Application of derivative emission fluorescence spectroscopy for determination of ibuprofen and phenylephrine simultaneously in tablets and biological fluids.

Two sensitive, rapid, and accurate derivative emission spectrofluorimetric methods applying zero crossing techniques were developed for simultaneous determination of binary mixtures of ibuprofen (IBU) and phenylephrine hydrochloride (PHE) in pure powder, synthetic mixture and combined tablets. The proposed methods were performed via measuring the intersected drug derivative amplitude of one drug at the zero crossing points for the other one and vice versa. The two methods rely on the measurement of the combined drugs native fluorescence after excitation at 270 nm in methanol directly, followed by differentiation using first (D1) and second derivative (D2) techniques. Applying the D1, IBU was measured quantitatively at 293.1 nm at zero crossing of PHE, on the other side; PHE was measured quantitatively at 300.7 nm at zero crossing of IBU. By the same way, applying the D2, the wavelengths selected were 303.5 nm for IBU and 312.9 nm for PHE. The concentration plots of derivative fluorescence intensity were rectilinear over the range of 0.5-10 µg/mL and 0.025-0.5 µg/mL for IBU and PHE, respectively. The results obtained with average % recoveries ±â€¯RSD are 99.73 ±â€¯0.72 (IBU, D1), 99.49 ±â€¯0.95 (PHE, D1), 99.79 ±â€¯0.47 (IBU, D2), and 99.88 ±â€¯0.34 (PHE, D2) were in good agreement with the comparison method. The proposed methods offer high sensitivity that enable direct analysis of IBU and PHE in spiked human plasma. The proposed methods were entirely validated in terms of ICH guidelines.