Drug Action and Drug Design. Stereoisomers. Stereoisomers are isomers with the same molecular formula AND the same structural formula, but a different arrangement of atoms in space. Geometric isomers:
The beta-lactam ring is circled in orange.
Structure of Penicillin:
Comparison of structures:
Although diamorphine (heroin) and morphine share the same basic structure, heroin is more potent and thus more addictive because of its polarity due to the presence of its functional groups.
Heroin (left) Morphine (right)