Stereoisomers
-possess same molecular formula
-same atom connectivity
-nonsuperposable
-atomic arrangment in space is different
Enantiomers
two mirror-image compounds that are non-superimposable
-identical physical properties
-Non-distinguishable with the exception of their ability to rotate plane-polarized light
Diastereomers
-chiral compounds which are not enantiomers
-not mirror images
Stereochemistry
-the relative 3D spatial arrangement of atoms
-affects all phase of drug action
-receptors are "handed," so stereochemistry of ligands can be important
pharmacodynamic phase
Which phase of drug action do stereoisomers have the most affect on?
conformational, geometric (cis/trans), optical
What are the 3 kinds of stereochemical isomerism?
True
Biological activity of an enantiomer can significantly differ from that of its mirror image. T/F?
Racemic mixture
mixture of equal amounts of two stereoisomers of an optically active substance
diastereomers
Cis-trans isomers are not mirror images therefore they are ___
Optically active
any compound that rotates the plane of polarized light
Levorotatory
left (counterclockwise)
Dextrorotatory
right (clockwise)
Chiral carbons
tetrahedral carbons with 4 different attached groups
achiral
when two attached groups on the carbon are the same
meso compound
a molecule with an internal mirror plane of symmetry
Advantages of Single-Enantiomer Drugs
-increased selectivity
-reduced risk of drug-drug interactions
-less complex pharmacokinetics
-may improve therapeutic response of patients