Stereochemistry of Steroid Drugs

Importance of Stereochemistry:

• 3D Orientation: The spatial arrangement of atoms affects receptor binding and biological activity.

• Chirality Centers: Steroids contain multiple chiral centers, leading to various isomers with distinct effects.

Stereochemistry of Steroid Drugs

Key Stereochemical Features:

• Alpha (α) and Beta (β) Configurations: 

  • Define the orientation of functional groups relative to the steroid nucleus.

• Double Bonds and Rings:

  • Δ4, Δ5, Δ9, etc.: Indicate the position of double bonds, influencing drug activity and metabolism.

• Substituent Positions:

  • C17α vs. C17β: Placement of hydroxyl or other groups at carbon 17 affects potency and receptor affinity.

Examples:

• Dexamethasone vs. Betamethasone: Minor stereochemical differences lead to variations in glucocorticoid potency.

• Testosterone vs. Dihydrotestosterone (DHT): DHT has a different stereochemistry, making it a more potent androgen.