STIMULI-RESPONSIVE NANOSPONGE SYSTEM FOR ANTI DIABETIC THERAPHY

The present study was undertaken to develop and evaluate a pH-responsive nanosponge system of Metformin HCl for controlled and site-specific drug delivery. Nanosponges were prepared by the emulsion solvent diffusion method using Ethyl Cellulose as the polymer and Polyvinyl Alcohol (PVA) as the stabilizer. The prepared nanosponges were subsequently modified with Polyacrylic Acid (PAA) to impart pH-responsive drug-release characteristics. Different formulations (F1–F6) were prepared by varying the polymer concentration and evaluated for production yield, drug entrapment efficiency, drug content, particle size, FT-IR, DSC, SEM, and in-vitro drug release. The production yield of the formulations ranged from 79.81% to 84.25%, while drug entrapment efficiency ranged from 78.15% to 92.89%. The particle size was found to be in the range of 303–680 nm. FT-IR studies indicated the retention of characteristic functional groups of Metformin HCl and polymers without major chemical interaction, confirming drug–excipient compatibility. SEM analysis demonstrated the porous nature of the prepared nanosponges. The optimized formulation exhibited pH-dependent drug release, showing relatively low release at acidic pH 1.2 and 4.4, with cumulative drug release of 28.30% and 32.96%, respectively, after 24 h. In contrast, considerably higher drug release of 76.24% was observed at pH 6.8 after 24 h, indicating enhanced release under intestinal pH conditions. The optimized nanosponge formulation demonstrated sustained and pH-responsive drug release and followed predominantly zero-order kinetics. The findings suggest that PAA-coated Metformin HCl nanosponges may provide a promising approach for controlled oral drug delivery with enhanced intestinal drug release.