The
pain and fear caused by direct local injection of
anesthetic or the poor experience with surface
anesthetic cream increase the difficulty of clinical treatment for oral diseases. To address this problem, a
hyaluronic acid microneedle patch (Li-HAMNs) that consists of fast-dissolving
lidocaine hydrochloride (LDC)-loaded
tips and a wet-adhesive backing layer made of
polyvinyl alcohol (PVA)/
carboxymethylcellulose sodium (CMC-Na) was fabricated to explore its potential use in dental topical
anesthesia. Li-HAMNs could
puncture the stratum corneum with an insertion depth of about 279 μm in the isolated porcine oral mucosal. The fast-dissolving
tips could release LDC to improve the patients' convenience and compliance. Importantly, the backing layer, which has good adhesion ability and water-absorbing properties, could surmount the contraction and extension of oral masticatory muscles and the saliva scour. In the tail flick test, the topical
anesthesia efficacy of the Li-HAMNs group was much better than clinical
lidocaine cream (
EMLA cream, LDC, 1.2 mg) in spite of a relatively lower LDC dose with Li-HAMNs (LDC, 0.5 mg). It is believed that the proposed adhesive microneedle patch could enhance transmucosal delivery of
anesthetics and thus open a new chapter in the painless treatment of oral diseases.