Document Detail

Discrimination of polymorphic forms of a drug product by localized thermal analysis.
MedLine Citation:
PMID:  10810002     Owner:  NLM     Status:  MEDLINE    
In chemical processing, it is important to distinguish between and identify polymorphic forms. We demonstrate the novel use of scanning thermal microscopy (SThM) and localized thermal analysis to distinguish and identify polymorphic forms of the drug cimetidine. These forms cannot be resolved by classical bulk thermal analysis. SThM reveals a sample consisting of a 50 : 50 mixture of the polymorphs contains regions of different thermal conductivity, corresponding to the different polymorphs. Localized thermal analysis of small volumes of pure polymorphic samples (approximately 50 microm3) shows that the origin of the thermal conductivity contrast lies, at least in part, with the presence of a surface water layer on the more hydrophilic polymorph.
G H Sanders; C J Roberts; A Danesh; A J Murray; D M Price; M C Davies; S J Tendler; M J Wilkins
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of microscopy     Volume:  198     ISSN:  0022-2720     ISO Abbreviation:  J Microsc     Publication Date:  2000 May 
Date Detail:
Created Date:  2000-07-06     Completed Date:  2000-07-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0204522     Medline TA:  J Microsc     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  77-81     Citation Subset:  IM    
Laboratory of Biophysics and Surface Analysis, School of Pharmaceutical Sciences, University of Nottingham, UK.
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MeSH Terms
Chemistry, Pharmaceutical
Cimetidine / chemistry*
Differential Thermal Analysis
Histamine H2 Antagonists / chemistry*
Microscopy, Electron, Scanning / methods
Molecular Structure
Reg. No./Substance:
0/Histamine H2 Antagonists; 51481-61-9/Cimetidine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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