Invicro evaluated two methods for radiolabeling adeno-associated virus (AAV) capsid with I-125. An indirect method with [125I]SIB resulted in poor labeling efficiency (<2%). The direct method with [125I]iodide via Pierce iodogen method resulted in excellent efficiency (>90%). The radiolabeled AAV capsid was then purified by SEP cartridge and formulated for intrathecal (IT) administration and stability evaluated by size exclusion HPLC (>90% over 24h at RT).
