Application of Dual Wavelength Spectrophotometry and Absorbance Ratio Method in Analysis of Compound Preparations Ⅲ.Determination of Phenylbutazone and Amidopyrine in Phenylbutazone Composite Tablets

The dual wawelength spectrophotometry and the absorbance ratio method have been used for the determination of phenylbutazone and amidopycine in phenylbutazone.Composite tablets without any preliminary separation.In the dual wavelength spectrophotometry both single and dual wavelength spectrophotometers have been used.The methods are simple and rapid.Good results have been obtained.The average recovery of phenylbutazone is 100.1-100.7%, with coefficient of variation below1.61% and the average recovery of amidopyrine is 98.17-100.0% with coefficientof variation below 0.94%.The accuracy and precision meet the requirements of analysis of he pharmaceutical preparations.