| 20110034692 | SPECIFIC IMPURITIES OF MONTELUKAST - The subject-matter of the invention consists in a method of removing specific impurities of montelukast of formula (I), which occur due to chemical instability of the target substance and also contaminate the substance in the preparation process. Further, methods of isolation of specific impurities of montelukast defined by formulae (V-A), (IV-A), (XIIIa-A), (XIIIb-A) and analytic methods used for the control of the production of montelukast in the pharmaceutical quality. | 02-10-2011 |