Introduction History Requirements Classification Reference

1. 1ST UNIT
ANTIBIOTICS
Prepared by
G.Nikitha, M.Pharmacy
Department of pharmaceutical Chemistry
Subject: Medicinal Chemistry-III
Year- B.Pharmcay 3rd Year
Semister- 2nd semister
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2. CONTENTS
 Introduction
 History
 Requirements
 Classification
 Reference
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3. INTRODUCTION
Definition: Antibiotics are the “chemical substances which
is produced from micro-organisms to kill or inhibit the
growth of micro-organisms With low concentration and
without Effecting the host”.
 The word Antibiotic derived from the Greek word Anti
means Against. Bios means Life.
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4. HISTORY
 Human beings are susceptible to many infectious micro-
organisms like bacteria, fungi, virus etc. From an early
age before 20th century there was no proper treatment for
diseases.
 Diseases caused by bacteria such as Tuberculosis
(Mycobacterium Tuberculosis), Leprosy
(Mycobacterium Laprae) etc although were not identified
but the use of anti-microbial agents for the treatment of
various diseases was practiced even before the discovery
of Antibiotics
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5. HISTORY
 This is evident for the fact that many ancient Egyptian
and Greek had successfully used the knowledge of
moulds for the treating of infections.
 In 1877 Louis Pasteur and Joubart discovered that air
born bacteria can inhibit the growth of antrax bacilin
urine sample.
 In 1899 Emmerich and Low used a crude preparations of
pyocyanose for treating infections like Cholera, Typhoid,
Anthrax etc. Unfortunately the preparation was banned
because of severe toxicity.
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6. HISTORY
 Paul Ehrlich coined the term Chemotherapy defined as
the treatment of systemic or local infections caused by
micro-organisms using chemotherapeutic agents .
 Paul Ehrlich is the father of Modern Chemotherapy and
awarded Noble prize for his contribution in field of
Chemotherapy.
 In 1929 Penicillin was discovered by Alexander Flaming
from Penicillium Notatum for which he was awarded the
Noble Prize.
 In 1941 Florey and Abraham discovered the therapeutic
and biological properties of Penicillin. There was rapid
research on other antibiotics. 6

7. REQUIREMENTS
 Antibiotics should be selectively kill or inhibit the
growth of micro-organisms without producing toxic
effect to the host.
 Antibiotics should be completely eliminate from body.
 Antibiotics should be stable in the form of suitable
dosage form.
 Antibiotics should be highly effective with low
concentration.
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8. CLASSIFICATION
I. Based on spectrum of activity:
a. Narrow Spectrum: It will Kill or inhibit only one type
of Micro-organisms. (Gram Positive or Gram Negative)
Examples: pencillin, Streptomycin, Erythromycin.
b. Broad Spectrum: It will kill or inhibit two types of
Micro-organisms. (Gram Positive and Gram Negative)
Examples: Tetracycline, chloramphenical.
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9. II. Based upon the action:
a. Bacteriostatic: The drugs which inhibit the growth of
micro-organisms.
Examples: Tetracycline, chloramphenical etc
b. Bacteriocidal: The drugs which kills the micro-
organisms.
Examples: pencillin, aminoglycoside, cephalosporin,
Isoniazide, Polypeptide antibiotics etc.
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10. III. Based on source:
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Natural Semi-Synthetic Synthetic
pencillin 6-Amino
pencillonic acid
Isoniazide
Streptomycin 7- Amino
Cephalosporic acid
Chloramphenicol

11. IV. Based on mechanism of action:
a. Inhibition of cell wall: pencillin, cephalosporin.
b. Inhibition of protein synthesis: Tetracycline,
Erythromycin, aminoglycoside.
c. Inhibition of DNA synthesis: sulfonamide,
Flouroquinoline.
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12. V. Based on chemical nature:
a. Beta lactum antibiotics: pencillin, cephalosporin
b. Nitrobenzene derivatives: Chloramphenicol
c. Amioglycosides: Streptomycin
d. Tetracyclines: Chlorotetracycline, oxytetracycline
e. Polypeptide: Polymyoxin,
d. Microlide: Erythromycin
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13. REFERENCE
 Text book of Medicinal chemistry volume-2-3rd edition
by V.Alagarasamy.
 Medicinal chemistry by Rama Rao Nadendla.
 Medicinal Chemistry- 4th edition by Ashutosh Kar
 An Introduction to Medicinal Chemistry- 5th edition
by Graham L. Patrick.
 Medicinal and Pharmaceutical Chemistry by
Harkishan Singh, V.K Kapoor.
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14. THANK YOU
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