A great majority (30–50 per cent) of them contain stereocentres, show stereoisomerism and exist as enantiomers.The current trend in drug markets is a rapid increase of the sales of chiral drugs at the expense of the achiral ones. Most of the molecules that make up living organisms are chiral, i.e. show stereoisomerism. For example, all but one of the 20 essential amino acids are chiral.

1. Pharmaceutical Importance of Stereochemistry.
Md. Mahabubur Rahaman.
Student ID- PHA 16010
Department of Pharmacy,
Mawlana Bhashani Science &
Technology University,Bangladesh
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2. Contents:
• Classification of Molecular isomers ;
• Some important facts about stereochemistry;
• Importance of Stereochemistry In Pharmaceuticals
• Example: Ibuprofen
• TheThalidomideTragedy
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3. CLASSIFICATION OF MOLECULAR ISOMERS:
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4. Some important facts about stereochemistry:
• A great majority (30–50 per cent) of them contain stereocentres, show
stereoisomerism and exist as enantiomers.
• The current trend in drug markets is a rapid increase of the sales of chiral drugs at
the expense of the achiral ones.
• Most of the molecules that make up living organisms are chiral, i.e. show
stereoisomerism. For example, all but one of the 20 essential amino acids are
chiral.
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5. Importance of stereochemistry:
So , it is therefore important:
# to understand stereochemistry for a better understanding of drug molecules, their
action and toxicity.
# to be able to use proper nomenclature in describing the drugs themselves
# how drug chirality affects its interaction with drug targets
# and the nature of forces responsible for those interactions.
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6. Importance of stereochemistry:
# Most often only one form shows correct physiological and pharmacological action.
For example, only one enantiomer of morphine is active as an analgesic, only
one enantiomer of glucose is metabolized in our body to give energy and
only one enantiomeric form of adrenaline is a neurotransmitter.
# One enantiomeric form of a drug may be active, and the other may be
inactive, less active or even toxic
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7. Examples-
• Ibuprofen is a popular analgesic and anti-inflammatory drug.There are two
stereoisomeric forms of ibuprofen.This drug can exist as (S)- and (R)-
stereoisomers (enantiomers). Only the (S)-form is active. The (R)-form is
completely inactive, although it is slowly converted in the body to the active
(S)-form
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8. THETHALIDOMIDETRAGEDY:
• In the early 1950s, Chemie Grunenthal, a German pharmaceutical
company, developed a drug called thalidomide. It was prescribed to
prevent nausea or morning sickness in pregnant women. The drug,
however, caused severe adverse effects on thousands of babies who were
exposed to this drug while their mothers were pregnant.The drug caused 12
000 babies to be born with severe birth defects, including limb
deformities such as missing or stunted limbs. Later, it was found that
thalidomide molecule can exist in two stereoisomeric forms; one form is
active as a sedative, but the other is responsible for its teratogenic activity
(the harmful effect on the foetus).
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10. THANKYOU..
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