THERAPEUTIC EFFICACY OF STEREOISOMERS

*S.S.Agrawal, Tanya Kumar1 and Mohd Mazhar2
Page No. 1-6

Stereoisomers are molecules that are identical in atomic constitution and bonding, but differ in the
three-dimensional arrangement of the atoms. They are often readily distinguished by biological
systems, however, and may have different pharmacokinetic properties (absorption; distribution,
biotransformation. and excretion) and quantitatively or qualitatively different pharmacologic or
toxicologic effects.Approximately 50% of marketed drugs are chiral having enantiomers and
approximately 50% of these are mixtures of enantiomers rather than single enantiomers. One
member of the pair may show inactivity or toxicty compared to the other one. E.g. granulocytopenia
is related to the d-isomer of levodopa; Vomiting is caused by the d-isomer of levamisole; and
myasthenia gravis symptoms were no longer observed when the d-isomer was removed from
d,lcarnitine) etc.[1]This review article emphasis on the application of optical isomers in medical
research&on issues relating to the study and pharmaceutical activityof individual enantiomers and
racemates.
Key Words: Enantiomer, optical isomer,pharmokinetic properties,arrangement of atoms.