Relationship between Diffusivity of Water Molecules Inside Hydrating Tablets and Their Drug Release Behavior Elucidated by Magnetic Resonance Imaging

We reported previously that sustained release matrix tablets showed zero-order drug release without being affected by pH change. To understand drug release mechanisms more fully, we monitored the swelling and erosion of hydrating tablets using magnetic resonance imaging (MRI). Three different types of tablets comprised of polyion complex-forming materials and a hydroxypropyl methylcellulose (HPMC) were used. Proton density- and...