Enhanced drug release control in coaxial electrospun fibers via heat pressing: Reducing burst release and achieving dual-phase delivery

Abstract

Burst release is a common challenge in drug delivery systems (DDS), potentially leading to subtherapeutic or toxic drug concentrations. Coaxial electrospinning has emerged as a promising technique to address this issue by encapsulating drugs within core-sheath fiber structures, thereby preventing direct exposure of the drug to the environment and ensuring a gradual release profile. However, secondary processing of coaxial electrospun membranes, such as cutting or slicing, can damage the core-sheath structure of fibers, exposing the drug-loaded core and exacerbating burst release. In this study, we applied heat pressing along the intended cutting line prior to cutting, aiming to thermally seal the core-sheath structure of fibers and prevent drug leakage from the core at cut edges. As a result, the heat-pressed group exhibited a significantly reduced initial burst release followed by a more sustained release compared to the control group, which involved no heat pressing before cutting. The release profiles of both groups were well described by the Korsmeyer-Peppas model with n = 0.32 (R² = 0.95) for the control group and n = 0.49 (R² = 0.99) for the heat-pressed group. Notably, the release behavior of the heat-pressed group exhibited a closer approximation (R² = 0.96) to a first-order model compared to the control group (R² = 0.59). Furthermore, we successfully developed a dual-phase DDS by manipulating the ratio of unsealed (fast release) and sealed (slow release) portions of an electrospun membrane. In conclusion, heat pressing presents a simple yet effective strategy for enhancing the performance and reliability of coaxial electrospun DDS, offering potential for broader applications in controlled drug delivery.