Analysis of Mixtures of Doxycycline and Oxytetracycline in Pharmaceutical Preparations by First Derivative Fluorimetry

The utility of first-derivative fluorimetry for the determination of doxycycline and oxytetracycline through the formation of their chelates with aluminium, is discussed. Mixtures of these compounds were determined by first-derivative fluorimetry with linear calibration graphs established between 0.2 and 1.4 μgml−1 for doxycycline and between 0.05 and 0.6 μgml−1 for oxytetracycline. The application of the method to the analysis of these compounds in pharmaceutical preparations is described and a statistical evaluation of the experimental results is reported.