Semiautomated method for analysis of enteric-coated and plain coated diethylstilbestrol tablets

Abstract

A semiautomated fluorometric method for the analysis of enteric-coated and plain coated diethylstilbestrol tablets is presented. To eliminate interferences from tablet excipients, diethylstilbestrol is extracted into an organic solvent and then into a basic aqueous solution. After UV irradiation, a product of diethylstilbestrol is formed from which a fluorophore is produced chemically. The fluorescence is measured at an excitation wavelength of 335nm and an emission wavelength of 410nm. The coefficient of variation measured for the semiautomated procedure was 0.59%. Assay results agreed well with the USP procedure for tablets containing >1mg of diethylstilbestrol. Tablet dyes and excipients interfered in the USP procedure, which yielded low results for tablets containing < 1mg of diethylstilbestrol. Standard recovery data and assays of tablet composites showed that dyes and other excipients do not interfere with the semiautomated procedure.