Designing a unique feedback mechanism for hydrogel-forming microneedle array patches: a concept study

Although microneedle array patch (MAP) technology is reaching ever closer to regulatory approval, it remains imperative
that approaches to further improve patient acceptance are still explored. Addressing this perception, a water-flled reservoir
was incorporated into a hydrogel-forming MAP system to provide a novel feedback mechanism. To confrm successful MAP
skin insertion, the end user would both hear and feel the rupture of the water-flled reservoir. Interestingly, a 50-µL waterflled reservoir ruptured at 30.27±0.39 N, which has previously been shown as the mean application force for MN insertion
in human subjects following appropriate instruction. Importantly, no signifcant diference in % cumulative permeation of
FITC-dextran 10 kDa and fuorescein sodium after 24 h was observed between a 50-µL reservoir and the current method of
application that has been successfully used in both in vitro and in vivo studies (p>0.05). Therefore, as drug delivery was not
afected, this proof-of-concept study has shown that a water-flled reservoir feedback mechanism has the potential to serve
as a viable tool for consistent MAP skin insertion.