Opening Avenues for Rheumatoid Arthritis Treatment via Transdermal Application of Microneedles: Progress so far and Future Outlook.

Rheumatoid arthritis (RA) is a chronic autoimmune disease with a global prevalence of 0.5% to 2%, causing serious impairment and early mortality. Presently approved therapeutics comprising non-steroidal anti-inflammatory drugs (NSAIDs), disease-modifying anti-rheumatic drugs (DMARDs), corticosteroids, etc. only lower pain, edema, and inflammation. Most of these therapeutics have been administered orally, intravenously, and intra-articularly, minimizing patient adherence. Additionally, high doses of these drugs need to be taken for a long duration and have poor specificity, causing fatal side effects. The conventional and nanocarrier (NCs)-based topical cargo delivery pose challenges like poor residence, possibility of skin reactions, and low patient adherence. Therefore, transdermal delivery of these therapeutics using microneedles (MNs) can be promising to improve permeability, bioavailability, targeting, and patient compliance while minimizing side effects. Moreover, NCs-assisted MNs, biomimetic NCs-based MNs, and MNs for biologics delivery have also emerged as a promising platform for targeting RA efficiently. This review attempts to give an overview on the transdermal drug delivery using MNs and NCs-based MNs in the efficient management of RA. Thus, different MNs and their amalgamation with NCs could effectively deliver and manage RA via the transdermal route.