title: Colorimetric determination of certain phenol derivatives in pharmaceutical preparations.
abstract: Simple colorimetric methods are reported for determining both acetaminophen and oxyphenbutazone. These methods are based on coupling between the phenolic compound and the diazonium salts of both sulfanilic acid and p-nitroaniline; the optimum conditions for the reactions were carefully studied. For acetaminophen, the reaction products with diazosulfanilic acid and diazo-p-nitroaniline show maximum absorbance at 480 and 425 nm, respectively. The mean percentage recoveries for authentic samples were 99.5 +/- 1.1 and 100.6 +/- 0.66, respectively (P = 0.05). For oxyphenbutazone, the obtained colors showed maxima at 385 nm with diazosulfanilic acid and 490 nm with diazo-p-nitroaniline reactions. The mean percentage recoveries for authentic samples were 99.8 +/- 0.27 and 100.1 +/- 0.57, respectively (P = 0.05). The proposed methods were successfully applied to the analysis of commercial preparations; results were statistically compared with those of other methods.
mesh_terms: D000082:Acetaminophen / Q000032:analysis; D003124:Colorimetry / Q000379:methods; D004304:Dosage Forms; D007202:Indicators and Reagents; D010113:Oxyphenbutazone / Q000032:analysis; D004364:Pharmaceutical Preparations / Q000032:analysis*; D010636:Phenols / Q000032:analysis*
chemical_list: D004304:Dosage Forms; D007202:Indicators and Reagents; D004364:Pharmaceutical Preparations; D010636:Phenols; D000082:Acetaminophen; D010113:Oxyphenbutazone