A device for delivering a drug includes a body having a proximal end and a distal end and an opening in the distal end thereof. The end point of the travel road is defined as a reference end point, the travel road is defined as a reference road, and the first road is defined as a determination target road. The compounds are effective in, among other things, reducing the effects of aging, photoaging, and skin atrophy, including skin atrophy resulting from the topical use of retinoids andor steroids. The chunks are combined when the data object is subsequently accessed, and a signature is generated for the reassembled data object. Also provided is a method of testing a surface with such an apparatus.