抄録
The assay of free form of valproic acid (VPA) in serum was made on 71 serum specimens of epileptic patients. For the isolation of free VPA, ultrafiltration using micropartition system MPS-1 (Amicon Corp.) was applied and it was confirmed that this system was good in utility. For the lower levels of VPA as in ultrafiltrates, a modified single dilution technique was developed in EMIT assay instead of the standard double dilution procedure. The results were compared with those determined by the gas-liquid chromatography. Results determined by the above two methods were correlated well (r=0.982) and the regression line was y=1.023x-0.143. Ultrafiltration using MPS-1 is very simple and practical, because it requires small amount of serum sample. In 20 serum specimens from patients treated with VPA alone, the mean percentage of free VPA was 12.5±3.9%. The percentage of free VPA and total VPA levels showed a positive correlation (r=0.808).
