On-column propylation method for measuring plasma valproate concentration by gas chromatography

Area of Science:

• Analytical Chemistry
• Clinical Chemistry
• Pharmacokinetics

Background:

• Accurate measurement of plasma valproate is crucial for therapeutic drug monitoring.
• Existing methods may be time-consuming or complex for routine use.

Purpose of the Study:

• To develop and validate a rapid, accurate, and simple gas-chromatographic method for quantifying plasma valproate concentrations.

Main Methods:

• Gas-chromatography with on-column propylation.
• Double-solvent extraction of plasma samples.
• Use of 2-propylhexanoic acid as an internal standard.
• Confirmation of derivative identity using gas chromatography-mass spectrometry.

Main Results:

• The method demonstrated accuracy and simplicity.
• Duplicate plasma sample analysis was achievable within 30 minutes.
• Gas chromatography-mass spectrometry confirmed the identity of propyl ester derivatives.

Conclusions:

• The developed gas-chromatographic method is suitable for routine laboratory use.
• The assay's speed and accuracy facilitate efficient therapeutic drug monitoring of valproate.