Drugs or pharmaceuticals are substances or combinations used to diagnose, cure, treat, or prevent disease.

Basic info about drugs

Drugs may be synthetic chemicals, chemicals obtained from plants or animals, or products of genetic engineering.

Drug or medicine?

A medicine is a chemical preparation, which usually, but not necessarily, contains one or more drugs, administered with the intention of producing a therapeutic effect. Medicines usually contain other substances (excipients, stabilisers, solvents, etc.)

Basic outline of drug utilisation in the body

A drug is a chemical molecule. Following introduction into the body, a drug must pass through many barriers, survive alternate sites of attachment and storage, and avoid significant metabolic destruction before it reaches the site of action.

Metabolism plays a central role in the elimination of drugs and other foreign compounds (xenobiotics) from the body. Drug metabolism reactions have been divided into two categories: phase I (functionalization) and phase II (conjugation) reactions

Sample questions are based on (just few examples)

  • Important functional groups in a drug molecule
  • How a certain drug is biotransformed
  • Chemistry related to drugs e.g. assaying, pharmacokinetics etc

Useful links

General Summary of Phase I and Phase II Metabolic Pathways

Mechanism of Drug Action -An Introduction


  • RANG AND DALE’S Pharmacology(Chapter 1) 8th ed.
  • Wilson and Gisvold’s Textbook of Organic Medicinal and Pharmaceutical Chemistry (12th ed)