High-Performance Liquid-Chromatographic Analysis of Plasma Iohexol Concentrations

Area of Science:

• Analytical Chemistry
• Pharmacokinetics

Background:

• Accurate quantification of plasma iohexol is crucial for assessing kidney function.
• Existing methods may lack the sensitivity or specificity required for reliable pharmacokinetic studies.

Purpose of the Study:

• To develop and validate a high-performance liquid-chromatographic (HPLC) method for quantifying plasma iohexol concentrations.
• To assess the method's accuracy, precision, linearity, and lower limit of quantitation.
• To demonstrate the method's applicability in determining glomerular filtration rates in a porcine model.

Main Methods:

• Plasma protein precipitation using an acetonitrile-ethanol-water mixture.
• Analysis of iohexol using a C-18 reversed-phase column with photodiode array detection under isocratic conditions.
• Validation of the method for linearity, recovery, precision, accuracy, and interference.

Main Results:

• Extraction recovery of iohexol from plasma exceeded 95%.
• Calibration curves demonstrated excellent linearity (R² ≥ 0.9998) over a wide concentration range (10–1500 µg/mL).
• The method exhibited high precision (within-day CVs ≤ 5.1%, between-day CVs ≤ 8.6%) and accuracy (89.0–108.4%).
• The lower limit of quantitation was 10 µg/mL with no significant interferences found in porcine plasma samples.

Conclusions:

• A robust and validated HPLC method for plasma iohexol analysis has been established.
• The method is suitable for pharmacokinetic studies and accurate glomerular filtration rate determination.
• This validated assay provides a reliable tool for preclinical research involving iohexol pharmacokinetics.