The document discusses the field of medicinal chemistry, which involves the discovery and development of therapeutic chemicals into medicines. Medicinal chemistry is an interdisciplinary field at the interface of organic chemistry and life sciences. It includes the synthesis of new drug candidates, determining their structure-activity relationships, and studying how they are absorbed, distributed, and metabolized in the body. The goal is to design and discover new compounds that can be used safely as drugs through a process involving chemistry, biology, and other disciplines.

1. ST JOHN’S UNIVERSITY OF TANZANIA
FACULTY OF NATURAL AND APPLIED SCIENCES
CHEMISTRY DEPT
CHE 326: MEDICINAL CHEMISTRY
Instructors: SHADRACK, M. AND DOMINIC P.
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2. Medicinal Chemistry
• Medicinal chemistry is the science
that deals with the discovery of
therapeutic chemicals and their
development into useful medicines
• Medicinal chemistry has been
practiced for thousands of years
• The earliest written records of the
African, Chinese, Indian, South
American, and Mediterranean
cultures and biblical languages
describe the therapeutic effects of
various plant concoctions
• Man has search for cures by chewing
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bark, roots, leaves and berries 2

3. Medicinal chemistry
is defined as the branch of science that
studies pharmaceuticals and their
mode of action in the organism.
Pharmaceuticals are substances,
other than food that are
administered to alleviate the effect
or treat the cause of disease.
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4. Medicinal chemistry
• The science that deals with the discovery
or design of new therapeutic agents and
their development into useful medicines.
• It involves:
• Synthesis
• Structure-Activity Relationships (SAR)
• Receptor interactions
• Absorption, distribution, metabolism, and
excretion (ADME)
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5. Introduction, cont…,
• The primary objective of medicinal
chemistry is the design and discovery of
new compounds that are suitable for use
as drugs.
• This process involves a team of workers
from a wide range of disciplines such as
chemistry, biology biochemistry,
pharmacology, mathematics, medicine
and computing, amongst others.
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6. • Hence medicinal chemistry is an
interdisplinary disciplines
It also involves
• Chemistry- based disciplines
• Organic chemistry life science
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7. • Summary
Medicinal Chemistry is an interdisciplinary
science situated at the interface of organic
chemistry and life sciences (such as biochemistry,
pharmacology, molecular biology, immunology,
pharmacokinetics and toxicology) on one side and
chemistry-based disciplines (such as physical
chemistry, crystallography, spectroscopy and
computer-based information technologies) on the
other.
Medicinal Chemistry
Organic Chemistry
Chemistry based Life Sciences
disciplines
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8. • The discovery or design of a new drug not only
requires a discovery or design process but also:
– The synthesis of drug
– A method of administration
– The development of tests and procedure to
establish how it operates in the body, and
– Safety assessment
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9. • Drug discovery may also require fundamental
research into the biological and chemical
nature of the diseased state.
• These and other aspects of drug design and
discovery require input from specialists in
many other fields and so medicinal chemists
need to have an outline knowledge of the
relevant aspects of these fields.
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10. Where Did (Do) Our Drugs Come From?
Natural sources.
• Since ancient times the peoples of
the world have had a wide range of
natural products that they use for
medicinal purposes.
• These products, obtained from
animal, plants & vegetable and
mineral sources, were sometimes
very effective.
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11. New drugs from old poisons
CH3 O
HO CH3O
O
CH3 O O
HO O N CH3 CH3O O
N CH3 O H N CH3
H O H
O
HO HO
O O CH3 N CH3 O
morphine
N CH 3 H codeine N CH3
H O heroin H
HO HO
O CH3
morphine codeine
heroin
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12. Note.
At least a quarter of all prescription dispensed in
the US and UK contains, as active cpds,
molecules derived from flowering plants.
Other data show that 12 out of the 25 highest
earning drugs in 1995 were natural products
The importance of plants as medicines in the
developing world should be also be
acknowledged, here they are estimated to
comprise 80% of the medication uses in the
primary health care. (source, Houghton, P.J
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13. “Roots of remedies: Plants, plants and
pharmaceuticals”, Chem Ind. 1995)
Other Examples of Natural Products as
Leads & Drugs
Cardiac glycosides, morphine, quinine,
salicylic acid, taxol, camptothecin, penicillin,
cyclosporin A, warfarin, artemisine
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16. Organic synthetic agents
• Drugs have been synthesized from other drugs
using synthesizing agents.
For example.
• Paul Ehrlich was looking for a safer
antiprotozoal agent with which to treat
syphilis than the then currently used atoxyl.
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18. The synthesis of penicillin analogue.
e.g Ampicillin
Penicillin G both synthesized from penicillin
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21. General process of drug discovery
• Medicinal chemistry relates to
the design and production of
compounds that can be used in
medicine for the prevention,
treatment or cure of human and
animal diseases
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22. General process of drug discovery
Three critical steps
Discovery
Optimization
Development
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23. Drug discovery cont…,
• A discovery step consisting of the identification and
production of new active substances usually called lead
compounds. Leads can originate from synthetic organic
chemistry, from natural sources or from biotechnological
processes.
• An optimization step that deals mainly with the synthetic
modification of the lead structure in order to improve
potency, selectivity and lessen toxicity. Its characteristics
are the establishment and analysis of structure-activity
relationships (SAR).
• A development step consisting of:
– the optimization of the synthetic route for bulk
production
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24. - modification of the pharmacokinetic and
pharmaceutical properties of the active
substance to render it suitable for clinical
use. This may cover optimization of
properties associated with:
• Chemical formulation
• Solubility
• Elimination of unpleasant taste or
irritation
• Reduction of pain at site of injection
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