Automation and validation of the high-performance liquid chromatographic-radioimmunoassay method for the determination of lacidipine in plasma.

The automation and validation of the HPLC-radioimmunoassay (RIA) method for the determination of lacidipine are reported. The solid-phase extraction step was automated by the introduction of the ASPEC system. A two-column system was adopted for the HPLC purification. The RIA was converted from heterogeneous to homogeneous by the scintillation proximity assay system and automated using an automatic dilution system. All characteristics in terms of accuracy, precision, specificity, and linearity resulted similar to the manual version. The quantification limit was set to 40 pg/ml. The new version of the method increased the number of samples assayed per month two- to three-fold.