Simple direct injection high-performance liquid chromatographic method to determine quinidine in plasma

Area of Science:

• Analytical Chemistry
• Chromatography
• Pharmacokinetics

Background:

• Direct plasma injection in HPLC simplifies sample preparation.
• Traditional methods often require complex procedures like column-switching.
• Developing robust methods for direct plasma analysis is crucial for drug monitoring.

Purpose of the Study:

• To develop a rapid and accurate HPLC method for quinidine assay in plasma.
• To evaluate the feasibility of direct plasma injection using a large-pore C18 column.
• To assess the impact of direct injection on column longevity and quantitation limits.

Main Methods:

• Utilized a large-pore (300 Å) Selectosil C18 column for direct injection.
• Analyzed quinidine in plasma and protein solutions.
• Employed high-performance liquid chromatography (HPLC).

Main Results:

• Accurate and rapid assay of quinidine in plasma and protein solutions was achieved.
• Direct injection of 2 microliters of plasma or protein solution onto the column was successful.
• No reduction in column life was observed.
• A limit of quantitation of 0.01 µM was established.

Conclusions:

• Direct injection of plasma onto a large-pore C18 column is a viable method for quinidine analysis.
• This approach offers accuracy, speed, and simplicity in drug monitoring.
• The method is robust and does not compromise analytical column performance.