Patent ID: 9409940
Filing Date: 2016-08-09
CPC Classification: C07D,C07H

Claim Text:
1. A method for preparing erythromycin thiocyanate, comprising: a) dissolving erythromycin or an erythromycin salt or a mixture thereof in acetone or a mixed solvent comprising acetone under alkaline condition to form a solution of the erythromycin or erythromycin salt; b) adding a thiocyanate salt into the solution under alkaline condition; c) adjusting the pH of the solution to from 6.0 to 8.0; and d) forming crystals of erythromycin thiocyanate by cooling the solution to a temperature from 0° C. to 10° C., wherein the solution in step a and step b is kept at a temperature from 35° C. to 50° C. and wherein the content of erythromycin thiocyanate A in the crystals of erythromycin thiocyanate is more than 79%, based on the total weight of the erythromycin thiocyanate.