Natural Polymer-Based Gastroretentive Floating-Bioadhesive Matrix Tablets of Furosemide: Formulation, Optimization, and in Vitro Evaluation

Abstract

Background: Furosemide exhibits low and variable oral bioavailability owing to its limited absorption window in the upper gastrointestinal tract, short gastric residence time, and poor aqueous solubility. The present study aimed to develop and optimize a floating-bioadhesive matrix tablet of furosemide using Delonixregia seed mucilage as a novel natural polymer to enhance gastric retention and sustain drug release.
Methodology: Floating-bioadhesive matrix tablets were prepared by the direct compression method and optimized using a three-factor, three-level Box–Behnken design. Plant mucilage concentration, drug ratio, and effervescent content were selected as independent variables, while floating lag time, total floating time, and cumulative drug release were evaluated as the responses. The optimized formulation was further characterized for physicochemical properties, swelling index, bioadhesive strength, drug content, and in-vitro drug release. Results and
Discussion: The optimized formulation consisted of 4% mucilage, a drug ratio of 1:2, and 10% effervescent content. It exhibited a floating lag time of 53.77 ± 1.35 s, total floating time of 13.83 ± 0.25 h, swelling index of 321.50 ± 2.91%, bioadhesive strength of 27.53 ± 0.75 g, drug content of 99.90 ± 0.70%, and cumulative drug release of 91.07 ± 0.65% over 12 h. The optimized formulation demonstrated excellent buoyancy, effective mucoadhesion, and sustained drug release, confirming the suitability of the optimized polymer matrix for gastroretentive delivery.
Conclusion: The developed floating-bioadhesive matrix tablets successfully achieved prolonged gastric retention and sustained drug release. Delonixregia seed mucilage proved to be an effective natural polymer for developing gastroretentive delivery systems and represents a promising alternative to conventional synthetic polymers for sustained oral delivery of furosemide.