Image analysis studies of water transport and dimensional changes occurring in the early stages of hydration in cross-linked amylose matrices.
The purpose of this work was to monitor and quantify water transport and dimensional changes occurring in the early stages of hydration in cross-linked amylose (CLA) matrices using image analysis technique. Samples were prepared by direct compression of CLA-6 powder to obtain matrices of 0.17 cm thickness and 1.295 cm in diameter. A surface gel layer was formed quasiinstantaneously. The gel expansion was then constrained and the material continuity caused the outer gel layer to be in a state of biaxial compression and the internal core in a state of biaxial tension. A diffusion front preceded the gel-glass interface even in the early stages of hydration. A delayed stress-release occurred through a radial expansion of the tablet interior. This relaxation coincided with the time at which the axial diffusion fronts met. The dimensional changes had a marked impact on the kinetics of water uptake in CLA-6 tablets in early stages of hydration.
Faculté de Pharmacie, Université de Montréal, Québec, Canada. moussai@ere.umontreal.ca
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D000688:Amylose / Q000008:administration & dosage* / Q000737:chemistry; D005782:Gels; D007091:Image Processing, Computer-Assisted; D013607:Tablets; D014867:Water
D005782:Gels; D013607:Tablets; D014867:Water; D000688:Amylose