Floating Drug Delivery Systems: An Advanced Approach for Oral Controlled Drug Release

Oral drug delivery remains the most widely accepted route of administration due to its cost-effectiveness, ease of use, patient compliance, and flexibility in dosage forms. However, it is often limited by rapid gastrointestinal transit, short gastric residence time, and poor bioavailability of certain drugs. To address these challenges, Floating Drug Delivery Systems (FDDS) have emerged as a promising gastro-retentive approach. FDDS, first introduced by Davis in 1968, are designed to remain buoyant in gastric fluids, thereby prolonging gastric residence time and ensuring controlled release of drugs at the site of absorption. These systems are particularly advantageous for drugs with a narrow absorption window in the upper gastrointestinal tract, high solubility in acidic pH, or instability in alkaline or colonic environments. The formulations employ excipients such as hydrocolloids, polymers, effervescent agents, fatty materials, and release modifiers to maintain buoyancy and regulate drug release. Depending on the design, FDDS may be classified as effervescent, non-effervescent, raft-forming, hydrodynamically balanced, or multi-unit systems. Numerous drugs, including anti-ulcer agents, antibiotics, antihypertensives, and antidiabetics, have been successfully formulated into floating systems. While FDDS provide sustained release, improved bioavailability, and reduced dosing frequency, limitations include dependence on gastric motility, fluid level, and patient variability. Recent advances such as floating microspheres, super-porous hydrogels, and 3D-printed personalized systems highlight the potential of FDDS in modern therapeutics. Future perspectives focus on integrating nanotechnology and smart polymers to further enhance site-specific drug delivery and patient outcomes.