A Stimuli-Responsive Hybrid Platform for the On-Demand Delivery of Vitamin B12

Physically triggered drug release is an emerging field focused on developing materials capable of modulating release kinetics in response to external stimuli. In this work, we present a strategy for the fabrication and evaluation of heat-mediated drug release from electrospun fibers composed of a polyacrylonitrile (PAN) and poly (methyl vinyl ether-alt-maleic acid) (PMA-MVE) blend, encapsulating vitamin B12 (B12-NFs) as a model. Following thermal treatments at 90, 120, and 180 °C, results from SEM, TGA, DSC, and FTIR confirmed that increasing the crosslinking temperature promoted the formation of a more hydrophobic matrix (contact angle > 150°), which effectively reduced spontaneous drug leakage. As a proof-of-concept, we evaluated the sensitivity of the elaborated B12 to heating in aqueous media using UV-Vis spectrometry. The results indicate that the release kinetics followed a sigmoidal profile governed by the dissolution Gompertz model. This laboratory-scale evaluation establishes the fundamental mechanisms for magnetically triggered platforms based on polymeric blends, providing a robust framework for the design of remotely activated, non-invasive drug delivery platforms.