Highly\nWater-Soluble Microneedle Patch for Short Wear\nTime and Rapid Drug Delivery

Treatment of acute medical conditions such as pain would\nbenefit\nfrom rapid drug delivery and improved ease of administration of local\nanesthetics that currently have a slow onset of action by topical\nor oral administration and require expert administration by injection.\nTo address this need, microneedle (MN) patches containing needlelike\nprojections made from a polymer/drug matrix can be painlessly pressed\ninto the skin for local or systemic drug delivery. To improve the\nspeed and ease of drug delivery, we present a rapidly dissolving,\nhighly water-soluble MN patch, which minimizes the wear time to 10\ns to improve drug delivery in situations where rapid delivery with\nsimplified administration is needed. MNs were made of polyvinylpyrrolidone\n(PVP), which is soluble in both water (enabling dissolution in the\nskin) and polar organic solvents (facilitating coformulation with\nlidocaine (L)). The addition of a highly water-soluble salt, sodium\nbicarbonate (NaB), to PVP/L MNs allowed for 60% faster MN dissolution\nin porcine skin ex vivo. Further addition of citric acid to generate\neffervescence upon reaction with NaB did not further decrease the\nMN dissolution time in the pig skin and led to poor shelf-life stability\ndue to premature effervescence during storage. The PVP/L/NaB MNs delivered\n23.8 ± 3.5 μg lidocaine to the skin ex vivo, well above\nthe expected dose for local analgesic effect. Our highly water-soluble\nPVP/L/NaB MN design enables shorter wear time for faster delivery\ncompared to the oral or topical route and easier administration compared\nto injection currently used for the delivery of drugs needing a rapid\nonset of action.