Advancing transdermal drug delivery systems: breakthrough innovations, comprehensive evaluation approaches for...

To provide a comprehensive overview of recent advancements in transdermal drug delivery systems (TDDSs), with a focus on their design, development, evaluation, and therapeutic importance.

TDDSs offer a noninvasive route of drug administration that bypasses gastrointestinal metabolism, enhances patient compliance, and improves pharmacokinetic profiles. Over the past two decades, their role in controlled drug delivery has increased significantly.

This review traces the evolution of TDDSs from first-generation systems to modern formulations, highlighting key properties such as drug lipophilicity, molecular size, optimal pH, and potential for skin irritation. Major formulation strategies-membrane permeation, matrix diffusion, and microreservoir systems-are discussed. Testing methodologies, including physicochemical characterization, in vitro diffusion studies, and in vivo evaluations, have also been explored. Advancements in TDDSs have led to the development of more effective transdermal patches capable of increasing skin permeability and expanding the range of drugs that can be delivered. Despite limitations such as difficulty in delivering large- or high-dose molecules, TDDSs demonstrate improved therapeutic efficiency and better patient adherence.

TDDSs represent a significant innovation in drug delivery, offering several advantages over conventional routes. The ongoing development of these materials holds promise for broader clinical applications and improved therapeutic outcomes.