Hyaluronic acid dissolving microneedle patch-assisted acupoint transdermal delivery of triptolide for effective rheumatoid arthritis treatment

Triptolide (TP), a major active component of the herb Tripterygium wilfordii Hook F, has been shown excellent pharmacological effects on rheumatoid arthritis. However, TP is prone to causing severe organ toxicity, which limits its clinical application. In recent years, microneedle technology has provided a new option for the treatment of arthritis due to its advantages of efficient local transdermal drug delivery. In this study, we constructed a microneedle platform to deliver TP locally to the joints, thereby enhancing TP penetration and reducing systemic toxicity. Additionally, we investigated whether acupoint drug delivery can produce a synergistic effect of needles and drugs. First, TP was loaded into microneedles using polyvinylpyrrolidone and hyaluronic acid as matrix materials. Next, we established a rat adjuvant-induced arthritis (AIA) model to evaluate the therapeutic effect of TP-loaded microneedles. The experiments showed that TP-loaded microneedles alleviated the AIA rats' inflammatory response, joint swelling, and bone erosion. However, there was no significant difference in the therapeutic effect observed in the acupoint and non-acupoint administration groups. In conclusion, TP-loaded microneedles have the advantages of safety, convenience, and high efficacy over conventional administration routes, laying a foundation for the transdermal drug delivery system-based treatment of rheumatoid arthritis.