Dissolving microneedles: A transdermal drug delivery system for the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder that impacts around 1% of the global population. Up to 20% of people become disabled within a year, which has a severely negative impact on their health and quality of life. RA has a complicated pathogenic mechanism, which initially affects small joints and progresses to larger ones over time. It can damage the skin, eyes, heart, kidney, and lung. Oral medications, intra-articular injections, and other treatments are being used; nevertheless, they have drawbacks, including low bioavailability, numerous adverse effects, and poor patient compliance. Dissolving microneedles (DMNs) are a safe and painless method for transdermal drug delivery, achieved through their ability to physically penetrate the epidermal barrier. They enable targeted drug delivery, significantly enhancing the bioavailability of medications and improving patient compliance. DMNs are particularly effective in delivering both lipophilic and high molecular weight biomolecules. The superior bioavailability of DMNs is demonstrated by the fact that low-dose DMN administration can achieve up to 25.8 times higher bioavailability compared to oral administration. This paper provides a comprehensive review of recent advancements in the use of DMNs for RA treatment, encompassing various materials (such as hyaluronic acid, chitosan, etc.), fabrication techniques (such as the two-step casting method, photopolymerization), and performance evaluations (including morphology, mechanical properties, skin penetration capability, solubility, and pharmacodynamics). Additionally, a thorough safety assessment has been conducted, revealing that DMNs cause minimal skin irritation and exhibit low cytotoxicity, ensuring their safety for clinical application. DMNs provide a highly effective and promising alternative to oral and injectable drug delivery systems, offering a novel therapeutic approach for RA patients that significantly improves treatment outcomes and enhances their quality of life.