introduction of QSAR

2. SAR
•SAR is relationship between the
chemical structure of a molecule and its
biological activity refined to build
mathematical relationship between
chemical structure and the biological
activity.

3. QSAR
A quantitative structure activity relationship (QSAR) is a
mathematical relationship which corelates measurable or
calculable molecular properties to some specific
biological activity in terms of an equation.
It is computerized statistical method of drug designing.

4. • QSAR
• Physiochemical parameters:
Solubility
Partition coefficient
Protein binding
Log P (biological activity)
QSAR also applies mathematically derived
formulas.
Numerical parameters

5. Objectives of QSAR
Prediction of biological activity with their
parameters or their nature or position of
substitution.
QSAR gives positive influence on compound to
be guessed.
Understanding the mechanism of action of drug.
Lead compound search by CADD.
Economise the new drug development.
Reduction of usage of animals

6. PARTITION COEFFICIENT
• It is ratio of concentrations of the unionized drug or compound
between two liquid phase.
• The log of ratio of concentration of the unionized solute in the
solvent is called log P.
• One of the solvent is water and other one is non polar solvent.
• Log p value is also known as a measure of lipophilicity.

7. TAFT STERIC PARAMETER
• The interaction of drug with its receptor is influenced by
steric factor of drug.
• The bulk nature of drug size and shape influence its binding
capacity with enzyme or receptor.
• Steric parameter uses a computer programme to calculate the
steric substituent values like vanderwaals radius, bond
length, bond angles etc.
• This effect is reflected for duration of action.

8. DATA ANALYSIS
• The data of biological activity and the values of
parameters generated by software should be analysed to
get a meaningful QSAR model (lead model)
• QSAR model is considered as a LEAD model to enter into
preclinical and clinical trials.
• It helps to know the better pharmacological activity.