Abstract:
:Amorphous dispersions provide an excellent way of increasing dissolution rates of poorly soluble drugs, but there may be concerns about stability. One way of assessing the stability of amorphous is the study of relaxation. In this study the relaxation at the surface of amorphous solid dispersions (SDs) was evaluated using inverse gas chromatography (IGC). A SD containing 70% indometacin and 30% PVP K30 was prepared by melt-quenching. The SD was put into the IGC and heated to 17 degrees C below T(g) for aging, during which time decane was injected repeatedly. The retention volume of decane decreased with aging time, indicating that the sample relaxed at the surface. During this storage no crystallization was observed by PXRD and DSC. Therefore, it is obvious that the change in this retention volume is due to the structural relaxation of the amorphous SD. The data of retention volume showed a good fit on a Kohlraush-Williams-Watts (KWW) equation and the indicator of the relaxation, tau(beta), was estimated. It was much lower than that of bulk relaxation estimated by DSC. Therefore, it can be concluded that the structural relaxation at the surface happens faster than that of the bulk. The potential significance of these findings is discussed.
journal_name
J Pharm Scijournal_title
Journal of pharmaceutical sciencesauthors
Hasegawa S,Ke P,Buckton Gdoi
10.1002/jps.21573subject
Has Abstractpub_date
2009-06-01 00:00:00pages
2133-9issue
6eissn
0022-3549issn
1520-6017pii
S0022-3549(16)32981-1journal_volume
98pub_type
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