| 摘要 |
The invention relates to the crystalline methanol addition product of 4-epitetracycline, which is prepared by reacting with methanol, 4-epitetracycline or a mixture thereof with tetracycline containing less than 15% of tetracycline and isolating the crystalline methanol addition product thus obtained. Preferably the reaction is carried out at 0 DEG -30 DEG C. and the 4-epitetracycline is used in the form of a salt from which it is liberated in the form of its free base during the reaction by the addition of sufficient amount of an acid or base, the acid or base thereby forming a salt soluble in methanol. Pharmaceutical compositions may be prepared with suitable carriers e.g. foods. Specifications 815,524 and 862,124 are referred to. |
