CORRELATION OF BLOOD LEVETIRACETAM LEVEL WITH CLINICAL SYMPTOMS AFTER VALIDATION BY LIQUID CHROMATOGRAPHY–TANDEM MASS SPECTROMETRY IN EPILEPTIC PATIENTS UNDER THERAPY
Objective: To correlate blood levels of Levetiracetam with clinical symptoms after validating Liquid Chromatography–Tandem Mass Spectrometry method in epileptic patients on therapy.
Material and Methods: This Cross-sectional study was conducted at Toxicology Department, Armed Forces Institute of Pathology, Rawalpindi from July 2018 to December 2019. Blood samples were taken from 120 adult patients of both genders taking Levetiracetam. Samples were extracted with an efficient in-house extracting solvent and were transferred for analysis. Separation was achieved with Agilent Poroshell 120 EC-C18 column (2.1 x75mm, 2.7 micron). A Tandem mass spectrometry was utilized for detection and quantification of drug.
Results: Among 120 patients, 58 (48.3%) were males and 62 (51.7%) were females. The average concentrations of Levetiracetam was 24.54 ±19.50 μg/ml. Mean age was 25.05±6.80 years. History of recurrent fits was present in 28(23.3%). Duration of intake showed 45(37.5%) for less than five months, 65 (54.2%) for five months to one year and only 10 (8.3%) had taken it for more than one year without monitoring. Drug levels was < 10 μg/ml in 28 (23.3%) patients and 10 (8.34%) were having toxic levels ≥ 41 μg/ml in blood. RFTs and LFTs were deranged in 3 (2.5%) patients. Levetiracetam level was significantly (p-value=0.007) different among patients with fit history and (p-value=0.003) among RFTs and LFTs groups while Test of ANOVA of Levetiracetam level showed significant p-value <0.001 in duration of intake groups. Method validation showed accuracy > 90%±10 in three calibrators with linearity from 4.0 to 17 μg/ml. Limit of detection and quantitation were 0.5 μg/ml and 2.0 μg/ml respectively. Precision interassay mean ± SD/CV% μg/ml was 12.9 ± 2.7/1.2 and intra assay was 12.4 ± 8.2/1.4.
Conclusion: Levetiracetam were highly correlated with clinical symptoms, duration of intake. Method validation showed significant precision, accuracy and applicable to patient taking this drug.
Key Words: Levetiracetam, Limit of quantitation (LOQ), Liquid chromatography-mass spectrometry mass spectrometry (LCMS/MS).