Drug release profile of phenytoin-loaded starch-based biomaterials incorporating hierarchical microparticles with photothermal effects

This study aimed to synthesize phenytoin (PHT)-loaded water chestnut starch-based biomaterials and evaluate their drug release kinetics for use in transdermal drug delivery systems for antiepileptic therapy. Hierarchical microparticles (HMPs) extracted from human hair were also used to improve the PHT release efficiency. The physicochemical characteristics of PHT, HMPs, and the prepared biomaterials were evaluated by physical properties, antimicrobial activities, FE-SEM, FT-IR, XRD, ¹H NMR, and ¹³C CPMAS solid-state NMR. The photothermal effect and the PHT release profile were confirmed through 808 nm NIR laser irradiation. After 30 min of the laser exposure, the temperature of the HMP-added biomaterials increased by 1.50-1.59 times compared to that of without the HMPs. PHT release in buffers and artificial skin test under NIR laser irradiation enhanced by 1.20-1.85 times owing to the photothermal effect. The release kinetics in pH buffer and artificial skin were determined using the Fickian diffusion and Korsmeyer-Peppas models. Additionally, to verify the transdermal penetration of PHT, drug-release simulations were conducted using rhodamine B in agar blocks and pig ears. The results implied that the photothermal effect of the HMPs enhanced the penetration of the drug.