Studies of the internal flow process in polymers by H-1 NMR microscopy at 500 MHz

Nuclear Magnetic Resonance (NMR) microscopy was used to study the dynamics and diffusion of the internal water flow in erodible Hydroxypropylmethylcel lulose (HPMC) and Polyvinylalcohol (PVA) polymers of pharmaceutical interes t. Polymers in the form of tablets were hydrated at 37 degrees C continuous ly and monitored at regular intervals with a 500 MHz NMR microscope. The di ffusion and spin-spin relaxation time (T-2)-weighted images revealed that t he gel layer was strongly attached to the core of the tablet in both HPMC a nd PVA polymers. Spatial distribution of self diffusion coefficients (SDCs) and T-2 of the hydrating polymers were calculated from NMR microscopic ima ges. (C) 1998 Elsevier Science B.V. All rights reserved.