Opioid disposition in human sweat after controlled oral codeine administration

Area of Science:

• Pharmacology
• Analytical Chemistry
• Forensic Science

Background:

• Accurate interpretation of sweat tests is crucial for drug treatment, criminal justice, and workplace drug testing.
• Understanding opioid excretion in sweat supports these critical applications.

Purpose of the Study:

• To characterize codeine excretion in sweat following controlled dosing.
• To evaluate the utility of sweat patches for opioid monitoring.

Main Methods:

• Twenty participants received codeine sulfate doses (low or high) or placebo.
• PharmChek Sweat Patches collected sweat samples hourly and weekly.
• Gas chromatography-mass spectrometry analyzed patches for codeine and metabolites.

Main Results:

• Codeine was the sole detected analyte in sweat patches.
• Detectable codeine concentrations persisted up to two weeks post-dosing.
• A significant percentage of weekly patches met the proposed Substance Abuse and Mental Health Services Administration cutoff.

Conclusions:

• Codeine is detectable in sweat for an extended period after administration.
• Sweat testing demonstrates potential as an alternative for qualitative opioid use monitoring.
• Observed variability in codeine concentrations is attributed to complex deposition processes.