Determination Drug Concentration Of Levetiracetam By HPLC In Epilepsia Childrens' Serum

Objective: Epilepsy is a chronic disease of the nervous system,which has high morbidity and mortality. AEDs are still the main way of epilepsy treatment. The relationship of the clinical effect - concentration has been established.Levetiracetam(LEV) is a novel antiepileptic drug, which has been confirmed in some studies for big individual differences in metabolism,and narrow therapeutic window.There has a wide variability in concentration-response relationships .The levetiracetam plasma concentration in plasma could be used to help clinicians to adjust dose,to prevent severe intoxication or to verify compliance by repeating the measurement in patients.Therefore, the objective of this study is to establish a high performance liquid chromatography (HPLC)method to determine levetiracetam concentration in epilepsy patients'serum, with characteristics of convenient performance,high performance,high specificity,high sensitivity,high stability and high precision.Methods:Useα-phenacyl bromide(α-BT) was used as internal standard (IS),extracting LEV and IS by liquid extraction with ethyl acetate from plasma. LEV and IS was dried and condensed by Nitrogen fumes (N2)continuous flow,then dissolved by mobile phase(20mL). The mobile phase was a mixture of phosphate buffer and acetonitrile(92:8,v/v)at an isocratic flow rate of 1.0mL/min.HPLC analysis was carried out on a Xterra RP C18 , 5μm, 150mm×3.9mm analytical column,at wave length 210nm. LEV and IS peak area ratios was recorded , then formulated working curve of concentration.Results : Calibration curves showed a linear and reproducible correlation between LEV plasma concentrations and matched analyte-to-I.S. peak area ratios at the concentration range of 0.234～60.00μg/mL. The equation of the regression line was:y=0.06514x-0.0047,r= 0.9995.The minimum quantitation limit was 0.234μg/mL( S/N=4.8) and the absolute recovery was89.18±3.57%. The relative standard deviation(RSD) of inter and intra-day precision was 5.84±2.15% and5.48±2.61% respectivly .The stability of freeze thawing was less than 5%.It could separate drugs combination and the interference from those drugs completely(resolving power [R]≥1.5). RSD of quality contro(luse single blind method) was﹤4%.Conclusion:This method attain the determination requisition of blood serum sample with technically confirmed , with characteristics of convenient performance , high performance , high specificity , high sensitivity , high stability.It could be used in drugs concentration measurement in clinical and pharmacokinetic study.