Neostigmine -

Ans. is `a' i.e., It is a quaarnary amounium compound Teiary amine Vs quaenary ammonium compound o Neostigmine is a quaenary ammonium compound. o Quaenary ammonium compounds are lipid insoluble and diffuse poorly across the membrane : - Li Oral absorption ---> Poor CNS penetration --> poor No CNS action Applied to eye No penetration of cornea. More marked effect on skeletal muscles, ganglia, but muscarinic effects are less prominant. o In contrast, physostigmine is a teiary amine derivated. o Teiary amine compounds are lipid soluble and diffuse easily across the membrane :- Oral absorption Good CNS penetration --> Good Produce CNS actions. Applied to eye --> Penetrate cornea. More marked muscarinic and CNS effect.