Detection of codeine and phenobarbital in sweat collected with a sweat patch

Area of Science:

• Pharmacokinetics
• Analytical Chemistry
• Forensic Toxicology

Background:

• Drug monitoring is crucial for compliance and forensic purposes.
• Traditional methods for drug testing have limitations in continuous surveillance.
• Sweat patches offer a potential non-invasive method for long-term drug detection.

Purpose of the Study:

• To evaluate the utility of sweat patches for monitoring codeine and phenobarbital.
• To determine the pharmacokinetic profile of these drugs in sweat.
• To assess factors influencing drug concentration in sweat patches.

Main Methods:

• Administration of single doses of codeine (90 mg) and phenobarbital (100 mg) to human subjects.
• Collection of sweat using Sudormed sweat patches over a 1-week period.
• Quantification of drug concentrations using gas chromatography-mass spectrometry (GC-MS).

Main Results:

• Codeine was detected within 1 hour, with peak concentrations between 12-24 hours and plateau on day 3.
• Phenobarbital was detected after 3 hours, with continuous excretion over the week.
• Significant intersubject variability (1-5 fold) and site-dependent variations (1-3 fold) in drug concentrations were observed.

Conclusions:

• Sweat patch technology provides a viable method for documenting drug use over a 1-week period.
• Pharmacokinetic data and variability factors are important considerations for interpreting sweat patch results.
• This method holds promise for drug surveillance applications.