Multidrug dissolvable microneedle patch for the treatment of recurrent oral ulcer

Recurrent oral ulcer is a painful oral mucosal disorder that affects 20% of the world’s population. The lack of a radical cure due to its unknown underlying cause calls for innovative symptomatic treatments. This work reports a hyaluronic acid-based dissolvable microneedle patch (ROUMN patch, short for recurrent oral ulcer microneedle) loaded with dexamethasone acetate, vitamin C and tetracaine hydrochloride for the treatment of recurrent oral ulcers. The ROUMN patch shows enhancement in both the anti-inflammatory effect elicited by dexamethasone and the pro-proliferation effect of vitamin C. In vitro experiments show that ROUMN has a higher efficiency in suppressing lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) expression than dexamethasone alone. Cell proliferation and migration were also significantly promoted by ROUMN compared to vitamin C alone. The healing-promoting effect of ROUMN was also verified in vivo using an acetic acid-cauterized oral ulcer model in rats. ROUMN as a treatment accelerated the healing process of oral ulcers, shortening the total healing time to 5 days compared with the 7 days required by treatment using watermelon frost, a commonly used over-the-counter (OTC) drug for oral ulcers. The rapid dissolution of the hyaluronic acid-based microneedles and the superior healing-promoting effect of the drug combination could lead to a broad application prospect of the ROUMN patch in the treatment of recurrent oral ulcers. Graphic abstract