Melting behavior of pure polyethylene glycol 6000 and polyethylene glycol 6000 in solid dispersions containing diazepam or temazepam: a DSC study

Citation
S. Verheyen et al., Melting behavior of pure polyethylene glycol 6000 and polyethylene glycol 6000 in solid dispersions containing diazepam or temazepam: a DSC study, THERMOC ACT, 380(2), 2001, pp. 153-164
Citations number
16
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
153 - 164
Database
ISI
SICI code
0040-6031(200112)380:2<153:MBOPPG>2.0.ZU;2-F
Abstract
The purpose of the present study was to investigate the melting behavior of polyethylene glycol 6000 (PEG 6000) as such as well as in solid dispersion s containing diazepam or temazepam, prepared by solvent and fusion methods, using differential scanning calorimetry (DSC). It was shown that the melti ng behavior of pure PEG 6000 is influenced by the crystallization procedure applied. Fusion at 80 degreesC followed by cooling always yielded three di fferent crystal modifications. The rate of cooling (under controlled condit ions) was found to have a significant influence on the relative distributio n of the three modifications: the lower the cooling rate, the higher the re lative amount of the extended modification. Crystallization from organic so lution yielded mainly the once folded form. The presence of diazepam and te mazepam influenced the relative amount of the different PEG 6000 modificati ons. Both drugs decreased the formation of the more stable modification, wh ile the formation of the twice folded form was induced. However, in the cas e of temazepam the contribution of the extended form at higher drug levels increased in dispersions obtained from organic solutions. (C) 2001 Elsevier Science B.V. All rights reserved.