Latch Applicator for Efficient Delivery of Dissolving Microneedles Based on Rapid Release of Elastic Strain Energy by Thumb Force

Abstract

Dissolving microneedle (DMN) is an attractive alternative to parenteral and enteral drug administration owing to its painless self‐administration and safety due to non‐generation of medical waste. For reproducible and efficient DMN administration, various DMN application methods, such as weights, springs, and electromagnetic devices, have been studied. However, these applicators have complex structures that are complicated to use and high production costs. In this study, a latch applicator that consists of only simple plastic parts and operates via thumb force without any external complex device is developed. Protrusion‐shaped latches and impact distances are designed to accumulate thumb force energy through elastic deformation and to control impact velocity. The optimized latch applicator with a pressing force of 25 N and an impact velocity of 5.9 m s−1 fully inserts the drug‐loaded tip of the two‐layered DMN into the skin. In an ovalbumin immunization test, DMN with the latch applicator shows a significantly higher IgG antibody production rate than that of intramuscular injection. The latch applicator, which provides effective DMN insertion and a competitive price compared with conventional syringes, has great potential to improve delivery of drugs, including vaccines.

Egg microneedles for transdermal vaccination of inactivated influenza virus

“…32 For efficient insertion of the EMN, we used a homemade latch applicator that can achieve the optimum pressing force and impact velocity using only the thumb force. 33 In the next section, we described the formulation screening results of the yolk layer for maintaining the activity of the influenza vaccine mounted on the EMN that is critical for the successful vaccination.…”

Novel biotagging method using dissolvable microneedle arrays for individual identification of animals

“…Concerning the misalignment and distortion of character patterns, the slipping of MAPs or skin, which may occur during application, contributes to the misalignment of patterns, including tilted, moved, distorted, or stretched patterns. We considered that a xing device, such as an applicator 32 , can be helpful to x the MAP or skin stably during its application, resulting in patterns without any shape deformations.…”

Mechanical Characterization of Dissolving Microneedles: Factors Affecting Physical Strength of Needles

“…Clinically, dissolving MNs would be applied to the skin using an applicator to improve skin puncturability [ 50 , 51 ]. Recently, we observed that needles with a small base diameter broke near the base without bending tips during skin insertion, which was confirmed by micro-CT imaging.…”