Methylphenidate [dl-threo-methyl-2-phenyl-2- (2-piperidyl) acetate]
is a CNS stimulant. Although methylphenidate has two chiral
centres, the drug used in therapy comprises only the threo pair of
enantiomers, which are more potent pharmacologically than the
corresponding erythro racemate. Moreover, d-threo-methylphenidate
has been shown to be much more potent than the l-enantiomer
(
Kimko et al,
1999).