Biodegradable Polymeric Core/Shell Nanoformulations Encapsulating Essential Oils: Physicochemical Design, Controlled Release, and Targeted Acne and Sebum Management

This review examines biodegradable polymer-based core–shell nanoformulations encapsulating essential oils for acne treatment through the lens of physicochemical design and controlled delivery mechanisms. Acne is a common inflammatory skin disorder closely associated with sebum overproduction and microbial imbalance, while conventional therapies, although effective, may present long-term side effects. Increasing attention has therefore turned to sustainable dermatological materials derived from eco-friendly polymers combined with naturally active compounds. Recent advances show that core–shell nanostructures fabricated from biodegradable polymers function as physicochemically engineered carriers for volatile essential oils. They enhance their stability and protect them from premature degradation. They also enable controlled release governed by diffusion, polymer relaxation, interfacial interactions, and degradation kinetics. This review highlights how polymer chemistry, interfacial properties, particle morphology, and processing routes determine encapsulation efficiency, release profiles, and skin permeation behaviour. Particular emphasis is placed on structure–property–function relationships, including mass transport phenomena, thermodynamic compatibility between polymers and essential oils, surface charge, wettability, and nanostructure architecture, which collectively influence bioavailability and therapeutic performance. By integrating concepts from polymer physical chemistry, colloid and interface science, and drug delivery kinetics, these sustainable nanoformulations emerge as promising platforms for acne and sebum control. Overall, essential oil-loaded biodegradable polymeric core–shell systems represent a sustainable and scientifically grounded approach to acne management, although further physicochemical characterization, in vivo validation, and consideration of cost, technical challenges, and current limitations are required to support clinical translation.