High-performance liquid chromatographic method for the determination of atracurium and laudanosine in human plasma. Application to pharmacokinetics.

A high-performance liquid chromatographic method coupled with fluorimetric detection has been developed for the determination of atracurium and its major metabolite, laudanosine, in human plasma. The detection is performed at 240 nm for excitation and 320 nm for emission. Verapamil was used as the internal standard. The proposed technique, involving the direct precipitation of plasma proteins is reproducible, selective and sensitive. Linear detector responses were observed for the calibration curve standards in the range of 40 to 2000 ng/ml. Precision, expressed as C.V., was in the range 1 to 14%. The limit of quantification for both atracurium and laudanosine was 40 ng/ml. The method has been validated and stability tests under various conditions have been performed. This method has been used to determine the pharmacokinetic profile of atracurium and laudanosine in patients with acute respiratory distress syndrome.