Comparative intranasal pharmacokinetics of interferon using two spray systems.

Physician-administered and self-administered interferon (IFN) nasal sprays were compared by measuring residual IFN recovered from the nose at intervals following single doses. Amounts of IFN recovered five minutes after administration and the decay curves of recoverable antiviral and immunoreactive IFN with time were variable between volunteers but similar for both methods. It follows that a self-administered IFN spray would be suitable for future trials of IFN in upper respiratory infections. It was also confirmed that IFN persists in the nose for at least 24 h and is not all recovered by nasal washing, suggesting that it may be bound to, then slowly released from, nasal mucosal cells.