Description

The investigator will conduct a non-randomized, non-blinded, feasibility study at a single center in the United States. The study will include up to 20 subjects of an equal number of male and female adults (ages 18-70) who have a prescription for methadone for chronic pain. In Aim 1, the investigator will determine if an RMM can assess the status of taking a prescribed dose of methadone, using biosamples (i.e., ISF, blood) collected from subjects and tested in a laboratory setup. Biosample collections and pharmacokinetic monitoring will take up to 6 consecutive hours. By completing this aim, the investigator will determine if a physician is able to recognize the peak and trough of a methadone dose using ex vivo Differential Pulse Voltammetry (DPV).

In Aim 2, the investigator will determine if an RMM can continuously assess the status of taking a prescribed dose of methadone over time, by inserting the intradermal microneedle sensing elements into the subjects' skin. The electronics for the RMM prototypes will consist of commercially available benchtop potentiostats like the PalmSens Sensit BT (https://www.palmsens.com/product/palmsens4/) or CH Instruments 660D (https://www.chinstruments.com/) and will not be in direct contact with the skin. Biosample collections (i.e., ISF, blood) and pharmacokinetic monitoring will occur over a 6-hour period. By completing this aim, the investigator will determine if a physician is able to recognize the pharmacokinetic profile of a taken dose of methadone. The physician will see a dosing curve display generated from intradermal microneedle sensing elements that are worn continuously on the skin. Completion of Aims 1-2 will require two separate visits.