Characterization of crystalline and spray-dried amorphous α-cyclodextrin powders

Ho, Thao M., Howes, Tony and Bhandari, Bhesh R. (2015) Characterization of crystalline and spray-dried amorphous α-cyclodextrin powders. Powder Technology, 284 585-594. doi:10.1016/j.powtec.2015.06.027

Author Ho, Thao M.
Howes, Tony
Bhandari, Bhesh R.
Title Characterization of crystalline and spray-dried amorphous α-cyclodextrin powders
Journal name Powder Technology   Check publisher's open access policy
ISSN 1873-328X
Publication date 2015-11-01
Sub-type Article (original research)
DOI 10.1016/j.powtec.2015.06.027
Open Access Status Not Open Access
Volume 284
Start page 585
End page 594
Total pages 10
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2016
Language eng
Formatted abstract
Alpha-cyclodextrin (α-CD) powder has been used to adsorb organic compounds for various applications. In order to study the complexation of α-CD powder with guest compounds, an understanding of physical properties α-CD powder including molecular structure and water adsorption behavior is essential. Two known types of α-CD powder structure are crystalline and amorphous. However, commercial α-CD powder exists only in crystalline form and there is no reported information on properties of amorphous α-CD powder. This study aims at characterization and comparison of those properties of commercial (crystalline structure) and spray-dried α-CD powders. The results of SEM, X-ray, FTIR, DSC, PSD, TGA and 13C solid-state NMR analyses indicated that spray-dried α-CD powder was in an amorphous form with spherical shape particles (mean diameter ~ 13.28 μm) and its glass transition temperature (Tg) was about 83.4 °C. The spray-dried α-CD powder crystallized when kept above 65.30% Equilibrium Relative Humidity (ERH), corresponding to 13.70–14.97 g of moisture 100 g− 1 of dry solids. In moisture adsorption study, at the same ERH levels, amorphous α-CD powder adsorbed moisture much higher than crystalline α-CD powder did, and its adsorption isotherm data were fitted well with both BET and GAB models at a low RH range (< 65.30% ERH). A poor fitting to a wider RH range (ERH = 11.12–97.30%) of the GAB model was due to the crystallization of amorphous α-CD powders equilibrated at above 65% RH.
Keyword Amorphous α-cyclodextrin powder
Moisture adsorption
Relative humidity
Spray drying
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
School of Agriculture and Food Sciences
Official 2016 Collection
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Citation counts: TR Web of Science Citation Count  Cited 3 times in Thomson Reuters Web of Science Article | Citations
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