Touch-actuated transdermal delivery patch for quantitative skin permeation control

With increasing demands on drug delivery via a transdermal route, there is a therapeutic and regulatory need for on-demand dosage control. Ideally, on-demand dose control would be based on a low-cost, scalable mechanical mechanism without the requirement for ancillary equipment. In this study, we report a touch-actuated transdermal delivery (TATD) patch which provides quantitative permeation control by the degree of mechanical pressing. The patch contains a refillable drug solution reservoir, strain sensor, and drug chamber with an array of microneedles. Mathematical functions are used to predict the normal force applied to the drug reservoir, drug solution released into the drug chamber, and amount of the permeated drug. The final relationship between permeation level and normal force is expressed as a simple equation, which allows for the precise control of drug permeation via external mechanical stimulation. This relationship is demonstrated by image analysis of the permeated drug through animal skin tissue. The TATD patch offers a suitable platform for on-demand control of therapeutic delivery in wearable healthcare systems.