode, a cathodic PEC aptasensor showing specific “signal-on” response to CAP was constructed. Some influencing factors such as coating amount of Bi-BiOI@C suspension, applied bias potential, and aptamer concentration were studied. Under the optimum conditions, the cathodic photocurrent of the constructed PEC aptasensor increased linearly with CAP concentration from 2 to 250 nM, with a detection limit (3S/N) of 0.79 nΜ. The proposed sensor was successfully applied to the determination of CAP in pharmaceutical tablet, eye drop and lake water samples.

SIMULTANEOUS DETERMINATION OF DIPHENHYDRAMINE, EPHEDRINE, NOSCAPINE, AND GLYCEROL GLYCOLATE USING STABILITY-INDICATING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY: APPLICATION TO NOSCOF TABLETS

Objective: Noscof tablet is a fixed dosage combination formulation having diphenhydramine (DH), ephedrine (ED), noscapine (NP), and glycerol glycolate (GG). A sensitive, selective, accurate, precise, and stability-indicating reversed-phase high-performance liquid chromatography (RP-HPLC) method with photodiode array detection has been developed and validated for simultaneous analysis of DH, ED, NP, and GG in bulk drug and Noscof tablets.
 Methods: Reversed-phase chromatographic separation and analysis of DH, ED, NP, and GG were done on an Altima C18 column with 0.01 M KH2PO4 buffer (pH 3.5) and acetonitrile (50:50%, v/v) as mobile phase at 0.8 ml/min flow rate in isocratic mode. Detection was performed at 260 nm. The method was validated in harmony with International Conference on Harmonization (ICH) guidelines. The tablet sample solution was subjected to diverse stress conditions using ICH strategy such as hydrolytic degradation (neutral - with distilled water, alkaline - with 2 N NaOH, and acidic - with 2 N HCl), oxidation (with 10% H2O2), photodegradation (exposing to UV light), and dry heat degradation (exposing to 105°C).
 Results: Using the above stated chromatographic conditions, sharp peaks were obtained for ED, NP, DH, and GG with retention time of 3.272 min, 4.098 min, 5.467 min, and 6.783 min, respectively. Good regression coefficient values were obtained in the range of 2–12 μg/ml for ED, 3.75–22.5 μg/ml for NP, 3.125–18.75 μg/ml for DH, and 25–150 μg/ml for GG. The quantification limits were 0.181 μg/ml, 0.187 μg/ml, 0.246 μg/ml, and 1.114 μg/ml for ED, NP, DH, and GG, respectively. The values of validation parameters are within the acceptance limits given by ICH. The ED, NP, DH, and GG showed more percent of degradation in acid condition and less percent of degradation in the neutral condition. The peaks of degradants did not interfere with the peaks of analytes. ED, NP, DH, and GG were assessed with a good percentage of the assay (near to 100%) and low percent relative standard deviation (<2%) in Noscof tablets using the proposed method.
 Conclusion: The stability indicating RP-HPLC method developed was suitable for quantifying ED, NP, DH, and GG simultaneously in bulk as well as in tablet formulation.

Graphite/SiO2 film electrode modified with hybrid organic-inorganic perovskites: Synthesis, optical, electrochemical properties and application in electrochemical sensing of losartan

Hybrid organic-inorganic semiconductors (HOIS) still remain as research focus due to their exceptional optoelectronics properties, placing them as ideal candidates for use in the field of light emitting diodes and photovoltaics. In the present work, HOIS have been synthesized, characterized as well as adsorbed onto graphite/silica film electrodes (GSiHE), the latter used as simple, low cost, yet sensitive, electrochemical sensors. These composite electrodes have been specifically characterized with electrochemical methods and have been applied in the development of prototype electrochemical drug sensors; a paradigm is provided for simple, efficient, sensitive and relatively specific sensing of an antihypertensive drug, losartan (LOS). The electrochemical behavior of GSiHE film modified with HOIS was examined by cyclic voltammetry, while its morphology, structural and spectroscopic properties were investigated by field emission scanning electron microscopy, X-ray diffraction, porosimetry, optical and luminescence spectroscopies. Under optimized conditions, the modified film electrode demonstrated excellent electrocatalytic activity towards oxidation of LOS in the linear response range for concentrations from 4 × 10−5 M to 3.2 × 10−4 M (correlation coefficient 0.989) with the limit of detection computed at 3 × 10−6 M. The sensor takes advantage of the ability of ions to interact with the HOIS lattice on the GSiHE film; this type of sensor has demonstrated good repeatability, reproducibility and stability and was found to be applicable for use in determining pharmaceutical tablet sample concentrations.

Molecularly Imprinted Stir Bar Sorptive Extraction Coupled with High‑Performance Liquid Chromatography for Trace Analysis of Diclofenac in Different Real Samples

A novel molecularly imprinted polymer-coated stir bar has been used to selectively extract diclofenac (DFC) directly from real samples. DFC was used as template molecule for preparation of MIP coating. The effect of different parameters on the extraction efficiency were studied and the optimum conditions were established as: the absorption and desorption times were fixed at 10 min, stirring speed was 600 rpm, pH was adjusted to 5.1, the amount of NaCl was 0.35 mol/L and extraction process was performed at a temperature of 45 °C. Under the optimum conditions, the linear range of method was 0.5- 500.0 µg/L for DFC and the detection limit was calculated to be 0.15 µg/L with an enrichment factor of 242 folds. The technique was successfully applied for the analysis of trace amounts of DFC in seawater and commercial tablet samples. The mean recoveries of spiking real samples with DFC at 10.0 µg/L level were between 94.2-100.0 % with a mean RSD of 0.7-4.6%.

The In-vitro studies and evaluation of telmisartan marketed tablets

Tablets or capsules taken orally remain one of the most effective means of treatment available. The effectiveness of such dosage forms relies on the drug dissolving in the fluids of the gastrointestinal tract prior to absorption into the systemic circulation. The present study reveals the evaluation of four marketed sample of Telmisartan tablets. The main aim of the study is to conduct dissolution test on the tablets to determine the compliance with a given official monograph. Four different marketed samples of Telmisartan were purchased from local market. The Telmisartan tablets were evaluated for the various in-vitro tablet properties such as thickness, hardness, friability, weight variation, drug content, disintegration time and dissolution rate. In-vitro dissolution test is conducted on four different brands of telmisartan tablets to assess their equivalency. All the four marketed samples of Telmisartan have shown good tablet properties and comply with the pharmacopoeial specification. The in- vitro dissolution showed the 80% drug release within one hour from all the four brands which complies with the specification of pharmacopoeia.

İlaç Formülasyonundaki Asetilsalisilik Asit, Parasetamol ve Kafeinin Kemometrik Metotlarla Tayini

In this study, the results of ultraviolet spectrophotometry of paracetamol, acetylsalicylic acid and caffeine active substances in tablet drug sample were evaluated together with chemometric methods. In the experimental study, the synthetic mixtures were prepared by taking each drug from the active ingredient after obtaining the individual pure spectra of the substances. At the next stage, a tablet sample analysis was performed. From the chemometric methods, the principle component regression method (PCR) and the partial least squares method (PLS) have been successfully applied in the quantification of the synthetic mixtures and the tablet sample. When the data obtained are statistically analyzed, both the calculated recovery values ​​are high and the standard deviations are small enough. In addition, F-test was applied in terms of the suitability of the method and the results were found to be compatible. The results obtained with the help of applied chemometric methods are very fast, simple and reliable results.

Screen printed carbon electrode modified with magnetic core shell manganese ferrite nanoparticles for electrochemical detection of amlodipine

In the present work, a rapid and sensitive detection of the amlodipine (AML) based on the modified screen printed carbon electrode (SPCE) is developed. At first, SPCE was modified with magnetic core shell manganese ferrite nanoparticles (MCSNP). Cyclic voltammetry (CV) was used to study the electrochemical behaviour of AML and its determination was conducted by applying differential pulse voltammetry (DPV). The results were showed that, the modified SPCE in comparison with unmodified SPCE exhibited the enhanced electrocatalytic activity toward the oxidation of AML. A single irreversible oxidation peak was observed at a potentials of 600 and 725 mV (on the scale of Ag/AgCl electrode) on the modified SPCE and unmodified SPCE, respectively. Under the optimized conditions, the anodic peak current of AML recorded by DPV varies linearly with AML concentration in the range 0.5?400 ?M with a detection limit of 0.1 ?M. The modified SPCE was used for the quantitative analysis of AML in AML tablet and urine samples and the results indicated the feasibility of the developed method for AML analysis in routine detection.

Nanosilica modified sensor for the electro-oxidation and determination of an antihistamine drug

Abstract Electro-oxidation and determination of an antihistamine drug was carried out to study its electrochemical behavior by constructing a new sensor using silica nanoparticles. The response towards cetirizine oxidation process was excellent with good conductivity in the transfer of the electrons involved in the oxidation process. The homogeneous mixture of silica nanoparticles and graphite powder exhibits good response time, stability, sensitivity and reproducibility. A significant increase in the oxidation peak current was observed in phosphate buffer solution (PBS). Effect of accumulation time, scan rate, pH, concentration, excipients, and metal ions on the voltammetric behavior of the drug was studied by various voltammetric techniques. The catalytic properties of nanosilica particles reveal an increase in the peak current with less negative value of the potential. The relationship between scan rate and peak potential direct to calculate number of electrons and protons involved in the electro-oxidation process. A linear plot was obtained by varying the concentrations of the cetirizine. A low detection limit value and good recovery values shows us an applicability of the proposed electrode for tablet and urine samples analysis.

Nano level detection and analysis of an antiviral drug at ZnO nanoparticles modified sensor

Abstract An anti-viral drug, acyclovir (ACV) nanolevel detection and determination has been carried out using zinc oxide (ZnO) nanoparticles modified glassy carbon electrode. The construction of sensor involves fabrication of the working electrode with nanoparticles suspension. Due to increase in the surface area the peak current enhanced greatly. The ZnO nanoparticles showed good conductivity, stability, sensitivity towards electro-oxidation of ACV in all the pH range studied 3.0 -11.2 phosphate buffer solutions (PBS). The relationship between scan rate and peak potential with correlation coefficient was used to calculate number of electrons and protons involved in the electro-oxidation process. A linear plot was obtained by varying the concentrations of ACV. A probable reaction mechanism was also proposed. The limit of detection, quantification, heterogeneous rate constant values was calculated. A low detection limit value and good recovery values shows us an applicability of the proposed electrode for tablet and urine samples analysis.

Ultrasonication-assisted synthesis of sphere-like strontium cerate nanoparticles (SrCeO3 NPs) for the selective electrochemical detection of calcium channel antagonists nifedipine

In this work, strontium cerate nanoparticles (SrCeO3 NPs, SC NPs) were developed through facile synthetic techniques (Ultrasound-Assisted (UA) and Stirring-Assisted (SA) synthesis) and utilized as an electrocatalyst for the selective and sensitive electrochemical detection of calcium channel blocker nifedipine (NDF). The as-prepared UASC NPs and SASC NPs were characterized using XRD, Raman, TEM, EDS, mapping, XPS and BET analysis which exposed the formation of SC NPs in the form of spherical in shape and well crystalline in nature. BET studies reveal that UASC NPs have maximum surface area than that of SASC NPs. Further, the use of the as-developed UASC NPs and SASC NPs as an electrocatalyst for the detection of NDF. Interestingly, the UASC NPs modified screen printed carbon electrode (UASC NPs/SPCE) exhibited an excellent electrocatalytic activity in terms of lower reduction potential and enhanced reduction peak current when compared to SASC NPs and unmodified SPCE. Moreover, as-prepared UASC NPs/SPCE displayed wide linear response range (LR, 0.02–174 µM), lower detection limit (LOD, 5 nM) and good sensitivity (1.31 µA µM−1 cm−2) than that of SASC NPs (LR = 0.02–157 µM, LOD = 6.4 nM, sensitivity – 1.27 µA µM−1cm−2). Furthermore, UASC NPs/SPCE showed an excellent selectivity even in the existence of potentially co-interfering compounds such as similar functional group containing drugs, pollutants, biological substances and some common cations/anions. The developed sensor was successfully employed for the determination of NDF in real lake water, commercial NDF tablet and urine samples with acceptable recovery.

Simple, rapid, and sensitive electrochemical determination of antithyroid drug methimazole using a boron-doped diamond electrode

This paper aims a rapid, cheap, simple and modification-free electroanalytical methodology using a boron-doped diamond electrode pretreated anodically for the determination of antithyroid drug methimazole in pharmaceutical samples. The drug was irreversibly oxidized which was a diffusion-controlled process. Using square wave voltammetry, a linear response was obtained for methimazole determination in Britton–Robinson buffer (pH 5.0) at + 0.89 V (vs. Ag/AgCl). Linearity was found between the oxidation peak currents and the concentration of methimazole from 0.5 to 25.0 µg mL−1 (4.38 × 10−6–2.19 × 10−4 M) with a detection limit of 0.085 µg mL−1 (7.45 × 10−7 M). The proposed method was applied for the determination of methimazole in commercial tablet samples.

Molecularly imprinted based solid phase microextraction method for monitoring valproic acid in human serum and pharmaceutical formulations

In this paper, a straightforward method is presented to detect valproic acid after its microextraction. Molecularly imprinted polymer fiber was used in conjunction with chromatography-flame ionization to achieve this goal. A narrow bore silica capillary was adopted as a mold, via the copolymerization of meth acrylic acid–ethylene glycol dimethacrylate imprinted with VPA, to synthesize the fiber. Extraction temperature, extraction time, salt addition, pH, stirring rate, and desorption temperature—all of which are factors that can influence the extraction process—were measured, and adjusted accordingly. Linearity, precision, and detection limits, as analytical elements, were also evaluated under optimum conditions. Readings showed a linear range of 0.03–100 µg L− 1 (r2 = 0.998), and the limit of detection was measured as 0.01 µg L− 1. The established method was then applied in selective detection of valproic acid in tablet, syrup and human serum samples successfully.

A novel electrochemical nanosensor based on NH2-functionalized multi walled carbon nanotubes for the determination of catechol-orto-methyltransferase inhibitor entacapone

In this study, an antiparkinson drug Entacapone (ENP) is electrochemically investigated under optimized conditions using NH2 functionalized multi walled carbon nanotubes (NH2fMWCNT) decorated over glassy carbon electrode (GCE). The surface morphology of the NH2fMWCNT/GCE was probed by scanning electron microscopy (SEM) armed with EDX analysis. Electrochemical impedance spectroscopy (EIS) was employed to investigate the electron transfer capability of modified and bare electrodes. Cyclic voltammetry was used to compare the redox response of ENP on the surface of modified and unmodified electrodes. The influence of interfering agents was also studied to examine the selectivity of the designed sensor. For the purpose of practical applicability of the proposed method, differential pulse voltammetric method was applied for the investigation of ENP in real samples i.e., tablet, human serum and urine. Almost 100% recovery percentages were obtained from tablet, serum and urine samples with RSD% values of less than 2% for all the samples, thus, suggesting promising applicability of the designed electrochemical sensing platform (NH2fMWCNT/GCE) for determination of ENP in pharmaceutical dosage and real samples.

Label-free detection of folic acid using a sensitive fluorescent probe based on ovalbumin stabilized copper nanoclusters

In this work, ovalbumin (OVA) stabilized copper nanoclusters (OVA-Cu NCs) were prepared through a simple protein-stabilized synthetic method and applied for the sensitive determination of FA. Cu2+ ions were directly reduced to Cu (0) by a mild reducing agent, N2H4·H2O, at room temperature without any other complicated procedure such as adjusting pH and controlling the temperature of the reaction mixture. The as-prepared OVA-Cu NCs showed good chemical stability, wonderful water solubility and excellent biocompatibility. The OVA-Cu NCs were obtained with an average particle size of 2.0 nm and good dispersibility in aqueous solution. They also showed strong red emitting at 625 nm with a quantum yield of 3.95%. The OVA-Cu NCs were then applied for label-free detection of FA based on a static quenching mechanism. The linear calibration curve of detecting FA served from 0.5 μM − 200 μM with a detection limit of 0.18 μM. In addition, the developed method was also successfully applied to determine the content of FA in tablet, spinach, orange juice and biological samples with quantitative spike recoveries from 96.9% to 100.9%. For these reasons, the developed OVA-Cu NCs-based fluorescent strategy can thus offer a convenient label-free biosensor platform for the detection of FA in biomedical applications.

Electrochemical determination of epinephrine, uric acid and folic acid using a carbon paste electrode modified with novel ferrocene derivative and core–shell magnetic nanoparticles

The purpose of the current research was to construct an intermediate (2-(4-Ferrocenyl-[1,2,3]triazol-1-yl)-1-(naphthalen-2-yl) ethanone (2FTNE)) and a magnetic core–shell manganese ferrite nanoparticle (CMNP) to synthesis a modified carbon paste electrode (CPE). The electrochemical behavior of epinephrine (EP) was assessed by cyclic voltammetry and measured by square wave voltammetry by exposing to uric acid (UA) and folic acid (FA). High electrocatalytic activity for EP oxidation was seen in the 2FTNECMNP-modified CPE (2FTNEMCNPPE) compared to only CPE- and MCNP-modified CPE. The oxidation peak current of EP was linear within the range of 0.05–60 μM and its correlation coefficient was 0.999. The limit of detection was calculated at 0.016 μM for EP based on three times the standard deviation (3Sb) of the blank. According to the results, high selectivity, proper stability and good reproducibility was observed for the 2FTNEMCNPPE that detected EP, UA and FA successfully in an EP ampule, a folic acid tablet and urine samples, introducing 2FTNEMCNPPE with high capacity to develop the electrochemical sensors.

In-line monitoring of Ibuprofen during and after tablet compression using near-infrared spectroscopy

Near infrared spectroscopy (NIRS) used as process analytical technology tool to monitor Active Pharmaceutical Ingredient concentrations during tablet manufacturing has been reported to enhance overall product quality assurance. NIRS applications in different manufacturing stages are facilitated by their ability to handle different sample presentations – be it solids, liquids, gels or powders. The present study evaluates NIRS suitability for monitoring Ibuprofen concentrations (coated pellets form) inside the feed frame of a tableting press as well as in output tablets. Process monitoring was undertaken with quantitative chemometric analysis. NIRS-based predictions of concentrations both inside the feed frame and in tablets were compared to ultraviolet (UV) spectroscopy assays of temporally stratified tablet samples. Process dynamics were also compared in terms of concurrent concentrations change kinetics in the feed frame and in output tablets.NIRS showed good sensitivity to Ibuprofen concentrations despite the use of coated pellets. Ibuprofen contents as low as 1.7% w/w were detected effectively. NIRS-based quantitative predictions in the feed frame and in tablets closely matched the UV assay values of sampled tablets. As anticipated from the 2-wheel feed frame geometry, upon the addition of each consecutive blend, results show that the predicted concentration inside the feed frame were delayed compared with that of the tablets exiting the tablet press. For these tests, the delay was estimated to be 1.25 min. This finding highlights the importance of NIRS probe position inside the feed frame as a function of its geometry. Successive feed frame and tablet monitoring by NIRS could prove beneficial for real time release testing of tablet formulations.