A Formulation and Evaluation of Gastro-retentive In-Situ Gel of Anti-Ulcer Drug Misoprostol

Background: Peptic ulcer disease (PUD) is a prevalent gastrointestinal disorder caused by an imbalance between protective and aggressive gastric factors. Misoprostol, a synthetic prostaglandin E1 analogue, is effective in ulcer management but has limitations such as rapid metabolism, low bioavailability, and frequent dosing. This study aimed to develop a gastro-retentive in-situ gel of misoprostol to enhance gastric retention and controlled drug release. Methods: The in-situ gel was formulated using gellan gum and calcium carbonate as key excipients. A 3² factorial design was employed to optimize floating lag time and in-vitro drug release. The formulations were evaluated for pH, viscosity, gelling capacity, floating behavior, drug content, and in-vitro drug release using a USP Type II dissolution apparatus in simulated gastric fluid (pH 1.2). Stability studies were conducted under accelerated conditions (40°C ± 2°C / 75% ± 5% RH) for six months. Results: The optimized formulation (LF5) exhibited a pH of 6.6, a floating lag time of 18.03 seconds, and a total floating time exceeding 6 hours, ensuring prolonged gastric retention. Drug content analysis confirmed 93.04% uniformity across batches. In-vitro drug release showed sustained drug release of 93.04% over 240 minutes. Stability studies demonstrated no significant changes in pH, floating behavior, or drug content, confirming formulation robustness. Conclusion: The gastro-retentive in-situ gel of misoprostol successfully enhanced gastric retention and controlled drug release. The optimized formulation exhibited rapid buoyancy, prolonged retention, and stability, making it a promising approach for improving misoprostol’s therapeutic efficacy in peptic ulcer management.