Drug design is the inventive process of finding new medications based on the knowledge of the biological target. In the most basic sense, drug design involves design of small molecules that are complementary in shape and charge to the bio-molecular target to which they interact and therefore will bind to it. Drug design frequently but not necessarily relies on computer modeling techniques. This type of modeling is often referred to as computer-aided drug design. Types;- Random screening Trial and error method Ethnopharmacology approach Serendipity method Classical pharmacology Chemical structure based drug discovery

1. TRADITIONALDRUG
DESIGN
BY- SANCHIT DHANKHAR
M.PHARMACY

2. INTRODUCTION
Drug design is the inventive process of finding new medications based
on the knowledge of the biological target.
In the most basic sense, drug design involves design of small
molecules that are complementary in shape and charge to the bio-
molecular target to which they interact and therefore will bind to it.
Drug design frequently but not necessarily relies on computer
modeling techniques. This type of modeling is often referred to as
computer-aided drug design.

3. Modeling techniques for prediction of binding affinity are
reasonably successful.
However there are many other properties such as bioavailability,
metabolic half-life, lack of side effects, etc. that first must be optimized
before a ligand can become a safe and efficacious drug.
 These other characteristics are often difficult to optimize using rational
drug
design techniques.

4. Traditionaldrug
design
Traditional drug discovery involves the origin of drug
discovery that evolved in natural
sources, accidental events.
It was not target based and not much systemised as today.
Improved and advancements in pharmaceutical science
and technology made it
evolutionised to much more systemize modern drug
discovery
Traditional methods of drug discovery (known as forward
pharmacology), which rely on trial-and-error testing of
chemical substances on cultured cells or animals, and
matching the apparent effects to treatments.

5. Methodsfor
traditionaldrug
design
Random screening
Trial and error method
Ethnopharmacology approach
Serendipity method
Classical pharmacology
Chemical structure based drug discovery

6. Random
screening
It includes random screening of synthetic compounds or
chemicals or on natural products by bioassay procedures.
Involves two approaches:
1.Screening for selected class of compounds like alkaloids,
flavonoids, etc
2. Screening of randomly selected plants for selected
bioassays

8. Contributionof
random
screening
• Later, the National Cancer Institute (NCI) of National
Institute of Health, USA, studied about 35,000 plant
species for anticancer activity, spending over two
decades from 1960 to 1980.
• It resulted in proving two success stories, which were
those of paclitaxel and camptothecin.

9. Trialanderror
method
Trial and error method includes berries, roots, leaves and
barks could be used for medicinal purposes to alleviate
symptoms of illness.
Examples :Willow bark –contains salicin –fever reducing
in general
• Cinchona bark – contains quinine – fever associated with
malaria
• Chinese herbal remedies – used to treat many illness.

10. Ethnopharmacologyapproach
•Depends on empirical experiences related to the use of botanical drugs for the discovery of
biologically active
New Chemical Entity.
•This process involves the observation, description, and experimental investigation of indigenous
drugs.
•It is based on botany, chemistry, biochemistry, pharmacology, and many other disciplines like
anthropology, archaeology, history, and linguistics
•In history several examples are present.
•Andrographis paniculata was used for dysentery in ethnomedicine and the compounds responsible
for the activity were isolated as andrographolide.
•Morphine from Papaver somniferum,
•Berberine from Berberis aristata,
•Picroside from Picrorrhiza kurroa.

11. Contributionsof
Ethnopharmacol
ogy
•Discovery of artemisinin from Artemesia alba for malaria,
•guggul sterones from Commiphora mukul (for
hyperlipidemia), boswellic acids from Boswellia serrata (anti-
inflammatory)
•bacosides from Bacopa monnieri (nootropic and memory
enhancement) was based on the leads from these codified
systems of medicine prevailing in China and India.

12. Serendipitymethod
•“Serendipity” refers to “an accidental discovery;” i.e, “finding one thing while looking
for
something else
•No scientific discovery has ever been made by pure luck.
•All happy accidents in science have one point in common: “each was
recognized, evaluated and acted upon in the light of the discoverer's total
intellectual experience.”
•The serendipitous discovery of penicillin in 1928 by Alexander Fleming occurs.
•Fleming was engaged in research on influenza when one of his
staphylococcus culture plates had become contaminated and developed a,
mold that created a, bacteria-free circle
•Fleming recognized the possible significance of the bacteria-free circle and by

13. • He found that it, produced a substance that has a
powerful destructive effect on many of the common
bacteria that infect man.
• He named the antibacterial substance liberated
into the fluid in which the mold was grown
“penicillin” after Penicillium notatum, the
contaminant of the staphylococcus colony that led
to the discovery.

14. Classical
pharmacology
•Also known as function based approach.
•Anciently, drug discovery programmes were often
based-successfully-on measuring a complex
response in vivo.
•Such as prevention of experimentally induced seizures,
lowering of blood sugar,
or suppression of an inflammatory response.
•Without the prior identification of a drug target.

15. Examples of FUNCTION based drug discovery
 Usually the Natural sorce derived drug comes in
this approach.
 Some of them enlisted in chart.

17. Chemical structure based drugdiscovery
In 1891: Paul Ehrlich – coined the term chemotherapy, used synthetic chemicals to try
and cure disease.

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