Rapid and accurate determination of acetaminophen and phenprobamate in binary mixtures by derivative-differential UV spectrophotometry and ratio-spectra derivative spectrophotometry

Derivative-Differential UV spectrophotometry and ratio-spectra first derivative spectrophotometry are presented for the simultaneous determination of analgesic and myorelaxan mixtures, namely acetaminophen (A)- phenprobamate (P). Derivative-Differential UV spectrophotometry is based on pH changes. The other method depends on the application ratio-spectra first derivative spectrophotometry to resolve the interference due to spectral overlapping. The proposed methods were applied to the determination of this compound in synthetic mixtures and in pharmaceutical preparations. The proposed methods, which give thoroughly comparable data, are simple and rapid, and allow one to obtain precise and accurate results.