Simultaneous determination of ibuprofen and paracetamol using derivatives of the ratio spectra method

Simple, rapid and accurate new method is described for the simultaneous determination of ibuprofen (IB) and paracetamol (PA) in two components mixture and Cetofen tablets. The method depends on the derivative of the ratio spectra DD by measurement of the amplitude of 1DD at 225.6 nm and the amplitude of 2DD at 238.9 nm for IB and PA. Calibration graphs are linear in the range 2–32 (LOD 0.53) and 2–24 (LOD 0.57) μg/ml IB and PA, respectively. The proposed method is successfully applied for simultaneous determining IB and PA in authentic mixtures and Cetofen tablets.