| Full text | |
| Author(s): |
Carvalho, Jr., Paulo S.
;
Ellena, Javier
;
Yufit, Dmitry S.
;
Howard, Judith A. K.
Total Authors: 4
|
| Document type: | Journal article |
| Source: | Crystal Growth & Design; v. 16, n. 7, p. 3875-3883, JUL 2016. |
| Web of Science Citations: | 11 |
| Abstract | |
Polymorphism in racemic pharmaceutical compounds is relatively unexplored. However, this phenomenon may provide an additional tool to crystal engineering, opening the doors to rational design of chiral resolution, chiral enrichment, and chiral purification of pharmaceutical compounds. In this work we report two racemic polymorphs occurring for the nitrate salt of the antidepressant drug fluoxetine (FLX): a racemate (P2(1)/n, Z = 4, Z' = 1) and a kryptoracemate (Pca2(1), Z = 4, Z' = 2). The relative stability of these polymorphs was established through a combination of techniques, namely, differential scanning calorimetric (DSC), thermogravimetric analysis (TGA), hot stage microscopy (HSM), and solubility measurements. Though the two polymorphs share some structural features, the N+-H center dot center dot center dot O- hydrogen bonds have created dissimilar racemic motifs in their packing, resulting in different enantiomer orientations. The racemate is more stable over the temperature ranges we studied and is monotropically related to kryptoracemate. In our experiments, the obtaining of non-centrosymmetric lattice of racemic fluoxetine nitrate was shown to be dependent on kinetic factors. The thermodynamic relationships between both polymorphs were further confirmed by measuring their water solubility at 20 and 37 degrees C. (AU) | |
| FAPESP's process: | 12/05616-7 - Solid-state characterization of anticonvulsant and antidepressant phamaceutical compounds: Design of new crystal forms. |
| Grantee: | Paulo de Sousa Carvalho Júnior |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 14/12429-4 - Development, evaluation and characterization of new solid phases of selective serotonin reuptake inhibitors |
| Grantee: | Paulo de Sousa Carvalho Júnior |
| Support Opportunities: | Scholarships abroad - Research Internship - Doctorate |