Analysis of Tetracycline in Pharmaceutical Preparations by Improved High‐Performance Liquid Chromatographic Method

Abstract

AbstractThe analysis of tetracycline in pharmaceutical preparations by an improved high‐performance liquid chromatographic (HPLC) method is described. The improved method uses a 30‐cm long stainless steel column packed with octadecylsilane bonded on 10‐μm silica gel, with a linear gradient from 10 to 60% acetonitrile in pH 2,5, 0.02 M phosphate buffer in 11min at a flow rate of 1.0ml/min (68 atm). The resolution functions obtained between 4‐epitetracycline and tetracycline and between 4‐epianhydrotetracycline and anhydrotetracycline were improved 150 and 250%, respectively. The analysis of a tetracycline sample takes approximately 16 min; the original method required more than 25min. The relative standard deviation for the analysis of tetracycline powder was 0.66%, and the recovery of 4‐epianhydrotetracycline added in tetracycline was linear over the 0.3‐100% range. Recovery of tetracycline from products was better than 99.6% at label concentration. The drug content of products as calculated from the HPLC data agreed well with those of the microbiological assay methods.