In this study, we use small and wide angle X-ray and neutron scattering measurements, to study the structure of concentrated sorbitol solutions and glasses at different temperatures. The analysis of the data suggests the water forms clusters with a structure resembling the low-density amorphous ice. Large-scale were detected by both small-angle X-ray and neutron measurements at lower temperatures. The observed inhomogeneities suggest areas with well-defined interfaces, potentially indicative of molecular segregation on the length scale of tens nms, although neither water nor sorbitol crystallization was observed. The local structure was similar over the entire temperature range studied, from 100K to 300K. Therefore, the appearance of larger (tens of nm) segregated structures at lower temperatures is likely due to coalescence of smaller "clusters" of water and sorbitol, without any significant structural changes on the smaller length scale. Potential practical implications of these findings to cryopreservation and properties of amorphous pharmaceuticals are discussed.
Citation: Journal of Physical Chemistry B
Pub Type: Journals
biophysics, neutrons, polymer, sugar