Radiolabeling of Zonisamide for a Diagnostic Perspective.

Objective: Epilepsy is one of the oldest and the most common chronic neurological diseases. Antiepileptic drugs (AEDs) are the backbone of epilepsy treatment. However, epileptogenesis has not been fully elucidated. One of the critical reasons for this is the lack of reliable biomarkers. Neuroimaging suggests a non-invasive examination and investigation tool that can detect critical pathophysiological changes involved in epileptogenesis and monitor disease progression. In the current study, the radiolabeling potential of Zonisamide (ZNS) (the secondgeneration AED) with Technetium-^99m (^99mTc) is examined to neuroimage the epileptogenic processes by contributing to the development of potential radiotracers.

Methods: ZNS was labeled with ^99mTc and the radiochemical yield of [^99mTc]Tc-ZNS was determined with TLRC (Thin Layer Liquid Radio Chromatography and HPLRC (High Performance Liquid Radio Chromatography) radiochromatographic methods. In vitro behavior of [^99mTc]Tc-ZNS was determined with time-dependent uptake of [^99mTc]Tc-ZNS on the SHSY5Y human neuroblastoma cells.

Results: The radiochemical yield of [^99mTc]Tc-ZNS was determined as 98.03 ± 1.24% (n = 6) according to radiochromatographic studies results. [^99mTc]Tc-ZNS demonstrated 5.38 and 6.18 times higher uptake values than the control group on the human neuroblastoma SH-SY5Y cell line at 120 and 240 minutes, respectively.

Conclusion: This study showed that the current radiolabeled antiepileptic drug has a diagnostic potential to be used in imaging neurological processes.