四环类抗生素的反相制备层析——Ⅰ.应用硅胶RP-2层析分离四环类抗生素

反相硅胶是一种新的层析介质,近年来已广泛应用于天然产物的分离和纯化中,为确证反相硅胶RP-2能否有效地分离四环类抗生素,研究了不同溶剂、pH、酸类条件下四环素、金霉素、甲烯土霉素和强力霉素在硅酸RP-2柱上的洗脱特性。据此确定了硅胶RP-2柱层析分离四环素、金霉素,甲烯土霉素和强力霉素的条件。虽然甲烯土霉素和强力霉素在此条件下 难以分离,但应用醋酸乙酯饱和的水(pH6)或醋酸乙酯饱和的草酸溶液(pH3)作洗脱溶剂能有效地从上述四种四环类抗生素中分离出四环素和金霉素。随着草酸浓度的增加和pH的降低,甲烯土霉素和强力霉素也能得到较好的分离。醋酸乙酯饱和的0.05mol/L草酸溶液(pH3)则是从上述四种抗生素中分离出四环素和金霉素的最适宜的溶剂系统。这是一快速、简便的制备性分离四环类抗生素的方法。并且使用过的硅胶RP-2经过适当处理之后还可反复使用。

SEPARATION OF TETRACYCLINES BY SILICA GEL RP-2 COLUMN CHROMATOGRAPHY

Reverse phase Silice gel is a comparatirely new ehromatographie medium. Recently it has been used widely for separation and purification of uatural products.In order to see whether the silica gel RP-2 would be effective for chromatograp-hy of mixtures of tetracyclines, the elution characteristics of tetracycline, chlortetra-cycline, methacycline and doxycycline were studied on a silica gel 60 silanized RP-2 column under various conditions of solvent,pH and added acids.HPLC proved to be outstanding for separation of tetracyclines on an analytical scale. For preparative separation, tetracycime and chlortetracycline can be separated rapidly and efficiently from each other and from the mixture of methacycline and doxycyciine using silica gel 60 silanized RP-2 column coditions, however, were not found for separation of methacycline from doxycycline on a preparative scale.Tetracycline can be separated efficiently from its mixture with chlortetracycline, methacycline and doxycyciine by using ethyl acetate saturated-water (pH6.0) or ethyl acetate saturated-0.01mol/L oxalic acid (pH3.0) as elution solvent.The chlortetracycline and methacycline or doxycyciine also can be separated efficiently at lower pH values or with increased concentration of oxalic acid. The results show that ethyl acetate saturated-0.05mol/L oxalic acid (pH3.0) was the optimal solvent for the separation of tetracycline, chlortetracycline from methacycline and doxycycline.