OBJECTIVE To establish a method for the determination of valproic acid (VPA) in serum ,monitore serum concentration
of VPA in epileptic children,and investigate the relations of VPA serum concentration to dosage and effect of treatment in epil eptic children.METHODS The concentration of VPA were measured by
capillary column gas chromatography a ssay, the column temperature was risen by program.RESULTS The linear relation of VPA were in the range of (20-300) mg ·L -1.Th e delection limit of VPA in serum was 1 mg·L -1.The relative rec overies of 3 concentrations of VPA in serum were 96.2%, 97.1%, 97.6% respectively. The levels of serum VPA in 23 cases epileptic children showed sig nificant difference. The (Css)min concentration was ( 53.8 ± 19.1)mg ·L -1 in 13 children administered orally( 20.8± 3.8)mg ·kg -1·d -1,and was( 65.3± 27.8)mg·L -1 in other 10 children administered oral ly( 32.6± 2.6)mg·kg -1·d -1.CONCLUSION This paper provides selective, rapid,convenient,sensitive and accurate method which is suitable for monitoring serum VPA. It is indicated that the serum conc entrations of VPA in the epileptic children were significant difference. There i s not significant relativity between serum concentration and dosage. VPA might b etter be administered individually to epileptic children.