Patent ID: 8436154
Filing Date: 2013-05-07
Classification: A61P,C07H

Abstract:
1. A method for recrystallizing erythromycin, comprising the steps: (1) first dissolving erythromycin or an erythromycin salt in dichloromethane or a solvent mixture comprising dichloromethane under alkaline condition to form an erythromycin solution, wherein the pH of the erythromycin solution is from 8.6 to 12; (2) then cooling the erythromycin solution gradiently from 37° C. to −5° C. to form a suspension of erythromycin crystals, wherein a temperature is gradiently cooled from 37° C. to −5° C. at a cooling rate of 1° C. to 10° C. per hour for a recrystallization time period from 2 hours to 36 hours; (3) then separating the erythromycin crystals from the suspension; and (4) finally washing and drying the crystals.