Out of two anticholinesterases, drug 'X' is a teiary amine while drug 'Y' is a quaernary ammonium compound. Then
Drug X is physostigmine and Drug Y is neostigmine. Physostigmine:- It is rapidly absorbed from g.i.t. and parenteral sites. Applied to the eye, it penetrates cornea freely. It crosses blood-brain barrier and is disposed after hydrolysis by ChE. Neostigmine and congeners:- These are poorly absorbed orally; oral dose is 20-30 times higher than parenteral dose. They do not effectively penetrate cornea or cross blood-brain barrier. They are paially hydrolysed and paially excreted unchanged in urine. Ref:- kd tripathi; pg num:-107,108
Drug 'X' is likely to be more potent than 'Y'
Drug 'Y' will produce CNS effects
Drug 'Y' will be completely metabolized in the body
Drug 'X' will be more suitable to be used as a miotic
Autonomic nervous system