HIGH-PRESSURE LIQUID-CHROMATOGRAPHIC DETERMINATION OF CYCLOSPORIN-A IN HUMAN-PLASMA

Abstract

Periodic monitoring of plasma drug concentrations may be a means whereby the toxicity of cyclosporin A (CyA) [an immunosuppressant] can be reduced in patients undergoing bone marrow transplantation. A sensitive and specific method for the determination of CyA in plasma using reverse-phase high-pressure liquid chromatography (HPLC) was developed. Cyclosporin D was used as the internal standard. The lower limits of detection are 100 ng/ml in biological fluids and 20 ng/injection onto the column. Plasma samples from patients who received CyA 8-15 mg/kg per day were analyzed. Although all patients experienced toxic or therapeutic effects, plasma concentrations of CyA were consistently < 100 ng/ml when analyzed by this method. Analytical methods currently available for the detection of CyA are evidently unsuitable for the monitoring of patients who receive this agent.