Formulation and optimization of gastroretentive tablets containing famotidine in combination with antacids: In vitro...

Famotidine (FMD) is a histamine H₂-receptor antagonist frequently co-administered with antacids to accomplish synergistic effects. It exhibits a rapid onset of action, limited bioavailability, and a short half-life. Effervescent floating tablets (EFTs) are low-density gastroretentive formulations designed to overcome the limited bioavailability of drugs. This study aims to develop single-layer EFTs to provide sustained drug release and prolonged gastric residence time. The EFTs were formulated for FMD in combination with calcium carbonate and aluminum hydroxide as antacids using the direct compression technique. The study investigated the effects of varying ratios of guar gum, hydroxypropyl methylcellulose (HPMC), and polyvinylpyrrolidone (PVP) on parameters including hardness, friability, floating lag time, dissolution efficiency (DE), and cumulative drug release after 8 h. The optimized EFTs formulation was composed of 14.74% w/w guar gum, 7% w/w HPMC, and 15% w/w PVP. It demonstrated a hardness of 54.28 N, friability of 0.74%, a floating lag time of 40.69 min, a DE of 53.25%, and a cumulative drug release of 84.64%. The results closely aligned with the predicted values of 55.2 N, 0.72%, 32.12 min, 59.87%, and 87.8%, respectively. Furthermore, the optimized EFTs formulation remained stable under accelerated stability conditions for 6 months and provided sustained drug release compared with commercial tablets, which released their contents within 30 min.