In Situ Floating Gel Systems: Sophisticated Approaches for Gastro-Retentive and Controlled Drug Administration

This article provides an in-depth overview of in situ floating gel systems designed for advanced gastro-retentive drug delivery. These systems begin as liquids that transform into gels upon contact with physiological triggers such as changes in stomach pH, temperature, or ionic strength, leading to sustained, site-specific drug release. Their buoyancy in gastric fluids allows for prolonged stomach retention, making them especially valuable for drugs with absorption limitations or instability in the intestines. The review covers the use of various biopolymers such as gellan gum, sodium alginate, and pectin, as well as synthetic polymers like Carbopol and hydroxypropyl methylcellulose (HPMC), examining their roles in gelation, mechanical strength, and the regulation of both buoyancy and drug release. Key gelation mechanisms, including pH sensitivity, temperature responsiveness, and ion activation, are discussed along with vital formulation techniques and process variables for ensuring optimal performance. The document addresses practices for incorporating drugs and excipients and outlines methods for evaluating physicochemical properties, muco-adhesion, gastric retention, and drug release profiles in vitro. A range of clinical applications is highlighted, such as the gastric delivery of anti-ulcer, antihypertensive, and antibiotic medications, supported by practical case studies. Additionally, the review discusses challenges like formulation stability, reproducibility, industrial scaling, and regulatory matters. It also examines recent progress in stimulus-responsive smart gels and combinatorial delivery approaches. In summary, in situ floating gel systems are presented as innovative solutions for achieving extended, controlled drug release with improved patient adherence, and the text outlines both current approaches and emerging directions for research and therapeutic application in this dynamic field.