Nanoformulation-assisted microneedle transdermal drug delivery system: An innovative platform enhancing rheumatoid arthritis treatment

A transdermal delivery system offers high bioavailability and favorable patient adherence, constituting an optimal approach for localized administration in rheumatoid arthritis (RA) treatment. However, the stratum corneum (SC) impedes the delivery efficiency of conventional transdermal drug delivery systems. Microneedles (MNs) can temporarily create micropores within the SC, enabling drug distribution via bypassing this barrier and enhancing transdermal delivery effectiveness. Notably, MNs provide a painless method of drug delivery through the skin and may directly modulate inflammation in immune cells by delivering drugs via the lymphatic system during transdermal administration. However, the MN delivery system is not suitable for drugs with low water solubility and stability. Additionally, major concerns exist regarding the safety of using MN delivery for highly cytotoxic drugs, given that it could result in high local drug concentration at the delivery site. While MNs exhibit some degree of targeted delivery to the immune and inflammatory environment, their targeting efficiency remains suboptimal. Nanoformulations have the potential to significantly address the limitations of MNs in RA treatment by improving drug targeting, solubility, stability, and biocompatibility. Therefore, this review provides a concise overview of the advantages, disadvantages, and mechanisms of different types of MNs for RA treatment. It specifically focuses on the application and advantages of combining nanoformulation with MNs for RA treatment and summarizes the current trends in the development of nanoformulations combined with MNs in the field of RA treatment, offering theoretical support for future advancements and clinical applications.