antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of such infections.

1. ANTIBIOTICS
ABHISHEK SHANKAR BORKAR
Student of B-pharm( 3rd yr)
Shraddha institute of pharmacy washim

2. CONTENTS
• INTRODUCTION
• HISTORY OF ANTIBIOTICS
• CLASSIFICATION
• MECHANISMS OF ACTION
• STRUCTURE –ACTIVITY RELATIONSHIPS
• References

3. INTRODUCTION
• Antibiotics are the agent that produced by one microorganism and kill or
inhibits the growth of other microorganism .
• Medication used to treat bacterial infections.
• The term antibiotic first used in 1942 by SELMAN WAKSMAN

4. HISTORY OF ANTIBIOTICS
• First Antibiotics discovered by Alexander Fleming is PENICILLIN
• Penicillin in discovered in 1929
• it was first antibiotics
• His working in his lab ,trying to kill a deadly bacteria ,when he noticed a blue mold growing
on dish .

5. What is an antibiotic
Antibiotic is from antibiosis ,
means against life
A substances derived from a microorganism or produced synthetically
(Quinolones,Sulfonamides )
To that kill or inhibits the growth of microorganisms.

6. GENERAL STRUCTURE OF PENICILLIN
Properties of PenicillinG:-
• Active againstGram +ve bacilli (Staphylococci,
meningitis and gonorrhea) and many (but not all)
Gram –veCocci.
• Non-toxic –The penicillin are amongst the safest drugs
known to medicine.
• Not active over a wide range (or spectrum) of bacteria.
• Ineffective when taken orally since it breaks
down in the acid condition of the stomach
• PenicillinG can only be administered by injection

7. On the basis of spectrum of antimicrobial
activity
1. Narrow Spectrum antibiotics
e.g. Benzyl penicillin , Bacitracin
2. Broad Spectrum antibiotics
e.g. Chloramphenicol , Streptomycin
Antibiotics Classifcation

8. # On the basis of chemical strucher
A ) Beta lactam antibiotics
Eg.Benzyl penicillin, Ampicillin, Amoxicillin
B)Non –beta lactam antibiotics
E.g. .tetracycline ,Streptomycin
C) Miscellaneous antibiotics
E.g. .chloramphenicol

9. A. BETA LACTAM ANTIBIOTIC
1) BENZYL PENICILLIN
Uses :- Meningitis , Aspiration pneumonia , Diphtheria

10. 2. AMPICILLIN
Uses:- Bacterial Meningitis , Endocarditis, Bronchitis .

11. 2. NON –BETA LACTAM ANTIBIOTICS
1.TETRACYCLIN
Uses:- Plague , Rickettsia infections

12. 2.STREPTOMYCIN
Uses :-Tuberculosis ,Endocarditis

13. C) MISCLLANEOUS ANTIBIOTICS
1 .CHLORAMPHENICOL
Uses :-Typhoid, Meningitis, Ferve, UTI.

14. Mechanism of Antibiotics
1. Bacteriostatic
eg. Tetracycline , Chloramphenicol , Trimethoprim
2. Bactericidal
eg. Penicillin, Cephalosporins, Monobabactams

15. STRUCTURE –ACTIVITY RELATIONSHIPS OF
PENICILLINS
• Fused β-lactam and thiazolidine ring forming a bicyclic system
(Penam). Bicyclic system confers strain on the β-lactam ring
• The free carboxylic acid group is essential.
• The strained β-lactam ring is essential (increase strain, increase in activity, increase instability)
• The acyl amino side chain is essential except for thienamycin

16. • Sulfur is usual but not essential
• The stereochemistry of the bicyclic ring with respect to the acyl
amino side chain is important - Cis stereochemistry for the hyd
• Very little variation is tolerated by penicillin nucleus.Also, any
variation which can be made is restricted to the acyl amino side chain

17. REFERENCES
1. Adzitey F. (2015). Antibiotic classes and antibiotic susceptibility of bacterial isolates from
selected poultry; a mini review. World Vet. J. 5 (3):36-41
2. Text book of medicinal chemistry-III by dr sanajay walode