Elimination of a quaternary pyridinium salt delivered as its dihydropyridine derivative from brain of mice.

1-Methylpyridine-2-carbaldehyde oxime, a quaternary pyridinium salt, can be delivered efficiently through the blood-brain barrier in its dihydropyridine prodrug form. This redox system was used to study the elimination rate from the brain of a small quaternary salt. It was found that the oxime is eliminated relatively fast from the brain, which supports a hypothesis for the existence of an active transport mechanism for eliminating organic ions from the brain. The possibilities of using the pyridinium salt in equilibrium dihydropyridine redox system for specific delivery of drugs to the brain are discussed.