A fast and sensitive method for quantifying lumefantrine and desbutyl-lumefantrine using LC-MS/MS.

Area of Science:

• Pharmacokinetics and Drug Metabolism
• Analytical Chemistry
• Clinical Diagnostics

Background:

• Accurate quantification of antimalarial drugs like lumefantrine (LUM) and its metabolites is essential for assessing treatment efficacy and understanding drug disposition.
• Existing methods may lack the sensitivity, throughput, or sample volume efficiency required for routine clinical monitoring, particularly in pediatric populations.

Purpose of the Study:

• To develop and validate a sensitive, rapid, and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying LUM and its primary metabolite, desbutyl-lumefantrine (DBL), in human plasma.
• To establish a high-throughput analytical method suitable for pharmacokinetic studies and therapeutic drug monitoring in children.

Main Methods:

• Development of a protein precipitation method using acetonitrile with deuterated internal standards (LUM-d18, DBL-d9).
• Utilized a Hypersil Gold C18 column with a short run time (2.2 min) and a gradient elution involving formic acid in water and methanol.
• Quantification performed using positive electrospray ionization (ESI+) and selected reaction monitoring (SRM) on a tandem mass spectrometer.

Main Results:

• The method demonstrated excellent sensitivity with measuring ranges of 21-529 ng/mL for LUM and 1.9-47 ng/mL for DBL.
• High precision (within 10% CV) and accuracy (within ±10%) were achieved for both analytes across all tested levels.
• The method requires a small plasma volume (100 μL) and exhibits good sample stability, allowing for high-throughput analysis.

Conclusions:

• The validated LC-MS/MS method provides a sensitive, accurate, and efficient means for quantifying LUM and DBL in human plasma.
• This method is suitable for therapeutic drug monitoring and pharmacokinetic studies, particularly in pediatric malaria patients treated with artemether-lumefantrine.
• The assay's high throughput and minimal sample requirement facilitate its application in clinical settings and research.