Exploring lecithin's structural diversity to control core crystallinity in poly (ethylene oxide)-b-poly(ε-caprolactone) nanocarriers

Incorporating advances in biodegradable polymers and colloidal science, this study specifically examines the impact of symmetric and asymmetric lecithin-based additives on the core crystallinity of micelle- and emulsion- based drug delivery carriers made from poly(ethylene oxide)-b-poly(epsilon-caprolactone). Core crystallinity was characterized using 1 H T2 relaxation measurements, which revealed that nanocarriers containing 10 % symmetric lecithin exhibited optimal rigidity, while those with 7.5 % asymmetric lecithin achieved maximal flexibility. Temperature-dependent T2 relaxation analyses demonstrated distinct thermodynamic behaviors, with asymmetric lecithin enhancing core flexibility and increasing thermo-sensitivity by 12.5 % compared to symmetric lecithin. Furthermore, skin permeability studies indicated that emulsions with 7.5 % asymmetric lecithin demonstrated significantly improved absorption capacity and diffusion rates relative to their 10 % symmetric counterparts. These results elucidate the critical role of lecithin structure and concentration in modulating the physicochemical properties of nanocarriers, providing a robust framework for the rational design of advanced drug delivery systems tailored to specific therapeutic requirements.