Organ-Retentive Osmotically Driven System (ORODS): A Novel Expandable Platform for in Situ Drug Delivery

Drug delivery systems capable of being retained within hollow organs allow the entire drug dose to be delivered locally to the disease site or to absorption windows for improved systemic bioavailability. A novel Organ-Retentive Osmotically Driven System (ORODS) was here proposed, obtained by assembling drug-containing units having prolonged release kinetics with osmotic units used as increasing volume compartments. Particularly, prototypes having H-shape design were conceived, manufactured and evaluated. Such devices were assembled by manually inserting a tube made of regenerated cellulose (osmotic unit) into the holes of two perforated hydrophilic tableted matrices containing paracetamol as a tracer drug. The osmotic unit was obtained by folding and gluing a plain regenerated cellulose membrane and loading sodium chloride inside. When immersed in aqueous fluids, this compartment expanded to approximately 80% of its maximum volume within 30 min of testing, and a plateau was maintained for about 6 h. Subsequently, it slowly shrank to approximately 20% of the maximum volume in 24 h, which would allow for physiological emptying of the device from hollow organs. While expanding, the osmotic unit acquired stiffness. Drug release from H-shaped ORODSs conveyed in hard-gelatin capsules was shown to be prolonged for more than 24 h.