Spectrofluorimetric determination of 2-aminopyridine as a potential impurity in piroxicam and tenoxicam within the pharmacopoeial limit

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.

Spectrofluorimetric determination of selected genotoxic impurities in pharmaceutical raw materials and final products

A green spectrofluorimetric method was introduced for the determination of selected genotoxic impurities; 2-aminopyridine and 3-aminopyridine in different pharmaceutical raw materials and dosage forms. The method relied on the native fluorescence of these impurities in acidic medium. The experimental conditions were carefully studied and optimized, and the method was validated according to International Council on Harmonisation (ICH) guidelines. The linear range for both analytes was 2.50–100 ng/mL with good determination coefficients of 0.9995 and 0.9992 and detection limits of 0.62 ng/mL and 0.74 ng/mL for 2-aminopyridine and 3-aminopyridine, respectively. The method was successfully applied for determination of 2-aminopyridine and 3-aminopyridine in four active pharmaceutical ingredients and nine dosage forms with satisfactory percentage recoveries and without interference from co-formulated excipients. Analytical performance of the proposed method was comparable to that of the reported methods; hence, the proposed method can be used as a simple and low-cost alternative in quality control laboratories.

Simultaneous Quantitation of Paracetamol and Lornoxicam in the Presence of Five Related Substances and Toxic Impurities by a Selective HPLC-DAD Method

OBJECTIVE

This research describes the simultaneous quantitation of paracetamol (PRM) and lornoxicam (LRX) with five of their related substances and toxic impurities, including, 4-nitrophenol (NTP), 4-aminophenol (AMP), 4-chloroacetanilide (CAC), N-phenylacetamide (NPA), and 2-aminopyridine (APD) using a specific HPLC-diode array detector (DAD) method.

METHODS

The chromatographic separation involves the use of a XTerra C18 column as the stationary phase and a mobile phase consisting of acetonitrile and 0.025 M phosphate buffer (pH 6). The separation was performed using gradient elution mode at 1.0 mL/min flow rate and detection at 260 nm for the determination of PRM and LRX. For detecting PRM and LRX in the presence of their toxic impurities, 270 nm was used. Validation of the suggested HPLC method was accomplished with regard to linearity, ranges, detection and quantitation limits, robustness, accuracy, precision, and specificity.

RESULTS

Excellent resolution of the mixture components was accomplished at retention times 4.2, 4.8, 7.4, 11.1, 13.5, 14.7, and 15.3 min for APD, AMP, PRM, NPA, LRX, NTP, and CAC, respectively. Linearity was established for PRM and LRX within concentration ranges of 10-100 and 10-60 µg/mL, respectively. The correlation coefficients obtained were >0.9997. The suggested method was confirmed to be a specific stability-indicating through the selective separation of PRM and LRX from their related substances, degradants, and impurities.

CONCLUSION

The proposed method was successfully utilized for the sensitive and selective determination of PRM and LRX in their pharmaceutical formulation.

HIGHLIGHTS

To the best of our knowledge, this is the first impurity profiling assay method for this combination in the presence of five of their toxic related substances and impurities. Taking into consideration that at least two of the studied impurities (AMP and APD) are actually reported degradation products for the main drugs, the suggested method can be considered stability-indicating as well.

Electroanalytical Determination of the Antiinflammatory Drug Tenoxicam in Pharmaceutical Dosage Forms

Objectives

The electro-oxidation behavior of the non-steroidal anti-inflammatory drug tenoxicam (TX) was studied on multiwalled carbon nanotube (MWCNT)-modified glassy carbon electrode (GCE) by cyclic voltammetry, differential pulse voltammetry (DPV), and square wave voltammetry (SWV).

Materials and Methods

The GCE was modified with MWCNT for sensitive determination of TX by voltammetric methods.

Results

The current peaks for TX occurred at around 0.520 V for DPV and 0.570 V for SWV when the potential was scanned in the positive direction. The oxidation process of TX showed irreversible and diffusion-controlled behavior. The linear responses were obtained in the range from 2×10^-7 to 1×10^-5 M with the limit of detection (LOD) 1.43×10^-9 for DPV and from 8×10^-9 to 8×10^-6 with the LOD 9.97×10^-10 for SWV in 1 M acetate buffer solution at pH 5.5.

Conclusion

Fully validated DPV and SWV were successfully applied for the determination of TX from pharmaceutical dosage form and yielded satisfying results.

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.

Development and Validation of HPTLC Method for Estimation of Tenoxicam and its Formulations

A simple, precise, accurate and rapid high performance thin layer chromatographic method has been developed and validated for the estimation of tenoxicam in the microemulsion gels. Tenoxicam was chromatographed on silica gel 60 F(254) TLC plate, as a stationary phase. The mobile phase was toluene: ethyl acetate: formic acid (6:4:0.3 v/v/v), which gave a dense and compact spot of tenoxicam with a R(f) value of 0.38±0.03. The quantification was carried out at 379 nm. The method was validated in terms of linearity, accuracy, precision and specificity. To justify the suitability, accuracy and precision of the proposed method, recovery studies were performed at three concentration levels. Statistical analysis proved that the proposed method is accurate and reproducible with linearity in the range of 100 to 400 ng. The limit of detection and limit of quantification for tenoxicam were 25 and 50 μg/spot, respectively. The proposed method can be employed for the routine analysis of tenoxicam as well as in pharmaceutical formulations.

Spectrofluorimetric and Spectrophotometric Stability-Indicating Methods for Determination of Some Oxicams Using 7-Chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl)

Two sensitive and selective spectrofluorimetric and spectrophotometric stability-indicating methods have been developed for the determination of some non-steroidal anti-inflammatory oxicam derivatives namely lornoxicam (Lx), tenoxicam (Tx) and meloxicam (Mx) after their complete alkaline hydrolysis. The methods are based on derivatization of alkaline hydrolytic products with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl). The products showed an absorption maximum at 460 nm for the three studied drugs and fluorescence emission peak at 535 nm in methanol. The color was stable for at least 48 h. The optimum conditions of the reaction were investigated and it was found that the reaction proceeds quantitatively at pH 8, after heating in a boiling water bath for 30 min. The methods were found to be linear in the ranges of 1-10 microg ml(-1) for Lx and Tx and 0.5-4.0 microg ml(-1) for Mx for spectrophotometric method, while 0.05-1.0 microg ml(-1) for Lx and Tx and 0.025-0.4 microg ml(-1) for Mx for the spectrofluorimetric method. The validity of the methods was assessed according to USP guidelines. Statistical analysis of the results revealed high accuracy and good precision. The suggested procedures could be used for the determination of the above mentioned drugs in pure and dosage forms as well as in the presence of their degradation products.