Separation of tetracyclines by high-speed liquid chromatography.

The separation of tetracycline and its four commoninpurities has been studied by high-speed liquid chromatography. A preliminary study of the effectiveness of ion-exchange, adsorption, liquid-liquid partition and reversed-phase ion-pair chromatography indicated that only the last method showed promise. By developing special hydrocarbon-bonded stationary phases a rapid and complete resolution of all five tetracyclines has been obtained within 10 min. Plate heights using a derivatised 18-mum partisil are in the range 0.15-0.3 mm. The method can be used to quantify the impurities in tetracycline at around the 1% level.