Intranasal absorption of physostigmine and arecoline.

Physostigmine, an acetyl cholinesterase inhibitor, and arecoline, a muscarinic agonist, have been shown to improve Alzheimer presenile dementia in some patients when administered parenterally. Both of these compounds are ineffective orally due to first-pass metabolism. The nasal route was examined as an alternative route of administration for both drugs. Nasal bioavailabilities and dispositions for both drugs were determined in rats. Physostigmine nasal bioavailability was 100% as compared with iv bioavailability, and that of arecoline was 85% when compared with bioavailability following im administration.