4-Aminoantipyrine as an Analytical Reagent for the Colorimetric Determination of Tetracycline and Oxytetracycline

Abstract
A spectrophotometric method is proposed for the determination of tetracycline and oxytetracycline and their dosage forms. The suggested method depends on the reaction with 4-aminoantipyrine in the presence of an alkaline oxidising agent. A red antipyrine dye is produced. The reaction ratio has been determined. Variables such as pH, temperature, reagent concentration, stability of the colour produced have been evaluated to permit selection of the most advantageous technique. Beer's law was obeyed over the concentration range 0.04 - 0.12 mg/ml and 0.04 - 0.16 mg/ml for tetracycline and oxytetracycline respectively.