The effects of collection methods on oral fluid codeine concentrations

Area of Science:

• Forensic Toxicology
• Pharmacokinetics
• Analytical Chemistry

Background:

• Oral fluid is an emerging alternative biological specimen for drug detection and quantitation.
• Limited literature exists on collection methods, drug pharmacokinetics, and disposition in oral fluid.
• The impact of various collection techniques on oral fluid drug concentrations requires thorough evaluation.

Purpose of the Study:

• To determine the effects of five oral fluid collection techniques and devices on codeine concentrations.
• To evaluate the impact of collection methods on pharmacokinetic parameters derived from oral fluid.

Main Methods:

• A controlled clinical study using codeine as the analyte.
• Five collection techniques: control (spitting), acidic stimulation, nonacidic stimulation, Salivette device, and Finger Collector device.
• In vitro drug recovery evaluation for Salivette and Finger Collector devices.

Main Results:

• Control (spitting) method consistently yielded higher codeine concentrations (1.3-3.6 times) compared to other methods.
• Collection method significantly affected elimination rate constant and half-life (t(1/2)), with acidic stimulation showing a shorter t(1/2).
• Salivette device demonstrated higher recovery rates and volumes compared to the Finger Collector.

Conclusions:

• Collection technique significantly influences oral fluid drug concentrations and pharmacokinetic parameters.
• The control (spitting) method generally results in higher concentrations, potentially due to oral contamination.
• Device choice impacts sample volume recovery and in vitro drug recovery, with Salivette showing better performance than Finger Collector.