Asian Journal of Microbiology and Biotechnology

Peptic ulcer therapy with esomeprazole may be limited by acid sensitivity, a short plasma half-life, and inadequate gastric residence of conventional dosage forms. This study aimed to formulate and evaluate a gastroretentive in situ hydrogel of esomeprazole using sodium alginate and chitosan. Four formulations (F1–F4) were prepared through ion-mediated gelation according to a 2² factorial design, with HPMC, sodium citrate, calcium carbonate, sodium bicarbonate, and methyl paraben as formulation components. Pre-formulation testing included organoleptic evaluation, melting point, absorption maximum, FT-IR analysis, solubility, and partition coefficient. The formulations were assessed for appearance, pH, viscosity, floating lag time, floating duration, gelling capacity, swelling, spreadability, drug content, and in vitro drug release in acidic medium. Esomeprazole showed a melting range of 185–187 °C, an absorption maximum of 301 nm, and a log P of 0.93 ± 0.05. Among the formulations, F2 provided the most balanced performance, with a pH of 6.36, solution viscosity of 320 cP, gel viscosity of 6,800 cP, gelling time of 14 seconds, floating lag time of 65 seconds, floating duration exceeding 24 hours, spreadability of 30.61 g·cm/s, and drug content of 99%. F2 released 77.5% of the drug over 6 hours. The findings indicate that F2 formed a buoyant and structurally stable matrix capable of sustaining esomeprazole release in vitro. Further stability and in vivo studies are required before therapeutic performance can be established.