Investigation of the swelling behavior of Dome Matrix drug delivery modules by high-resolution X-ray computed tomography

The swelling behavior of novel Dome Matrix drug delivery modules was investigated using high-resolution X-ray computed tomography studies. The technique was exploited to investigate the swelling front position and the conditions of the interacting surfaces in situ without removing the sample from the medium during swelling. Surface and volume evolution of the glassy core under the gel layer were precisely described. Within the gel formed on the glassy core there were several particles not completely dissolved or swollen, transported from the core by the stresses due to the polymer swelling. The gel portion defined as partially swollen gel was evidenced on the convex and flat surfaces of tablets, where a line of fracture in the gel could be observed near the glassy core. In addition, the presence of solid particles in the gel layer confirmed that the translocation of particles in the swellable system affected the drug and polymer gradient within the system.