Define Drugs. Discuss different sources of drug with example.

Drug: Any substance or product that is used or intended to be used to modify or explore physiological system or pathological states for the benefit of the recipient is called drug. The benefit of the recipient includes:
1. The diagnosis of disease. e.g. Barium salt, Lopamodol
2. The prevention of disease. e.g. Vaccines
3. The control of disease. e.g. Insulin to control diabetes, Anti-hypertensive to control hypertension.
4. The treatment of disease. e.g. Antibiotics to treat infection.

Sources of drugs:

1. Natural
1. Animal source. e.g. Insulin, Heparin, Gonadotropin
2. Plant source. 
• Alkaloids. e.g. Atropine, Morphine, Ergotamine
• Glycosides. e.g. Digoxin, Digitoxin.
• Oil. e.g. Olive oil, Castor oil
• Tannin. e.g. Tincture of catechu
3. Minerals. e.g. Ferous Fumerate, Liquid paraffin
4. Micro-organism. e.g. Penicillin, Chloramphenicol, Tetracycline
2. Synthetic. e.g. Aspirin, Sulfonamides, Paracetamol
3. Semi synthetic. e.g. Pethidine, Ampicillin
4. Recombinant DNA technology. e.g. Human Insulin