Studies of the internal flow process in polymers by 1H 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 Hydroxypropylmethylcellulose (HPMC) and Polyvinylalcohol (PVA) polymers of pharmaceutical interest. Polymers in the form of tablets were hydrated at 37 degreesC continuously and monitored at regular intervals with a 500 MHz NMR microscope. The diffusion and spin-spin relaxation time (T2)-weighted images revealed that the gel layer was strongly attached to the core of the tablet in both HPMC and PVA polymers. Spatial distribution of self diffusion coefficients (SDCs) and T2 of the hydrating polymers were calculated from NMR microscopic images.