Scientific and technological advancements have been made in the research and development of rate-controlled oral drug delivery systems by overcoming physiological adversities, such as short gastric residence times (GRT) and unpredictable gastric emptying times (GET). Several approaches are currently utilized in the prolongation of the GRT, including floating drug delivery systems (FDDS), also known as hydrodynamically balanced systems (HBS), swelling and expanding systems, polymeric bioadhesive systems modified-shape systems, high-density systems, and other delayed gastric emptying devices. The various buoyant preparations include hollow microspheres (microballons), granules, powders, capsules, tablets (pills), and laminated films. Most of the floating systems reported in literature are single-unit systems, such as the HBS(Hydrodynamically balanced systems) and floating tablets.
