Highly absorbent and mechanically robust composite films were developed by blending deproteinized natural rubber (DPNR) with either sodium alginate (SA) or SA esterified with hydroxypropyl methylcellulose (HPMC). Esterification of SA was shown to promote its uniform dispersion in DPNR, resulting in enhanced mechanical integrity and improved interfacial adhesion within the composite films. Composite films containing 40% (w w −1 ) esterified SA (designated as FSAE films) exhibited rapid buffer uptake (∼350% swelling within 1 h), low erosion, and efficient release of the model drugs. Drug release followed Peppas–Sahlin kinetics, indicating contributions from both Fickian diffusion and polymer matrix relaxation. Compared with films prepared using non-esterified SA, the FSAE films released the model drugs more rapidly, mainly because ester hydrolysis and matrix erosion facilitated drug transport. In particular, the FSAE films enabled faster release of both the anionic dye methyl orange (MO) and the poorly water-soluble nonionic dye purpurin (PP), whereas the corresponding films comprised of 40% (w w −1 ) SA showed slower and less extensive release of PP. Thus, the esterified SA phase both accelerated overall release and enhanced the delivery of poorly water-soluble drugs. Biocompatibility assessment via MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay confirmed excellent cytocompatibility of FSAE films with L929 mouse fibroblast-like cells. Overall, the developed FSAE films had good potential as biocompatible and highly absorbent wound dressings with controlled drug-release capability. Furthermore, the esterification-based compatibilization of hydrophilic alginate with hydrophobic natural rubber proved to be a scalable strategy for producing multifunctional rubber-based composites for advanced wound care and related drug-delivery applications. • Highly water absorbent composite films were made using natural rubber. • Hydrophobic rubber and esterified alginate were composited to form the films. • The films absorbed buffer rapidly (∼350% swelling in 1 h) and eroded poorly. • The cytocompatible films were suitable for use as wound dressings. • Drug release from films was driven by both diffusion and polymer relaxation.
Sarilak et al. (2026) studied this question.