Green Constant-wavelength Concurrent Selective Fluorescence Method for Assay of Ibuprofen and Chlorzoxazone in Presence of Chlorzoxazone Degradation Product

Lower back pain is a universal dilemma leaving a negative effect on both health and life quality. It was found that a fixed dose combination of chlorzoxazone and ibuprofen gave a higher efficiency than analgesic alone in treatment of acute lower back pain. Based on the significant benefit of that combination, a green, sensitive, rapid, direct, and cost-effective method is created for concurrent determination of ibuprofen and chlorzoxazone in presence of 2-amino para chlorophenol (a synthetic precursor and potential impurity of chlorzoxazone) adopting the synchronous spectrofluorimetric technique. Synchronous spectrofluorimetric technique is adopted to avoid the highly overlapped native spectra of both drugs. The synchronous spectrofluorometric method was applied at Δλ = 50 nm, ibuprofen was measured at 227 nm while chlorzoxazone was measured at 282 nm with no hindering from one to another. The various experimental variables affecting the performance of the suggested technique were explored and adjusted. The suggested technique showed good linearity from 0.02 to 0.6 and 0.1 to 5.0 µg/mL for ibuprofen and chlorzoxazone, respectively. The produced detection limits were 0.27 × 10(–3) and 0.03, while the quantitation limits were 0.82 × 10(–3) and 0.09 µg/mL for ibuprofen and chlorzoxazone, respectively. The suggested approach was successfully applied for the analysis of the studied drugs in the synthetic mixture, different pharmaceutical preparations, and spiked human plasma. The suggested technique was validated with respect to the International Council of Harmonization (ICH) recommendations. The suggested technique was found to be simpler and greener with lower cost compared to the earlier reported methods which required complicated techniques, longer time of analysis, and less safe solvents and reagents. Green profile assessment for the developed method compared with the reported spectrofluorometric method was performed using four assessment tools. These tools confirmed that the recommended technique attained the most possible green parameters, so it could be used as a greener option in routine quality control for analyzing the two drugs in genuine form and pharmaceutical preparations.