Bridging the structure gap between pellets in artificial dissolution media and in gastro-intestinal tract in rats.

Changes in structure of oral solid dosage forms (OSDF) elementally determine the drug release and its therapeutic effects. In this research, synchrotron radiation X-ray micro-computed tomography was utilized to visualize the 3D structure of enteric coated pellets recovered from the gastrointestinal tract of rats. The structures of pellets in solid state and compendium media were measured. Pellets underwent morphological and structural changes which differed significantly from those compendium media. Thus, optimizations of the dissolution media were performed to mimic the appropriate conditions by introducing pepsin and glass microspheres in media. The sphericity, pellet volume, pore volume and porosity of the esomeprazole magnesium pellets in stomach for 2 h were recorded 0.47, 1.55 × 10 μm, 0.44 × 10 μm and 27.6%, respectively. After adding pepsin and glass microspheres, the above parameters reached to 0.44, 1.64 × 10 μm, 0.38 × 10 μm and 23.0%, respectively. Omeprazole magnesium pellets behaved similarly. The structural features of pellets between media and condition were bridged successfully in terms of 3D structures to ensure better design, characterization and quality control of advanced OSDF.