Automatic solid-phase extraction and high-performance liquid chromatographic determination of quinidine in plasma

Area of Science:

• Analytical Chemistry
• Clinical Chemistry
• Pharmacology

Background:

• Therapeutic drug monitoring (TDM) is crucial for optimizing patient outcomes with drugs like quinidine.
• Accurate and efficient analytical methods are required for reliable TDM.
• Solid-phase extraction (SPE) is a common sample preparation technique for drug analysis.

Purpose of the Study:

• To evaluate the efficacy of automated on-line solid-phase extraction (SPE) for quinidine analysis.
• To establish a high-performance liquid chromatography (HPLC) method for therapeutic drug monitoring of quinidine.
• To assess the suitability of the Prospekt system for routine clinical applications.

Main Methods:

• High-performance liquid chromatography (HPLC) was employed for quinidine quantification.
• Solid-phase extraction (SPE) was investigated in both off-line and automated on-line modes using the Prospekt system.
• Ultrasep RP-8 reversed-phase column and a specific mobile phase (acetonitrile-water with triethylamine) were utilized for separation.

Main Results:

• Extraction recoveries for quinidine ranged from 97.1% to 99.4% at concentrations of 1-2 µg/ml.
• The automated on-line SPE method demonstrated high efficiency and reproducibility.
• Measured quinidine concentrations in plasma samples fell within the therapeutic range (1.2-3.6 µg/ml).

Conclusions:

• Automated on-line SPE coupled with HPLC is a highly effective method for quinidine TDM.
• The Prospekt system is recommended for routine monitoring of quinidine in clinical plasma samples.
• The developed method ensures accurate quantification of quinidine within its therapeutic window.