Rapid dissolution microneedle based on polyvinyl alcohol/chitosan for local oral anesthesia

At present, the main clinical methods of oral local anesthesia are direct injection of anesthetic and surface ointment. However, the pain and fear caused by the injection, the discomfort of topical anesthetic creams, and the scour and moist oral environment during the procedure pose great challenges to oral anesthesia. Herein, we designed a Lido-PVP/PVA DMNP microneedle (MN) for oral local anesthesia. The microneedle tip was consisted of Polyvinylpyrrolidone/Polyvinyl alcohol (PVP/PVA), which can quickly dissolve and release the lidocaine hydrochloride (Lido) drug within 5 min to achieve rapid anesthesia. The backing was composed of polyvinyl alcohol/chitosan (PVA/CS), and its excellent adhesion can overcome saliva erosion and anchor firmly to the oral mucosa, significantly improving the utilization rate of drugs, as well as the patient compliance. MNs have good mechanical properties for tissue insertion while possessing high drug loading (3 mg/MNs). Von Frey tests proved that MNs showed a faster and more effective local anesthetic effect (anesthesia takes effect at 5 min) compared to cream (anesthesia takes effect at 30 min). In addition, the excellent biocompatibility and no skin irritation endowed Lido-PVP/PVA DMNP MNs a great potential for oral local anesthesia in the oral cavity.