SIMULTANEOUS DETERMINATION OF PARACETAMOL AND TAPENTADOL IN TABLETS BY RATIO SPECTRA DERIVATIVE SPECTROPHOTOMETRY

The application of the ratio spectra derivative spectrophotometry to the simultaneous determination of Paracetamol (PCM) and Tapentadol (TAP) in combined pharmaceutical tablets is presented. The spectrophotometric procedure is based on the use of the first derivative of the ratio spectra obtained by dividing the absorption spectrum of the binary mixtures by a standard spectrum of one of the compounds. The first derivative amplitudes were measured at 220 and 232 nm for the assay of TAP and PCM, respectively. Calibration graphs were established for 1-5 μg mL-1 for TAP and 6.5-32.5 μg mL-1 for PCM in binary mixture. The detection limits for TAP and PCM were found 0.098 and 0.595 μg mL-1, respectively, while the quantification limits were 0.298 μg mL-1 for TAP and 1.805 μg/ml for PCM. The relative standard deviations were found to be less than 2%, indicating reasonable repeatability of both methods. The proposed methods were hence validated as per ICH guidelines and successfully applied to the determination of these drugs in commercial tablets.