Determination of Related Substances in Compound Sodium Valproate and Valproic Acid SR Tablets by GC

OBJECTIVE To develop a capillary gas chromatography(GC) method for determination of related substances in Compound Sodium Valproate and Valproic Acid SR tablets. METHODS The CGC column was PEG-20M(HP-FFAP, 30 m×0.53 mm, 1 μm), temperature programming. N₂ as carrier gas (flow rate:10 mL·min^-1). The temperature of the injection port was maintained at 200℃, and that of the flame-ionization detector(FID) was 250℃. The injection volume was 1.0 μL. RESULTS The method was specific. Valproic acid had a good linear relationship in the range of 1.01-8.06 μg·mL^-1(r=0.998 2, n=5) and the lowest limit of detection was 0.403 μg·mL^-1. The relative recovery was >90%, and the RSD was <5%. CONCLUSION The method can be used for the determination of related substances in Compound Sodium Valproate and Valproic Acid SR tablets.