Determination of phenacetin and caffeine in compound acetylsalicylic acid tablets by multiple regression spectrophotometry

Key words: 
• multiple regression spectrophotometry /
• compound acetylsalicylic acid tablets /
• phenacetin /
• caffeine /
• determination

Abstract: OBJECTIVE To determine phenacetin and caffeine in compound acetylsalicylic acid tablets. METHODS Multiple regression spectrophotometry was adopted as follow:The sample is dissolved in ethanol,add solution of 02mol/L NaOH to hydrolysis acetylsalicylic acid,the components are determined in phosphate salt buffet (pH 6.5). RESULTS The average recoveries for phenacetin and caffeine were 99.8% and 99.9%,with RSD 0.72% and 0.52%,respectively. CONCLUSION Accuracy of the method was compared with official quantitative analysis and no significant difference was found.