Objectives: A tearable dissolving microneedle system (TD-MN system) was developed for shortening the time required to administer drugs into the skin through the dissolving microneedles.
Methods: TD-MN system consisted of an array of tearable dissolving microneedles (TD-MN) and micro-pillars. The microneedle tips had a female part to integrate with the micro-pillars. The micro-pillars exerted a vertical force to cause the separation of the tips from the base. The separation force exerted by six TD-MN arrays with different thicknesses of separation region was measured. The TD-MN system with trypan blue was inserted into porcine skin to observe the separation of the microneedle tips, and then calcein was added separately to observe drug diffusion into the skin.
Results: The thickness of the tearable region and the depth of the female part were a function of the concentration and volume of the molding solution. The separation force increased as the thickness of the tearable region increased. Nine tips were successfully separated from the base by applying a force of through the micro-pillars.
Conclusions: The TD-MN system could provide immediate administration of a drug, resulting in improved patient convenience as well as delivery of the correct drug dose.
Keywords: Tearable dissolving microneedles; conventional manufacturing process; micro-pillars; rapid separation; shortened application time.