GLC assay for lidocaine in human plasma

Area of Science:

• Analytical Chemistry
• Pharmacology
• Clinical Chemistry

Background:

• Accurate quantification of lidocaine in plasma is essential for therapeutic drug monitoring and pharmacokinetic studies.
• Existing methods may lack the sensitivity, speed, or specificity required for certain clinical applications.

Purpose of the Study:

• To develop and validate a simple, rapid, and highly sensitive method for the gas-liquid chromatography (GLC) analysis of lidocaine in human plasma.
• To assess the method's accuracy, sensitivity, and potential interferences.

Main Methods:

• Plasma samples were deproteinized and centrifuged.
• Mepivacaine hydrochloride was used as the internal standard.
• Lidocaine was extracted into carbon disulfide after alkalinization, followed by GLC analysis with a flame-ionization detector and temperature programming.

Main Results:

• The method demonstrated high sensitivity, accurately measuring plasma lidocaine concentrations between 0.04 and 8.0 µg/ml.
• No significant interference was observed from lidocaine metabolites (monoethylglycinexylidide, glycinexylidide) or common drugs/diagnostic agents.
• The assay is characterized by its simplicity and speed.

Conclusions:

• This GLC method provides a sensitive, rapid, and accurate means for quantifying plasma lidocaine.
• The assay's robustness against common interfering substances makes it suitable for pharmacokinetic investigations.
• The developed method can aid in optimizing lidocaine therapy and understanding its disposition in the body.