Annealing Effect Reversal by Water Sorption-Desorption and Heating above the Glass Transition Temperature-Comparison of Properties

作者：Saxena A; Jean Y C; Suryanarayanan R^*

来源：Molecular Pharmaceutics, 2013, 10(8): 3005-3012.

DOI：10.1021/mp400099r

• amorphous
• trehalose
• annealing
• glass transition temperature
• water sorption
• differential scanning calorimetry
• free volume
• positron annihilation spectroscopy

Our objective is to compare the physical properties of materials obtained from two different methods of annealing reversal, that is, water sorption-desorption (WSD) and heating above glass transition temperature (HAT). Trehalose was annealed by storing at 100 C for 120 h. The annealing effect was reversed either by WSD or HAT, and the resulting materials were characterized by differential scanning calorimetry (DSC), water sorption studies, and positron annihilation spectroscopy (PAS). While the products obtained by the two methods of annealing reversal appeared to be identical by conventional characterization methods, they exhibited pronounced differences in their water sorption behavior. Positron annihilation spectroscopy (PAS), by measuring the fractional free volume changes in the processed samples, provided a mechanistic explanation for the differences KEYWORDS: amorphous, trehalose, annealing, glass transition temperature, water sorption, free volume, positron annihilation spectroscopy

• 出版日期2013-8