Comparison of Serum Valproic Acid Determination Through Gas and High Performance Liquid Chromatography Methods

Background: valproic acid is widely used as an anticonvulsant and mood-stabilizing drug in the treatment of epilepsy. determination of serum valproic acid is required in epilepsy therapy for efficient control of seizures. objectives: in the present study, the gas chromatography method was applied to determine serum valproic acid and resulting data were compared with those obtained by high performance liquid chromatography. materials and methods: two methods were used: assayed patients' serum samples and serum quality control materials for laboratory diagnostics applied to high performance liquid chromatography (hplc) and gas chromatography (gc). all chemicals had a grade suitable for analysis. results: the obtained results in both systems were in agreement regarding linearity, correlation and recovery. the results revealed a lower gc limit of quantification (8 μg/ml), a better intra-assay coefficient of variation (cv) (3.86% - 3.99%) and inter-assay cv (6.14% - 6.42%) for all three levels of control materials. in addition, a shorter run time of the gc vs. the hplc chromatographic step (6 minutes vs. 17 minutes) was observed. conclusions: the present study reports a short run time of the chromatographic step as well as a good sensitivity for the gc method. furthermore, the significance of this method is the simplicity in sample preparation step without the need for derivatization and specific detector ensuring cost-effectiveness for the gc analysis. in summary, in comparison with hplc method, our obtained data illustrate a good performance of the gc analytical procedure and confirm its usefulness for the routine quantification of valproic acid level in patients' serum specimens.