Feasibility of using isothermal microcalorimetry to evaluate the physical stability of amorphous nifedipine and phenobarbital

Citation
Y. Aso et al., Feasibility of using isothermal microcalorimetry to evaluate the physical stability of amorphous nifedipine and phenobarbital, THERMOC ACT, 380(2), 2001, pp. 199-204
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
THERMOCHIMICA ACTA
ISSN journal
0040-6031 → ACNP
Volume
380
Issue
2
Year of publication
2001
Pages
199 - 204
Database
ISI
SICI code
0040-6031(200112)380:2<199:FOUIMT>2.0.ZU;2-I
Abstract
Feasibility of microcalorimetry to evaluate the physical stability of amorp hous drugs was studied. Amorphous forms of nifedipine and phenobarbital wer e prepared by melting and subsequent cooling in a differential scanning cal orimetry (DSC) sample pan, and their heats of crystallization were monitore d by isothermal microcalorimetry. The time required for 10% of the amorphou s drug to crystallize (t(90)), a direct measure of the crystallization rate , could be obtained from a single microcalorimetric trace of the amorphous nifedipine or phenobarbital. The t(90) values were also determined by conve ntional storage studies in which the heat of crystallization was determined by DSC. The t(90) values obtained by microcalorimetry were consistent with those obtained by DSC, within experimental error, indicating that microcal orimetry is a useful method for evaluating the physical stability of amorph ous drugs. (C) 2001 Elsevier Science B.V. All rights reserved.