Formulation and Swelling Evaluation of Starch–Glycerol-Based Biopolymer Films for Potential Wound Dressing Applications

This study investigates the structural behavior and swelling performance of biopolymer films formulated from starch, glycerol, carboxymethylcellulose (CMC), and polymeric β-cyclodextrin (PCD) for potential wound dressing applications. Binary starch–CMC and starch–PCD systems exhibited poor rheological properties, forming highly pasty mixtures in the absence of glycerol. Conversely, glycerol–CMC and glycerol–PCD systems remained excessively fluid, confirming the essential structural role of starch in film formation. Ternary starch–glycerol–CMC formulations enabled the production of stable and functional films, particularly 10A/6G/4CMC and 12A/4G/4CMC, which demonstrated substantial swelling capacities of 140% and 164% at 60 minutes, respectively. Swelling kinetics revealed a rapid initial water uptake within the first 60 minutes, followed by a slower approach toward equilibrium. The ability to incorporate CMC without compromising film integrity was strongly dependent on starch proportion, with instability observed when starch content fell below 10 parts. The introduction of PCD into optimized formulations (10A/6G/1CMC/3PCD and 12A/4G/1CMC/3PCD) resulted in moderate swelling capacities (123% and 136% at 60 minutes), lower than those observed for the corresponding binary and ternary systems. These findings suggest that PCD contributes primarily through its inclusion-complex forming capability rather than by enhancing swelling behavior. Overall, the results highlight the critical importance of the starch–glycerol ratio in achieving structurally stable films and confirm the reinforcing role of CMC, while identifying PCD as a promising component for future development of active wound dressings with controlled drug delivery potential. Keywords: Wound dressings, Starch-based biopolymers, Glycerol, Carboxymethylcellulose (CMC), β‑Cyclodextrin (PCD).