Validation of a sensitive bioanalytical method for metronidazole extraction from human plasma

Area of Science:

• Pharmacology
• Analytical Chemistry
• Bioanalysis

Background:

• Metronidazole (MTZ) is a broad-spectrum antibiotic.
• Topical MTZ application leads to low systemic absorption, necessitating sensitive plasma quantification.
• Existing methods struggle to detect low MTZ concentrations post-topical application.

Purpose of the Study:

• To validate a simple, sensitive liquid-liquid extraction method for quantifying metronidazole (MTZ) in human plasma.
• To improve the detection limit for MTZ plasma concentrations following topical administration.

Main Methods:

• Liquid-liquid extraction of MTZ from plasma using an ethyl acetate and acetonitrile mixture.
• Quantification of MTZ using Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS).
• Validation of the extraction method for recovery, precision, accuracy, and stability.

Main Results:

• High MTZ recovery (93.7-97.5%) and excellent linearity (R²=0.999) were achieved.
• The method demonstrated superior autosampler and freeze-thaw stability.
• A low limit of quantification (0.53 ng/mL) was established, surpassing previous methods.

Conclusions:

• The validated liquid-liquid extraction method is highly efficient for detecting trace MTZ levels in plasma.
• This assay enables accurate quantification of MTZ after topical application.
• The method is suitable for bioanalytical studies requiring sensitive MTZ measurement.