Transdermal patches have emerged as a promising route for therapeutic delivery. Offering advantages over traditional administration methods, they can bypass hepatic first-pass metabolism and improve the bioavailability of lipophilic drugs. These systems, categorized as transdermal drug delivery systems (TDDS), offer protection against enzymatic degradation and acid-induced decomposition of therapeutic agents. TDDS are particularly advantageous for the sustained delivery of low-molecular-weight drugs over extended durations [1]. These systems also provide ease of self-administration, improved patient adherence, controlled drug release, and the ability to immediately discontinue drug delivery by removing the patches [2]. Moreover, the continuous permeation of the active pharmaceutical ingredient through the skin enables dose reduction, thereby mitigating side effects associated with elevated plasma drug concentrations. However, certain limitations persist, such as challenges in delivering ionic and macromolecular drugs, the potential for skin irritation, and reduced efficacy in patients with compromised peripheral blood circulation.

Several techniques of administering drugs transdermally exist, such as microneedles, hydrogels, and bioadhesive materials. The concept of bioadhesion refers to the prolonged attachment of two materials, wherein at least one is biological in nature [3]. In the context of drug delivery, adhesion can be defined as the ability of a drug delivery system to adhere to a specific biological site, which may include epithelial tissues or mucosal layers covering tissue surfaces. This phenomenon involves the interaction between a natural or synthetic polymer and a biological substrate, facilitating targeted and sustained drug administration [4]. The present review aims to explore the emerging role of bioadhesive polymers used for constructing transdermal patches, with a specific focus on their applications in the management of skin disorders. The review analyzes advancements in the design, material composition, and therapeutic potential, as informed by experimental systems. Based on the recent research developments of bioadhesives for TDDS, we seeks to provide a comprehensive understanding of their significance and future prospects in real-world use.