A Comprehensive Review on Mucoadhesive In-Situ Gel Drug Delivery Systems

Oral drug delivery is the most preferred route due to its convenience and patient compliance; however, it faces significant limitations such as enzymatic degradation, first-pass metabolism, gastrointestinal toxicity, and short gastric residence time (GRT), particularly for drugs absorbed in the upper gastrointestinal tract. Gastro-retentive drug delivery systems (GRDDS) have emerged as an effective strategy to overcome these challenges by prolonging gastric retention and enabling controlled, site-specific drug release. Among GRDDS, mucoadhesive in-situ gelling systems offer notable advantages by transforming from a liquid to a gel under physiological conditions, thereby enhancing gastric residence time, bioavailability, and therapeutic efficacy. These systems utilize natural or synthetic polymers that adhere to the gastric mucosa and provide sustained drug release while minimizing dosing frequency and systemic side effects. This review highlights the need, mechanisms, polymers, approaches, applications, and evaluation parameters of mucoadhesive in situ gelling systems as promising platforms for advanced gastro-retentive drug delivery.