The Role of Surface Energy and Wettability in Polymer-Based Drug Delivery Systems: Enhancing Bioadhesion and Drug Release Efficiency

Polymer-based drug delivery systems are pivotal in advancing the precision and efficacy of modern therapeutics. Among the key factors influencing these systems, surface energy and wettability are crucial in determining their interaction with biological tissues and drug release behavior. Surface energy, which governs the adhesive properties of the polymers, plays a significant role in bioadhesion-a critical aspect for drug delivery routes that require prolonged contact with biological surfaces, such as mucosal membranes. Wettability, the extent to which a polymer surface can be wetted by biological fluids, influences both drug loading efficiency and release kinetics. Hydrophilic polymers, characterized by high wettability, typically facilitate rapid drug release, whereas hydrophobic polymers, with low wettability, offer controlled, prolonged release profiles. Additionally, the balance between hydrophilicity and hydrophobicity is essential for optimizing drug-polymer interactions, particularly in systems designed for sustained or targeted drug delivery. Advances in surface modification techniques have enabled precise control over these parameters, allowing for the customization of polymers to meet specific therapeutic requirements. This review discusses the interplay between surface energy, wettability, and drug delivery performance, highlighting how these properties have been manipulated to enhance bioadhesion, drug retention, and release profiles. The review also addresses the challenges in designing polymer wettability, such as maintaining stability, scalability, and regulatory compliance. Finally, it explores emerging trends, including stimuli-responsive polymers and nanotechnology integration, which hold promise for the next generation of drug delivery systems that are more efficient, targeted, and patient-specific, than current systems.