Lecture 2 Notes: Functional Groups in Drug Molecules

Introduction

• Discussion on functional groups in drug molecules and their significance.

Functional Groups Examples

• Carboxylic Acid Group: Plays a role in binding to receptors (e.g., ACE inhibitors in hypertension treatment).
• Amines: Varying acidity based on primary, secondary, or tertiary nature.
• Hydroxy Groups: Influence solubility and reactivity.
• Ketones/Aldehydes: Important for structural activity; involved in oxidation reactions.

Role of Functional Groups

• Functional groups determine:
  • Water Solubility: Affects route of administration.
  • Interaction with Biological Targets: Can form hydrogen bonds with receptors.
  • Metabolism/Elimination: Influence drug action duration and side effects.

Drug Binding Mechanisms

Example of ACE Inhibitors

• Function Groups:
  • Carboxylic Acid: Provides ionic bond for interaction with ACE receptor.
  • Hydrophobic Interactions: Essential for effective binding to the receptor.

Example of H2 Receptor Blockers

• Interaction with ionized carboxylic acid group to block H2 receptors.

Potency and Selectivity of Drugs

• Structure-Activity Relationship:
  • Presence of methyl groups can enhance drug activity (e.g., Lovastatin).
  • Morphine vs. its metabolites shows potency differences due to structural modifications.

Absorption and Bioavailability

• Altering functional groups can dramatically change absorption characteristics:
  • Addition of methyl groups can prevent oxidative metabolism, increasing oral bioavailability.
  • Example: Modification of hydroxyl groups can improve absorption rates.

Conclusion

• Understanding functional groups is crucial for optimizing drug design and maximizing therapeutic effects.
• Future lectures will cover the chemical properties of functional groups.

Note: Always focus on how modifications in functional groups can lead to changes in drug properties, efficacy, and safety.