The applicant firm will demonstrate feasibility of their non-invasive continuous skin Patch to monitor the use of opiates. Research efforts in Phase I will be directed at confirming that the sweat collection Patch as designed will collect an amount of codeine that correlates quantitatively to the dose consumed both within a single subject and between a group of ten subjects. This investigation will also confirm that valuable diagnostic information can be gained by continuous monitoring by way of a skin Patch. Phase I testing on human subjects will gather currently unavailable data on the dynamic availability of opiate to the skin. This will provide a base of knowledge from which Phase II studies can be developed to extend use of the Patch to other opiates and other drugs of abuse. The need for non-invasive lower-cost drug testing methods is widespread throughout the population. In particular, this device can be useful in rehabilitation programs, penal institutions, public out-patient programs. The Patch can also be used as a tool to measure compliance to and efficacy of candidate medications for treatment of addiction.