A trihydrate crystal of tilmicosin phosphate and a method for preparing the same

Abstract

This invention relates to a tilmicosin phosphate trihydrate crystal. The X-ray powder diffraction pattern of the crystal shows characteristic peaks at 2θ = 3.520 ± 0.2°, 6.780 ± 0.2°, 7.400 ± 0.2°, 8.360 ± 0.2°, 10.890 ± 0.2°, 15.420 ± 0.2°, and 19.680 ± 0.2°. The crystal is in powder form. The preparation method involves dissolving a certain amount of tilmicosin phosphate solid in water at room temperature and stirring magnetically until the solution becomes clear. The aqueous solution is then heated to 25°C and maintained at this temperature. Acetone is added, and the mixture is kept at this temperature for 3-4 hours. The product is then filtered and dried in a 50°C drying oven. After drying, the final tilmicosin phosphate trihydrate product is obtained. The process of this invention is stable, simple to operate, consumes little energy, and achieves a crystal product yield of over 75% and a product purity of over 99%. The crystal product has a large particle size and good thermodynamic stability, making it suitable for the manufacture and long-term storage of pharmaceutical preparations.