drug

1. Drug modification
Drug action can be modified in a number of ways ; by
altering its physical properties by adding to it other
substances or other drugs, or by modifying its chemical
structure
The strategy for structural modification is to increase
potency and selectivity, improve physico-chemical,
biochemical and pharmacokinetic properties, eliminate or
reduce side effects.

2. There are many different methods for modifying
drugs, including
1. Structural modification
2. Chemical modification

3. Structural modification
Structural modification of a drug refers to the
process of changing the chemical structure of a
drug to improve its properties.
This can involve changing the functional groups
attached to the drug molecule, altering the
stereochemistry of the molecule, or changing the
size or shape of the molecule. Structural
modification can improve the drug effectiveness,
reduce its side effects, or improve its stability.

4. Proton pump inhibitor
An example of structural modification of a drug is the
development of proton pump inhibitors (PPIs) for the
treatment of acid reflux. PPIs work by inhibiting the
action of the proton pump in the stomach, which reduces
the amount of acid produced.
The first PPI, omeprazole, was developed by modifying
the structure of an earlier drug, a histamine H2 receptor
antagonist.
Modification involved replacing the imidazole ring in the
H2 antagonist with a pyridine ring, which improved the
stability and made it more selective for the proton pump.

6. Statin
modification of a drug is the development of statins for
the treatment of high cholesterol. Statins work by
inhibiting the enzyme HMG-CoA reductase, which is
involved in the production of cholesterol in the liver.
The first statin, lovastatin, was developed by modifying
the structure of a natural product called mevastatin,
which was isolated from a fungus.
The structural modification involved adding a lactone
ring to the mevastatin molecule, which improved its
stability and made it more effective.

7. Chemical modification
Chemical modification of a drug refers to the process
of chemically altering a drug molecule to improve
its properties. This can involve adding functional
groups to the molecule, changing the stereochemistry
of the molecule, or modifying the size or shape of the
molecule. Chemical modification can improve the
Drug effectiveness, reduce its side effects, or improve
its stability.

8. Asprin
An example of chemical modification of a drug is
the development of acetylsalicylic acid,commonly
known as aspirin has been used for centuries as a
pain reliever.
The chemical modification involved adding an
acetyl group to the salicylic acid molecule, which
improved its stability and reduced its side effects.
Aspirin is now widely used as a pain reliever and
anti-inflammatory drug.

9. Methotrexate
Methotrexate, which is used to treat cancer and
autoimmune diseases.
Methotrexate was originally developed as a folic acid
antagonist, which involved modifying the structure of
folic acid to create a molecule that could interfere
with the synthesis of DNA. The chemical
modification involved adding a methyl group to the
folic acid molecule, which made it more effective at
inhibiting the enzyme dihydrofolate reductase.
Methotrexate is now widely used as a chemotherapy
drug and as a treatment for autoimmune diseases
such as rheumatoid arthritis.