Simple, Rapid Spectrophotometric Assay of Dispensed Methadone for Diversion Control.

Abstract

Treatment of opioid use disorder with methadone is highly effective. Methadone is dispensed from opioid treatment programs under regulated circumstances. However, diversion of take-home doses can occur and is difficult to detect. We wanted to test the application of a handheld ultraviolet light absorption spectrometer to detect the concentration of methadone in take-home bottles that were suspected of being altered by the patient. Standardized dilutions of methadone hydrochloride oral concentrate were used to calibrate absorption wavelengths and then compared to take homes from suspected and unsuspected bottles to see if measured concentrations differed from expected doses. Ten standardized "control" doses were analyzed to determine 99% confidence intervals. These were compared to 104 samples "not-of-concern" obtained randomly over a 10-month period. An additional 103 methadone bottles of concern from 27 patients showed 15 bottles with <25 % and 8 with <75 % of expected concentrations. A handheld, low-cost ultraviolet light spectrometer detected altered take-home doses of methadone. This assay presents a simple and effective method for methadone clinics to perform inhouse analysis on "call back" methadone doses. It allows individual clinics to define diversion rates of their patient body, while allowing state and federal agencies to better understand how much prescribed methadone is diverted for illicit uses.