Transdermal drug delivery (TDD) is an attractive alternative to oral and hypodermic injection drug administration, and is poised to increase its impact on medicine and pharmaceutical design. Microneedles (MNs) are a new minimally invasive TDD method widely used in medicine and cosmetology. MNs create a microscale channel from the stratum corneum to the dermis and enable drug delivery of hydrophilic and macromolecular into the skin. Although MNs allow different drugs to penetrate the stratum corneum, they cannot provide an extra driving force for drug transport in tissue. To overcome this limitation and achieve fast, controllable drug delivery, an integrated 3D-printed ultrasonic MN array (USMA) device consisting of hollow MNs and an ultrasonic transducer is proposed. The hollow MNs enable drug to penetrate the stratum corneum, and the ultrasound transmitted through the MNs provides the driving force for drug transportation in tissue. Using methylene blue and bovine serum albumin as model drugs, we tested the drug delivery performance of USMA on porcine skin; the results show that USMA significantly enhanced the delivery efficiency of model drugs. Besides, USMA obviously reduced MNs insertion force and tissue damage, which were well-tolerated and gentle. This study suggests that the integrated ultrasonic MN array has great potential for clinical drug delivery with high efficiency and lessening the suffering of patients.
Keywords: 3D printing; hollow microneedles; transdermal drug delivery; ultrasound.