| Literature DB >> 26886313 |
Eduardo Gomes Rodrigues de Sousa1, Erika Martins de Carvalho2, Rosane Aguiar da Silva San Gil3, Tereza Cristina Dos Santos2, Leandro Bandeira Borré4, Osvaldo Andrade Santos-Filho2, Javier Ellena5.
Abstract
Samples of efavirenz (EFZ) were evaluated to investigate the influence of the micronization process on EFZ stability. A combination of X-ray diffraction, thermal analysis, FTIR, observations of isotropic chemical shifts of (1)H in distinct solvents, their temperature dependence and spin-lattice relaxation time constants (T1), solution (1D and 2D) (13)C nuclear magnetic resonance (NMR), and solid-state (13)C NMR (CPMAS NMR) provides valuable structural information and structural elucidation of micronized EFZ and heptane-recrystallized polymorphs (EFZ/HEPT). This study revealed that the micronization process did not affect the EFZ crystalline structure. It was observed that the structure of EFZ/HEPT is in the same form as that obtained from ethyl acetate/hexane, as shown in the literature. A comparison of the solid-state NMR spectra revealed discrepancies regarding the assignments of some carbons published in the literature that have been resolved.Entities:
Keywords: (1)H NMR; (13)C CPMAS NMR; efavirenz; polymorphism
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Year: 2016 PMID： 26886313 DOI： 10.1016/j.xphs.2015.10.006
Source DB: PubMed Journal: J Pharm Sci ISSN： 0022-3549 Impact factor: 3.534