Development and optimization of polymeric nanosponges for enhanced delivery of diflunisal in rheumatoid arthritis

Rheumatoid arthritis damages the synovial membrane, and diflunisal, a nonsteroidal anti-inflammatory drug (NSAID) with poor solubility, faces delivery challenges. Nanosponges enhance diflunisals solubility improving its bioavailability; in addition it improved its stability and controls its release. Current research focuses on developing polymeric nanosponges (DIF-NS) through emulsion solvent evaporation, optimized by central composite design. The optimized DIF-NS were further loaded into a carbopol 940 gel (DIF-NS-gel) and evaluated. The optimized BNS showed spherical morphology, % CDR (Percentage cumulative drug release) of 84.9 ± 1.6 within 12 hours and % entrapment efficiency of 82.45 % ± 1.2, a % practical yield of 75 % ± 2.2 with a particle size of 120.1 ± 8.5 nm, zeta potential -29 ± 3.2 mv, and a PDI of 0.348± 0.015. The drug excipient compatibility study was carried out by using FTIR. The sharp peak obtained in the DSC and XRD proves the drug's crystalline nature. The DIF-NS-gel exhibited sustained release and enhanced ex-vivo permeation compared to plain diflunisal gel. In a CFA-induced rheumatoid arthritis rabbit model, it significantly reduced inflammation for a prolonged duration. These findings highlight its potential for effective long-term rheumatoid arthritis management.