It definitely is a memorial issue for Claudius. Which one, I'm not exactly sure, but I think it may have been part of an issue of Constantine I (the Great), when he was trying to support his claim of family ties to Claudius II Gothicus (who died of plague) and the throne. If it is a small coin (dime sized), I would go this route.
If it is a larger, thick coin, I would have to guess it was a memorial issue of Claudius I, possibly issued by Nero (whose mother poisoned Claudius, IIRC).
Can you tell us the diameter of the coin?
-- Tom