Scientia Pharmaceutica, cilt.67, sa.1, ss.57-68, 1999 (SCI-Expanded)
Two new spectrophotometric methods, ratio spectra derivative spectrophotometry and Vierordt's method for the determination of paracetamol and metamizol in a mixture were described. The first method is based on the use of first derivative of the ratio spectra of paracetamol and metamizol. Calibration graphs were linear in the range 8-40 μg/ml for paracetamol and 12-48 μg/ml for metamizol. The mean recovery of this method was 100.13 ± 0.25% and 100.09 ± 0.23% for paracetamol and metamizol, respectively. In the Vierordt's method, the amounts of paracetamol and metamizol were determined by using their zero-order spectra in 0.1N HCl. The mean recovery for paracetamol and metamizol in the method were 99.81 ± 0.43% and 99.51 ± 0.60%, respectively. Both methods were successfully applied to a pharmaceutical formulation for the determination of these drugs.