Formulation and Evaluation of Metformin Gastroretentive Drug Delivery System

Metformin, a first-line oral medication for Type 2 Diabetes Mellitus, faces challenges like low bioavailability (~50-60%) due to its limited absorption in the upper gastrointestinal tract and rapid intestinal transit. To address these issues, a gastroretentive drug delivery system (GRDDS) was formulated using floating drug delivery system (FDDS) technology. The goal was to enhance bioavailability, prolong gastric retention, and offer sustained drug release. Hydrophilic polymers like Hydroxypropyl Methylcellulose (HPMC K4M) were used in combination with gas-generating agents (sodium bicarbonate and citric acid) to create tablets that float in gastric fluids. Five formulations (F1-F5) were prepared and evaluated for pre-compression parameters, tablet hardness, floating lag time, total floating duration, swelling index, and in vitro drug release. Among these, F2 showed optimal characteristics, including rapid buoyancy (1.5 min), extended floating duration (>12 hours), and controlled drug release (88.2% over 12 hours). The study concluded that the floating metformin tablets offer a promising approach to improving therapeutic efficacy, patient compliance, and treatment outcomes for diabetes management by maintaining the drug in the stomach for an extended period.