Preparation and characterization of rivaroxaban as an anticoagulant

The preparation of polymorphic forms of rivaroxaban was carried out using a recrystallization method based on that for crystal form-Ⅰ. Preparation methods were developed for two crystal forms-Ⅱ (medicinal crystal form) and five crystal forms-Ⅳ and the crystals were then characterized. The crystalline form was identified by applying modern analytical means including X-ray powder diffraction (PXRD), differential scanning calorimetry (DSC), element analysis (EA), mass spectrometry (MS), and infrared spectrum (IR), and the morphology of different crystal forms was observed by scanning electron microscopy (SEM). The results show that the PXRD and DSC characteristics of prepared crystal forms-II and IV are consistent with those described in patents at home and abroad, and the test results with EA, MS and IR are in accordance with the chemical structure of rivaroxaban. The crystal form-I is lamellar, the crystal form-II is linear and crystalline form-IV is striped as determined by SEM. In summary, the methods for preparing crystal form-II and form-IV are reliable, the required reagents are easily available, the experimental conditions are easy to implement and the preparation process is simple. Our study provides a new reference for the production and application of rivaroxaban.