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

• Published in: European polymer journal 2025-01, Vol.223, p.113652, Article 113652
• Main Authors: Do, Uyen Thi, Song, Minji, Kim, Jiwon, Luu, Quy Son, Nguyen, Quynh Thi, Park, Yeeun, Yang, Seyoung, Choi, Jaehwa, Yun, Seokki, Whiting, Nicholas, Lee, Youngbok
• Format: Article
• Language: English
• Subjects: Amphiphilic block copolymer; Core crystallinity; Lecithin additives; Nuclear magnetic resonance; Spin–spin relaxation
• ISSN: 0014-3057
• DOI: 10.1016/j.eurpolymj.2024.113652

By incorporating symmetric or asymmetric lecithin-based amphiphilic phosphocholines, the flexibility of polymeric micelles and emulsions were modulated. The variations in the dynamic properties of lecithin-incorporated nanocarriers were demonstrated through NMR T2 relaxation time and in vitro skin tests. [Display omitted] •This research examines how structured lecithin affects drug carriers based on PEO-b-PCL.•The lecithin’s association and its structure affect the core crystallinity of the nanocarriers.•The core structure of the polymer-carriers can be understood by T2 NMR analysis.•Flexible drug delivery carrier made with 7.5% asymmetric lecithin had a better skin absorption capacity and diffusion rate than the rigid symmetric lecithin-added emulsion. 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(ɛ-caprolactone). Core crystallinity was characterized using 1H 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.