Eco-friendly simultaneous multi-spectrophotometric estimation of the newly approved drug combination of celecoxib and tramadol hydrochloride tablets in its dosage form.

Food and Drug Administration (FDA) recently approved co-formulated celecoxib and tramadol for the treatment of acute pain in adults. Three spectrophotometric methods were efficiently applied to estimate the co-formulated Celecoxib and Tramadol in their tablets; second derivative 2D-spectrophotometry technique (method I), induced dual-wavelength technique (method II) and dual-wavelength resolution technique (method III). The proposed methods were successfully validated following the International Council for Harmonisation (ICH) guidelines and statistically assessed based on the correlation coefficients, relative standard deviations as well as detection and quantitation limits. The obtained results revealed non-significant differences compared to the reported results as revealed by the variance ratio F test and Student t test. Moreover, the applied techniques were further assessed concerning their greenness based on the analytical eco-scale method revealing an excellent green scale with a final score of 95. The proposed spectrophotometric techniques could be applied for the routine analysis and quality control of the studied drugs in their dosage form.

Kinetics investigation and determination of pipoxolan hydrochloride and its degradant using liquid chromatography.

An LC method was developed for the quantitative determination of pipoxolan hydrochloride (PPH) and its degradant. Forced degradation studies were performed on bulk sample using acid (1 M hydrochloric acid), alkaline (0.2 M sodium hydroxide), oxidation (0.33% hydrogen peroxide), heat (70 degrees C), and photolytic degradation. The chromatographic method was fine-tuned using the samples generated from forced degradation studies. Good resolution between the peaks corresponding to the degradants and the analyte was achieved on a Discovery C18 LC column (25 cm x 4.6 mm id, 5 pm particle size). The mobile phase was methanol-10 mM sodium dihydrogen phosphate (60+40, v/v); pH was adjusted to 6.5 using 0.2 M sodium hydroxide. Quantitation was achieved with UV detection at 214 nm based on peak area. The proposed LC method was used to investigate the kinetics of acidic and alkaline degradation processes of PPH at different temperatures, and the apparent pseudo-first-order rate constant, half-life, and activation energy were calculated. The pH-rate profiles of degradation of PPH in Britton-Robinson buffer solutions within the pH range 2-12 were studied. The developed method was validated with respect to linearity, accuracy, precision, and robustness. Forced degradation studies proved the stability-indicating power of the method.

Rapid and simultaneous determination of antioxidant markers and caffeine in commercial teas and dietary supplements by HPLC-DAD.

A simple and fast reverse-phase high-performance liquid chromatography procedure coupled with photodiode array detector (RP-HPLC-DAD) was developed and validated for the analysis of major catechins, proanthocyanidin (procyanidin B2) and caffeine in 25 different natural complex matrices containing Camellia sinensis L. and/or grape seed extracts, two popular plant extracts that have been widely used as natural antioxidants in various food and beverage applications. Using an isocratic elution system, separation of all compounds was achieved within 12 min. Excellent linearity was observed for all of the standard calibration curves, and the correlation coefficients were above 0.9997. Limits of detection for all of the analyzed compounds ranged between 2.80×10(-3) and 2.51×10(-2) µg mL(-1); limits of quantitation ranged between 9.30×10(-3) and 8.36×10(-2) µg mL(-1). The developed method was found to be accurate and sensitive and is ideally suited for rapid, routine analysis of principal components in these well-known natural antioxidants.

High-performance liquid chromatography quantification of principal antioxidants in black seed (Nigella sativa L.) phytopharmaceuticals.

A new, simple, sensitive, rapid, and accurate isocratic RP-HPLC method was developed and validated for simultaneous analysis of the principal antioxidants of Nigella sativa, i.e., thymoquinone (TQ), carvacrol (CR), and its isomer thymol (THY), in different phytopharmaceuticals. The mobile phase was water-methanol (40 + 60, v/v) at a flow rate of 1.5 mL/min. Quantification was achieved with UV detection at 254 nm, based on peak area. The method was validated for linearity, accuracy, precision, selectivity, and robustness. The proposed method is stability-indicating for determination of TQ in the presence of its degradants. The LOD and LOQ (microg/mL) were, respectively, 0.006 and 0.021 for TQ, 0.002 and 0.006 for CR, and 0.027 and 0.090 for THY. The mean recoveries measured at three concentrations were higher than 99%, with RSD <2%. This analytical method is suitable for quality control of the marker substances in this widely used natural protective and curative remedy.