What is the Difference Between Isosteres and Bioisosteres?

Isosteres and bioisosteres are related concepts in chemistry, but they have distinct differences:

Isosteres:

• Molecules or ions with similar shape and often electronic properties.
• Have the same number of valence electrons.
• Can be classified into classical and non-classical isosteres, depending on whether they follow easily definable rules or not.

Bioisosteres:

• Biologically active compounds containing an isostere.
• Chemical substituents or groups with similar physical or chemical properties.
• Used in drug design to enhance desired biological activity, reduce toxicity, change bioavailability, or modify the activity of the lead compound.

The key difference between isosteres and bioisosteres is that isosteres are molecules or ions with similar properties, whereas bioisosteres are biologically active compounds consisting of an isostere. In the context of drug development, bioisosteres are used to alter the desired biological activity while maintaining the overall topology of the molecule.

Comparative Table: Isosteres vs Bioisosteres

Here is a table summarizing the differences between isosteres and bioisosteres:

In summary, isosteres are molecules or ions with similar shapes and electronic properties, while bioisosteres are chemical substituents or groups with similar physical or chemical properties that produce broadly similar biological activity. Bioisosteres are important in medicinal chemistry and drug design, where they are used to enhance desired biological or physical properties, reduce toxicity, change bioavailability, or modify the activity of the lead compound.