Bioisosterism involves the replacement of one part of a molecule by a different part, without significant changes in the physical and chemical properties. The goal is to create new compounds with similar biological activity but improved safety, efficacy, or metabolic stability.
Bioisosteric replacement is a key strategy in medicinal chemistry for optimizing drug candidates. For example, replacing a hydrogen
Optical and Geometrical Isomerism
Isomerism is a phenomenon where two or more compounds have the same molecular formula but different structures or spatial arrangements, leading to different physical and chemical properties.
Optical Isomerism:
This occurs when a molecule can exist in two mirror-image forms known as enantiomers.
These enantiomers can interact differently with plane-polarized light and often have different biological activities.
In drug development, it's crucial to know which enantiomer is biologically active, as the other may be inactive or even harmful.
Geometrical Isomerism:
Also known as cis-trans isomerism, this occurs in molecules with restricted rotation, often around a double bond or a ring structure.
The different isomers can have different shapes and thus different biological activities.
For instance, trans fats (a type of unsaturated fat with trans isomerism) are associated with negative health effects, unlike their cis counterparts.
These types of isomerism are significant in medicinal chemistry because different isomers of a compound can have drastically different pharmacological effects.
Medicinal chemists need to carefully control the stereochemistry of drugs to ensure safety and efficacy.
