Formulation and in-vitro characterization of okra mucilage-based controlled release hydrogels

Background: Certain drugs at therapeutic doses can cause gastrointestinal toxicity, which controlled-release formulations help to address. Natural polymers are widely used in drug delivery due to their non-toxic, biodegradable, and biocompatible properties. Okra mucilage powder (OMP) is especially promising because of its strong gelling ability and pH-sensitive behavior. Objectives: This study aimed to develop OMP-based hydrogels for the controlled release of methotrexate (MTX) over extended periods via free-radical polymerization. Methods: Acrylic acid (AA) was used as the monomer with OMP and gelatin as polymers, N, N-methylene bis-acrylamide (MBA) as the crosslinker, and ammonium persulfate (APS) as the initiator. SEM analysis revealed a porous, rough structure that facilitates MTX loading. Thermal stability and chemical compatibility were confirmed by TGA and FTIR analyses. Results: The hydrogels exhibited pH-dependent swelling, with the highest at pH 7.4 and the lowest at pH 1.2. Formulation OG3 with increased gelatin (1.6%) and MBA (0.6%) showed the best stability and controlled release (r²=0.996). Conclusion: Drug release followed the Korsmeyer-Peppas model (r²?0.996), demonstrating successful development of stable, pH-responsive hydrogels for MTX delivery.