Eco-Friendly High-Performance Thin-Layer Chromatography Method for the Determination of Tenoxicam in Commercial Formulations

There is a dearth of information in the literature regarding environmentally benign high-performance thin-layer chromatography (HPTLC) methods to determine tenoxicam (TNX). Therefore, designing and validating an HPTLC method to detect TNX in commercial tablets and capsules was the goal of this investigation. The green mobile phase utilized was the combination of ethanol/water/ammonia solution (50:45:5 v/v/v). The TNX was quantified at a wavelength of 375 nm. The proposed method's greenness profile was established using the Analytical GREEnness (AGREE) approach. The proposed methodology for determining TNX was linear in the range of 25-1400 ng/band. The proposed methodology for measuring TNX was accurate (% recoveries = 98.24-101.48), precise (% RSD = 0.87-1.02), robust (% RSD = 0.87-0.94), sensitive (LOD = 0.98 ng/band and LOQ = 2.94 ng/band), and environmentally friendly. The AGREE scale for the present methodology was derived to be 0.75, indicating an outstanding greenness profile. TNX was found to be highly stable under acidic, base, and thermal stress conditions. However, it completely decomposed under oxidative stress conditions. Commercial tablets and capsules were found to have 98.46 and 101.24% TNX, respectively. This finding supports the validity of the current methodology for measuring TNX in commercial formulations. The outcomes of this work showed that the proposed eco-friendly HPTLC methodology can be used for the routine analysis of TNX in commercial formulations.

Optimizations of the Conditions for Ceftobiprole Determination in a Complex Matrix

A quick and accurate chromatographic–densitometric method for the determination of ceftobiprole in biological material (whole blood and urine) was developed. Preparation of the test sample required extraction of the drug from the matrix and was carried out by testing methanol or acetone as extracting agents, which were successfully used to isolate ceftobiprole from biological material. Under optimization of the procedure, various stationary and mobile phases were tested. Lastly, HPTLC cellulose plates and a mixture containing ethanol, 2-propanol, glacial acetic acid, and water in the ratio 4:4:1:3 (v/v/v/v) were chosen. Densitometric detection was made at a maximum absorbance of 316 nm. The developed method was validated; a linear function of the ceftobiprole concentration was obtained in the range of 2.4–72 µg/mL (r > 0.99) for both methanol and acetone solutions. The average accuracy of the devised method was measured at nearly 100%; nevertheless, the limit of the quantification was at 8.92 for methanol and 9.14 µg/mL for acetone solution. Therefore, the above method can be successfully used to ceftobiprole in biological material.

High-Performance Thin-Layer Chromatography (HPTLC) Method for Identification of Meloxicam and Piroxicam

Background: High-performance thin-layer chromatography (HPTLC) is an advantageous, modern analytical technique based on the principles of thin-layer chromatography (TLC), which provides essential benefits, such as improved sample application, better and faster separation, and less mobile phase usage. The aim of this work was to develop a simple and rapid HPTLC method that could be used for the identification of meloxicam and piroxicam. Methods: HPTLC. An analysis was carried out using silica gel 60 F254 glass TLC plates and as the mobile phase: hexane: ethyl acetate: glacial acetic acid, in a ratio of 65:30:5 v/v/v. For the standard solution preparation, ethanol was used. Front: 60 mm. Detection was performed at 366 nm. Results: The Rf value for meloxicam was 0.81 and the Rf value for piroxicam was 0.57. The proposed method can be used in the detection of the analyzed compounds in very low concentrations. It was established that the detection limit of meloxicam was 0.04 μg per band and that of piroxicam was 0.05 μg per band. It was also established that the quantitation limit of meloxicam was 0.12 μg per band and that of piroxicam was 0.15 μg per band. Conclusions: The proposed method is simple, sensitive, stable, cost effective, and eco-friendly. It could be used in research or for routine quality control purposes.

Nitrogen-Doped Graphene-Based Sensor for Electrochemical Detection of Piroxicam, a NSAID Drug for COVID-19 Patients

Nitrogen-doped graphene (NGr) was synthesized by the hydrothermal method using urea as a reducing and doping agent for graphene oxide (GO). The crystalline structure of GO was revealed by the XRD intense peak recorded at 2θ = 11.4°, indicating that the interlayer distance within the structure was large (d = 0.77 nm), and the number of layers (n) was 9. Further, the transformation of GO in NGr also led to the decrease in the interlayer distance and number of layers (d = 0.387 nm; n = 3). As indicated by elemental analysis, the concentration of nitrogen in the NGr sample was 6 wt%. Next, the comparison between the performance of bare GC and the graphene-modified electrode (NGr/GC) towards piroxicam (PIR) detection was studied. Significant differences were observed between the two electrodes. Hence, in the case of bare GC, the oxidation signal of PIR was very broad and appeared at a high potential (+0.7 V). In contrast, the signal recorded with the NGr/GC electrode was significantly higher (four times) and shifted towards lower potentials (+0.54 V), proving the electro-catalytic effect of nitrogen-doped graphene. The NGr/GC electrode was also tested for its ability to detect piroxicam in pharmaceutical drugs (Flamexin), giving excellent recoveries.

Five spectrophotometric methods for simultaneous determination of Amlodipine besylate and celecoxib in presence of its toxic impurity

Five simple, selective and accurate spectrophotometric methods have been applied and developed for first time for simultaneous determination of amlodipine besylate (AML) and celecoxib (CEL) in presence of one harmful impurity, 4-methylacetophenone (MAP), in their ternary mixture without prior separation. Those spectrophotometric methods were developed and called: dual wave length in ratio spectra (DWRS), successive ratio-derivative spectra (SDR), modified absorption factor method (MAFM), modified amplitude center method (MACM) and first derivative -zero crossing coupled with amplitude factor method (FDAF). These methods include various steps using zero /or ratio /or derivative spectra and some mathematical techniques. Linear calibration curves were constructed over the concentration range of 2-100, 10-200 and 0.5-20 µg/mL for AML, CEL and MAP, respectively. High sensitivity with low LOD values 0.583, 3.118 and 0.147 for AML, CEL and MAP, respectively were obtained. Moreover, validation of the proposed methods was achieved according to ICH guidelines and satisfactory results were obtained indicating that the developed methods can be used for quality control analysis of AML and CEL concerning its impurity. No significant difference was observed when the obtained results of the developed methods were statistically compared with the reported HPLC method.

Validated green chromatographic methods for determination of amlodipine and celecoxib in presence of methylacetophenone

Aim: Green, accurate and rapid methods, namely LC-MS/MS and thin layer chromatography-densitometric methods, were developed for determination of amlodipine besylate and celecoxib in presence of its process-related impurities, 4-methylacetophenone in pure and formulated tablets. Results: LC-MS/MS was achieved on ZORBAX Eclipse Plus C₁₈ column using methanol:aqueous solution of 5 mM formic acid (95:5 v/v). High sensitivity with low limit of detection values 0.00028, 0.00027 and 0.0003 for amlodipine, celecoxib and 4-methylacetophenone, respectively were obtained. While, thin layer chromatography-densitometric was established using methanol:water:ammonia (70:25:1.5, by volume). Good linearity was obtained in the range of 0.1-10 μg/band, 1-150 μg/band and 0.01-2 μg/band for amlodipine, celecoxib and 4-methylacetophenone, respectively. Conclusion: The proposed method validation was achieved according to ICH guidelines. Those methods possess advantages of being ecofriendly methods which permit their application in quality control laboratories.

Piroxicam

A comprehensive profile of piroxicam including the nomenclatures, formulae, elemental composition, appearance, uses and applications. The methods which were utilized for the preparation of the drug substance and their respective schemes are outlined. The physical characteristics of the drug including the ionization constant, solubility, x-ray powder diffraction pattern, differential scanning calorimetry, thermal behavior and spectroscopic studies are described. The methods which were used for the analysis of the drug substance in bulk drug and/or in pharmaceutical formulations including the compendial, spectrophotometric, electrochemical and the chromatographic methods are reported. The stability, toxicity, pharmacokinetics, bioavailability, drug evaluation, comparison, in addition to compiled reviews on the drug substance are involved. Finally, more than four hundred and fifty references are listed at the end of this profile.