Structural modification and biofunctional evaluation of finger millet starch films for topical delivery of ferulic acid.

This study reports the formulation and biofunctional evaluation of ferulic acid (FA)-loaded films using native (NFS) and carboxymethylated (MFS) finger millet starch for advanced wound management. Successful structural modification (degree of substitution: 0.17 ± 0.05) was confirmed via 1H NMR, ATR-FTIR, and CHN elemental analysis. X-ray diffraction revealed a reduction in relative crystallinity (25.5% to 21%) following etherification, while thermogravimetric analysis (TGA) demonstrated a structural degradation shift (Tmax) from 302 °C to 228 °C indicated thermal stability exceeding 150 °C. Compared to the native matrix, MFS exhibited superior solubility, bioadhesion, and prolonged matrix integrity during extended 6-h swelling studies. Crucially, kinetic modeling of in-vitro dissolution profiles revealed that optimized 10% FA-loaded MFS films provided highly sustained drug release governed by Super Case-II transport (Korsmeyer-Peppas, n = 1.20). This robust, crosslinked hydrogel network successfully suppressed the rapid burst release and anomalous matrix erosion (n = 0.81) observed in unmodified native films. In-vivo excision wound models demonstrated that 10% MFSFA films significantly accelerated healing, achieving 97.06% wound contraction by day 12. Histopathological and biochemical evaluations confirmed advanced epithelial regeneration, restored dermal appendages, and elevated hydroxyproline deposition (5.06 mg/g) comparable to standard povidone‑iodine treatment. These findings establish chemically modified finger millet starch as a highly stable, structurally tunable biopolymer platform for the sustained topical delivery of antioxidant therapeutics.