Education This presentation explores the innovative field of In Silico drug design and virtual screening techniques. In Silico drug design involves using computational methods and simulations to discover and design new therapeutic drugs, while virtual screening allows for rapid evaluation of large compound databases

1. INSILICO DRUG DESIGN AND
VIRTUAL SCREENING
P R E P A R E D B Y M O H D . A N A S
M . P H A R M A 1 S T Y E A R
G U I D E D B Y D R . A R U N K U M A R
I N T E G R A L U N I V E R S I T Y
D E P A R T M E N T O F P H A R M A C E U T I C A L C H E M I S T R Y

2. CONTENTS
• INTRODUCTION
• TYPES
• LIGAND BASED DRUG DESIGN
• STRUCTURE BASED DRUG DESIGN
• VIRTUAL SCREENING TECHNIQUES
• CATEGORIES OF SCREENING
• LIGAND BASED VIRTUAL SCREENING
• STRUCTURAL BASED VIRTUAL SCREENING

3. INTRODUCTION
• Drug Design: Based on the knowledge of the biological target, finding a
new medication is what we called as drug design.
• In Silico drug design: Drug design when performed in computers using
computational software's is known as in silico drug design.
• Since the electronic chips used in the computers are usually made up of
silicon, hence came the name in silico drug design.

4. TYPES
• In silico is also an expression used to mean performed on computer or via computer
simulation.
• Types of In silico Drug Design:
A.Ligand Based Drug Design
B.Structure Based Drug Design

5. LIGAND BASED DRUG DESIGN
• Ligand: It is simply a molecule that binds to another. Often a soluble
molecule such as hormone or neurotransmitter that binds to a receptor.
• In this type of drug design, the receptor is unknown but the ligand is known.
• It is also the statistical analysis of what groups are important for biological
activity.

6. LIGAND BASED DRUG DESIGN
• LBDD relies on the knowledge of other molecules that bind to the biological
target of interest.
• Used to derive a pharmacophore.
• Also defines the minimum necessary structural characteristics a molecule
must possess in order to bind to the target.

7. LIGAND BASED DRUG DESIGN

8. STRUCTURE BASED DRUG DESIGN
• In case of SBDD its just opposite of LBDD, where the receptor is known
whereas the ligand is unknown.
• Completely relies on the knowledge of the 3D structure of the biological target.
• Methods by which the 3D structure of biological target are obtained are
mentioned below.
X-ray crystallography
NMR spectroscopy
Homology modelling

9. BASIC STEPS IN SILICO DRUG
DESIGNING

10. VIRTUAL SCREENING TECHNIQUES
• Virtual screening is a computational technique used in drug discovery to
search the libraries of small molecules in order to identify those structures
which are most likely to bind to a drug target, typically a protein receptor
or enzyme.
• It is also defined as a automatically evaluating very large libraries of
compounds 'using computer programs.

11. CATEGORIES OF SCREENING
• There are two broad categories of screening techniques:
A.Ligand based screening
B.Structure based screening

12. LIGAND BASED VIRTUAL SCREENING
• Ligand-based: A model of the ligand can be built by exploiting the collective
information contained in such set of ligands. These are known as
pharmacophore models.
• A candidate ligand can there be compared to the pharmacophore model to
determine whether it is compatible with it and therefore likely to bind.
• Another approach to LB virtual screening is to use 2D chemical similarity
analysis method to scan a database of molecules against one or more
active ligand structure.

13. LIGAND BASED VIRTUAL SCREENING
• A popular approach to LBVS is based on searching molecules with shape similar to
that of known actives, as such molecules will fit the targets binding site and hence
will be likely to bind the target.
• One of the important type of LBVS is
Similarity based virtual screening: The similar property principle states that
structurally similar molecules tends to have similar properties.

14. LIGAND BASED VIRTUAL SCREENING
• A active reference structure is provided and a database of
compounds are ranked in an order based on similarity to the
reference.
• Select the top ranking compound for biological testing.
• But similarity is inherently subjective, so need to provide a
quantitative basis, a similarity measure, for ranking structures.

15. STRUCTURAL BASED VIRTUAL
SCREENING
• Structural based virtual screening begins with the identification of a potential ligand-
binding site on the target molecule.
• Ideally the target site is a pocket or protuberance having a variety of probable
hydrogen bond donors and acceptors, hydrophobic characteristics, and with
molecular adherence surfaces.
• The ligand-binding site can be the active site as in an enzyme; an assembly site with
another macromolecule or a communication site, which is necessary in the
mechanism of the molecule.

16. STRUCTURAL BASED VIRTUAL
SCREENING
• Determining the structure of a target protein by NMR,X-ray crystallography
or homology modelling befalls as a major and initializing stair in structure
based virtual screening.
• Numerous X-ray crystallographic and NMR studies are helpful in
determining the Virtual Screening perimental structures of ligands bound to
the enzymes, serve as a major source of ideas for analogue design, intern
useful for the docking studies.

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