Separation and quantitation of chlortetracycline, 4-epitetracycline, 4-epianhydrotetracycline, and anhydrotetracycline in tetracycline by high-performance liquid chromatography.

The analysis of tetracycline epimers in tetracycline preparations by high-performance liquid chromatography is described. The method uses a microparticulate phenyl column (3.9 mm i.d. X 30 cm) with a step gradient of 12-22% acetonitrile in 0.2 M phosphate buffer at pH 2.2. The analysis takes 22 min. The relative standard deviations of the method (2 sigma, n = 6) for the analysis of chlortetracycline, 4-epitetracycline, 4-epianhydrotetracycline, and anhydrotetracycline in tetracycline were +/- 3.68, +/- 4.47, +/- 7.60, and +/- 2.77 %, respectively.