An Overview of Topical Drug Delivery Systems: From Concepts to Practice

Abstract Topical drug delivery systems (TDDS) have emerged as a significant area of interest in pharmaceutical sciences due to their unique advantages, such as bypassing hepatic first-pass metabolism, enabling localized therapy, and reducing systemic side effects. These systems are versatile, encompassing a range of formulations like creams, gels, ointments, and advanced nanotechnology-based carriers. Despite their potential, TDDS faces challenges, including the stratum corneum's formidable barrier and the need for aesthetically pleasing, stable, and effective formulations. This review delves into the evolution of TDDS, highlighting traditional and advanced approaches. Special attention is given to novel systems such as micellar microparticles, nanoemulsions, and nanostructured lipid carriers (NLC). These technologies enhance drug solubility, stability, and skin penetration, significantly improving therapeutic efficacy and patient compliance. Additionally, the role of skin anatomy, physicochemical properties of drugs, and innovative formulation techniques in overcoming the limitations of conventional systems is explored. The review concludes with insights into the clinical implications of these systems and future research directions, emphasizing their potential in developing targeted, efficient, and patient-friendly topical therapies. Keywords Topical Drug Delivery Systems, Skin Penetration, Nanoemulsions, Nanostructured Lipid Carriers, Micellar Microparticles