Preparation and evaluation of dissolving microneedle loaded with azelaic acid for acne vulgaris therapy

Anti-acne microneedle technology is an emerging approach to acne vulgaris and acne scars therapy. Currently, solid microneedle is the most common one in clinical practices. Nevertheless, it needs to be operated by professionals. Additionally, there is a potential risk of needle breakage, leading to a biohazard inside the skin. This study prepared and evaluated a dissolving microneedle (DMN) containing azelaic acid (AZA), providing a novel self-administered and rapid-onset pathway for acne patients. The AZA-loaded DMN can be inserted into the skin under the loaded force of 5 N. We examined the safety, transdermal release, stability, antibacterial activity, and pharmacokinetic studies of AZA-DMN to provide reference and guarantee for clinical trials. Besides, to evaluate the efficacy of DMN containing AZA, a randomized and controlled pilot study was conducted on adult acne patients. The results indicated that AZA-DMN had good skin compatibility and formulation stability. Furthermore, there was no significant difference in AZA concentrations in rats’ plasma before and after administration, revealing that AZA-DMN mainly worked on local skin. Compared to the control groups, more remarkable inflammation subsidence appeared in the AZA-DMN group. Meanwhile, it was shown that the delivery of AZA using DMN significantly shortened the therapy cycle compared with commercially available AZA cream. In summary, our studies confirmed that AZA-loaded DMN provided a promising treatment strategy for acne patients due to the enhanced transdermal permeability of AZA and its noticeable antibacterial effect on Propionibacterium acnes and Staphylococcus epidermidis.