Alkalizer-based gastroretentive floating tablets of amoxicillin for localized gastric delivery

Helicobacter pylori infection is a leading cause of peptic ulcer disease, yet amoxicillin trihydrate (AMX) efficacy is limited by its acid-catalyzed degradation and rapid gastric emptying. This study aimed to develop alkalizer-based gastroretentive floating tablets to enhance localized gastric-delivery and improve AMX stability under gastric conditions.

Floating tablets were prepared by direct compression using HPMC K100M, sodium-bicarbonate and microcrystalline-cellulose. A 2³ factorial-design (RStudio-v4.3.3) was used to optimize microenvironmental pH, floating lag time (FLT) and drug release. Optimized tablets were characterized for micromeritic properties, XRD, SEM, in vitro buoyancy, swelling, drug release, in vitro anti-H. pylori activity and in vivo gastric retention in Sprague-Dawley rats.

The optimized formulation achieved a microenvironmental pH of 7.20 ± 0.26, FLT of 15.84 ± 0.50 s, and total floating time of approximately 12 h. Cumulative AMX release reached 98.49 ± 1.69% over 12 h with non-Fickian kinetics, and XRD/SEM analysis indicated reduced crystallinity and increased amorphous character of AMX within the hydrated matrix. The formulation showed significant in vitro anti-H. pylori activity and prolonged in vivo gastric retention.

Alkalizer-based gastroretentive floating AMX tablets combined microenvironmental pH modulation with sustained gastric-retention, supporting their potential as a localized strategy for improved H. pylori eradication.