Advanced Transdermal Delivery Systems: Techniques to Maximize Skin Penetration and Drug Efficacy

Transdermal drug delivery systems (TDDS) represent a promising non-invasive alternative for medication administration, effectively bypassing gastrointestinal and hepatic metabolism. However, the formidable barrier presented by the skin's stratum corneum continues to challenge drug penetration and permeation efficiency. Recent advancements have focused on enhancing TDDS efficacy through innovative penetration enhancers and novel techniques. Among these, dimethyl sulfoxide (DMSO) and azone have demonstrated potential as traditional penetration enhancers, while fatty acid-based amino acid ionic liquids offer a novel approach to improving drug absorption. Additionally, innovative techniques such as microneedle technologies and ultra-sound-mediated methods have emerged as promising solutions to overcome the inherent challenges associated with transdermal delivery, particularly in bypassing the stratum corneum. This review systematically examines the most recent literature, exploring both established and emerging strategies to improve TDDS performance. Key databases were consulted to identify relevant studies, and data were synthesized to provide a comprehensive understanding of current advancements. Despite the clear advantages of TDDS, including their non-invasive nature and potential for sustained drug release, challenges related to limited permeation efficiency and the risk of rapid skin irritation persist. Nevertheless, ongoing research efforts are paving the way for the development of more effective and patient-friendly transdermal systems, which hold promise for the future of therapeutic administration through the skin.