Design and Optimization of Controlled Release Bilayer Floating Tablets of Famotidine Using HPMC Polymers
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Abstract
The present study focuses on the formulation and evaluation of bilayer floating tablets of famotidine, a histamine H₂-receptor
antagonist widely used to manage acid-related gastrointestinal disorders. Due to famotidine’s short biological half-life and
limited bioavailability, a gastro-retentive bilayer system was developed to enhance its residence time in the stomach and
provide sustained drug release. The formulation comprised a controlled-release (CR) layer containing famotidine and
matrix-forming polymers like HPMC K15M, K100M, and calcium CMC, and an effervescent layer composed of sodium
bicarbonate and citric acid to facilitate gastric buoyancy. Preformulation studies, including FTIR and DSC, confirmed the
compatibility of the drug with selected excipients. The micrometric properties of both the drug and tablet blend indicated
good flow characteristics, suitable for direct compression. The tablets were evaluated for physical parameters such as
hardness, friability, weight variation, buoyancy lag time, and drug content, all of which were within acceptable limits. In vitro,
drug release studies over 24 hours revealed a sustained release profile across all formulations, with F1 and F2 showing
>100% release and F3 showing the most controlled profile (90. 4%). Drug release kinetics best fitted the first-order model
(R² > 0.95) for most formulations, and the Higuchi model (R² = 0.875–0.922) confirmed diffusion-based release. The
Hixson–Crowell model was less suitable. These results confirm the potential of bilayer floating tablets for improved bioavailability
and patient compliance.