Tigecycline crystalline forms and processes for preparation thereof
The present invention relates to solid crystalline Tigecycline, and crystalline forms thereof.
1. A crystalline form of Tigecycline characterized by a powder XRD pattern having peaks at 6.8, 9.5, 9.8, 12.1, 12.6, 18.1, 20.2, 21.6, 23.3, and 26.8±0.2 degrees 2-theta.
2. The crystalline Tigecycline of claim 1 , further characterized by a powder XRD pattern as depicted in FIG. 3 .
3. The crystalline Tigecycline of claim 1 , wherein said crystalline Tigecycline is present in a composition having less than 20% of any other form of Tigecycline.
4. The crystalline Tigecycline of claim 3 , wherein said crystalline Tigecycline is present in a composition having less than 10% of any other form of Tigecycline.
5. The crystalline Tigecycline of claim 4 , wherein said crystalline Tigecycline is present in a composition having less than 5% of any other form of Tigecycline.
6. The crystalline Tigecycline of claim 5 , wherein said crystalline Tigecycline is present in a pure form.
7. A process for preparing the crystalline form of Tigecycline of claim 1 , comprising crystallizing Tigecycline from acetonitrile.
8. The process of claim 7 , wherein said crystallizing comprises the steps of:
a) preparing a solution of Tigecycline in acetonitrile; and
b) evaporating said acetonitrile to obtain said crystalline form.
9. The process of claim 8 , wherein said solution is maintained at a temperature of about −10° C. to about 30° C.
10. The process of claim 9 , wherein said solution is maintained at a temperature of about 0° C. to about 25° C.
11. A process for preparing the crystalline form of Tigecycline of claim 1 , comprising crystallizing Tigecycline from a mixture of dimethoxyethane and n-heptane, wherein said crystallizing comprises the steps of:
a) preparing a solution of Tigecycline in dimethoxyethane;
b) admixing n-heptane into said solution to obtain a suspension; and
c) recovering said crystalline Tigecycline from said suspension.