Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2486668 | Journal of Pharmaceutical Sciences | 2011 | 10 Pages |
Abstract
The “aging-driven” decomposition of zolpidem hemitartrate hemihydrate (form A) has been followed by X-ray powder diffraction (XRPD), and the crystal and molecular structures of the decomposition products studied by single-crystal methods. The process is very similar to the “thermally driven” one, recently described in the literature for form E (Halasz and Dinnebier. 2010. J Pharm Sci 99(2): 871-874), resulting in a two-phase system: the neutral free base (common to both decomposition processes) and, in the present case, a novel zolpidem tartrate monohydrate, unique to the “aging-driven” decomposition. Our room-temperature single-crystal analysis gives for the free base comparable results as the high-temperature XRPD ones already reported by Halasz and Dinnebier: orthorhombic, Pcba, a = 9.6360(10) Ã
, b = 18.2690(5) Ã
, c = 18.4980(11) Ã
, and VÂ =Â 3256.4(4)Â Ã
3. The unreported zolpidem tartrate monohydrate instead crystallizes in monoclinic P21, which, for comparison purposes, we treated in the nonstandard setting P1121 with a = 20.7582(9) Ã
, b = 15.2331(5) Ã
, c = 7.2420(2) Ã
, γ = 90.826(2)°, and V = 2289.73(14) Ã
3. The structure presents two complete moieties in the asymmetric unit (z = 4, zâ²Â = 2). The different phases obtained in both decompositions are readily explained, considering the diverse genesis of both processes.
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Authors
Daniel R. Vega, Ricardo Baggio, Mariana Roca, Dora Tombari,