کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2486264 | 1114379 | 2010 | 16 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Conformational Polymorphism of Tolbutamide: A Structural, Spectroscopic, and Thermodynamic Characterization of Burger's Forms I-IV
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کلمات کلیدی
موضوعات مرتبط
علوم پزشکی و سلامت
داروسازی، سم شناسی و علوم دارویی
اکتشاف دارویی
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چکیده انگلیسی
Crystal polymorphism of the anti-diabetic drug Tolbutamide (TB) has been studied using various analytical techniques. TB crystallizes in four polymorphic forms (Forms I-IV), which differ in their mode of packing and in molecular conformation but with similar hydrogen bonding synthon (urea tape motif). All the structures were solved from single crystal X-ray data, except for Form IV, which was solved using conventional powder X-ray diffraction (PXRD) data. The conformational differences in the TB molecule arise primarily from torsional variations in the alkyl tail which result in two types of conformers (U and chair). The packing differences are mainly due to the orientation of adjacent molecules in the hydrogen bonding networks. Based on the DSC data, thermodynamic stability relationships of polymorphic pairs were evaluated and graphically visualized in a schematic energy-temperature diagram. Form II is found to be the thermodynamically stable polymorph from absolute zero to ~Â 353Â K and beyond which Form IH is the stable polymorph. The anisotropic lattice contraction of TB polymorphs which resulted in severe variations in PXRD patterns at ambient and low temperature was highlighted. The present work also highlights and resolves several discrepancies in the published data on the structural and thermodynamic features of TB polymorphs.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Pharmaceutical Sciences - Volume 99, Issue 7, July 2010, Pages 2975-2990
Journal: Journal of Pharmaceutical Sciences - Volume 99, Issue 7, July 2010, Pages 2975-2990
نویسندگان
Satyanarayana Thirunahari, Srinivasulu Aitipamula, Pui Shan Chow, Reginald B.H. Tan,