An analytical method for cyclosporine using liquid chromatography-mass spectrometry

Area of Science:

• Pharmacology
• Analytical Chemistry
• Biochemistry

Background:

• Cyclosporine A (CyA) is an immunosuppressant drug with a narrow therapeutic index.
• Accurate quantification of CyA in biological matrices is crucial for pharmacokinetic studies and therapeutic drug monitoring.
• Existing methods may lack the sensitivity or throughput required for extensive preclinical research.

Purpose of the Study:

• To develop and validate a sensitive and reliable liquid chromatographic-mass spectrometric (LC-MS) assay for quantifying cyclosporine A (CyA) in rat plasma.
• To establish the assay's suitability for application in rat pharmacokinetic studies.

Main Methods:

• A liquid-liquid extraction method was employed using ether:methanol for sample preparation.
• Analysis was performed using a C(8) column with a specific mobile phase composition under isocratic conditions.
• Quantification was achieved via LC-MS, monitoring specific ions for CyA and amiodarone (internal standard).

Main Results:

• The assay demonstrated excellent linearity (r² > 0.99) over a wide concentration range (50-5000 ng/mL).
• The method exhibited high precision and accuracy, with coefficients of variation (CV%) and mean errors below 19%.
• The lower limit of quantification was determined to be 50 ng/mL, indicating significant sensitivity.

Conclusions:

• The developed LC-MS assay is highly linear, sensitive, reliable, and precise.
• This validated method is well-suited for determining cyclosporine A concentrations in rat plasma for pharmacokinetic investigations.