Naidong W, Verresen K, Busson R, Roets E, Hoogmartens J
Katholieke Universiteit Leuven, Institut voor Farmaceutische Wetenschappen, Belgium.
J Chromatogr. 1991 Nov 8;586(1):67-72. doi: 10.1016/0021-9673(91)80026-d.
Isolation of doxycycline, 6-epidoxycycline and 2-acetyl-2-decaboxamidometacycline from commercial metacycline was achieved by preparative column liquid chromatography on silica gel, previously impregnated with edetate (EDTA). Careful control of the pH of EDTA allowed fine tuning of the separation. The mobile phases were composed of dichloromethane, methanol and .1 mM EDTA at pH 9.0 or 6.0. Structures were confirmed with nuclear magnetic resonance spectroscopy. The presence of doxycycline and its 6-epimer in commercial metacycline has not previously been described. The presence of the 2-acetyl derivative was not surprising since analogous 2-acetyl derivatives have been identified in other tetracyclines.
通过在预先用乙二胺四乙酸（EDTA）浸渍的硅胶上进行制备柱液相色谱，从市售的美他环素中分离出多西环素、6-表环氧美他环素和2-乙酰基-2-去甲酰胺基美他环素。对EDTA的pH值进行仔细控制可实现分离的微调。流动相由二氯甲烷、甲醇和pH值为9.0或6.0的0.1 mM EDTA组成。通过核磁共振光谱确认结构。市售美他环素中多西环素及其6-差向异构体的存在此前尚未见报道。2-乙酰基衍生物的存在并不令人惊讶，因为在其他四环素中已鉴定出类似的2-乙酰基衍生物。
