DETERMINATION OF THE POLAR DRUG DIMIRACETAM IN HUMAN PLASMA AND SERUM BY COLUMN-SWITCHING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A sensitive and fully automated column-switching HPLC method was developed for the determination of a novel cognition enhancer, dimiracetam, in human plasma and serum. A sample of plasma was ultrafiltered and then directly injected onto a first mu Bondapak C-18 column. The sample was eluted with water. The portion of the eluate (heart-cut) from this column containing the drug was selected and loaded on a second mu Bondapak C-18 column and eluted with water. During the elution of the second column, the first column was automatically rinsed with water-acetonitrile (50:50, v/v) and then equilibrated for a new injection. The total analysis time for each sample was 35 min. This corresponded to a 30% decrease in analysis time compared with the time that would have been needed with a simple run with two mu Bondapak C-18 columns assembled in series. Ultraviolet detection at 200 nm was used to monitor the eluate. The method was fully validated over the quantitation range 27 ng/ml-15 mu g/ml. The applicability of the method was demonstrated by analysis of serum samples from a study performed in human healthy volunteers.