BACKGROUND: With the outbreak of COVID-19, it has become very important to improve biosafety measures taken by medical staff. Fewer pretreatment steps correspond to lower chances of infection. The authors established a direct injection technique to analyze levetiracetam (LEV) concentrations in human serum and studied its application in therapeutic drug monitoring. METHODS: Serum samples were prepared by hollow fiber centrifugal ultrafiltration and the filtrate was directly injected into a UHPLC apparatus (Waters UPLC BEH C18 column: 50 mm × 2.1 mm, 1.7 µm) for analysis. The mobile phase consisted of acetonitrile and water (8:92) at a flow rate of 1.0 mL/min. The column temperature was maintained at 30°C. The detected wavelength was 210 nm. RESULTS: A linear relationship was obtained for LEV from 0.625 to 80 µg/mL (r = 0.999). The limit of detection (LOD) for the analysis of LEV was 0.125 µg/mL. The analysis time was shortened to 4 min. The recovery rate of LEV based on the current method was 96.6-100.1%, whereas the absolute recovery rate was 93.2-96.8%. The relative standard deviation (RSD) of intraday and interday precision was <7.3%. Stability was achieved at room temperature for 24 hr after 3 freeze-thaw cycles and at -80 °C for 21 days. The method was successfully applied to determine LEV concentrations in the serum of 19 patients. CONCLUSION: The present method is simple, accurate, and sensitive and can improve biosafety with the direct injection technique. It is suitable for the analysis of LEV concentrations in therapeutic drug monitoring.
A Direct Injection Technique to Improve Biosafety to Analyze Levetiracetam Concentrations in Human Serum and Its Application in Therapeutic Drug Monitoring