A simple assay for determination of levetiracetam in rat dried blood spots by LC-MS/MS.

BACKGROUND: A simple LC-MS/MS method was developed and validated for the quantification of levetiracetam (LEV, Keppra®), a broad-spectrum antiepileptic drug (AED) in rat dried blood spots (DBS). LEV was simply extracted with methanol spiked with adenosine (ADE) as IS before LC-MS/MS analysis. The correlation between the DBS and plasma concentrations of LEV was also determined.

RESULTS: Linearity was from 0.067-60 µg/ml for LEV in DBS samples. The intra- and inter-day accuracy and precision of the assay met validation acceptance criteria. The developed assay was applied to monitor levetiracetam DBS levels in Sprague-Dawley rats after intravenous administration. DBS concentrations were well correlated to the plasma concentrations (R² = 0.9399), as fraction of LEV bound to blood cells remains very constant (0.466 ± 0.041) over a wide concentration range.

CONCLUSION: The study illustrated that DBS could be used as alternative matrix for monitoring LEV in preclinical studies.