Antibiotics are chemical substances produced by microorganisms that kill or inhibit the growth of other microorganisms at low concentrations. Their discovery and use has both ancient roots as well as a modern history beginning in the late 19th century. Key events included Fleming's discovery of penicillin in 1928, the first widespread use of penicillin in the 1940s, and the discovery of other important antibiotics like streptomycin in the 1940s. Antibiotics can be classified based on their structure, function, or spectrum of activity against bacteria.

1. Brief Historical Background
& Classification of
Antibiotics
Tauhidur Rahaman Mondal
Holy Mary Institute of Technology & Science (HITS), College of
Pharmacy

2. Definition
 "Antibiotics are defined as chemical substances or compounds produced by
various species of microorganisms such as bacteria and fungi, which in low
concentrations destroy, kill or inhibit the growth of other species of
microorganisms."
 Greek words ‘anti’ = against ; ‘bios’ = life.
 Vuillemin to define antibiotics literally meaning "against life"

3. Brief Historical Background
 History of antibiotics can be described in WO segments early history and
modern history
 Most important is the discovery of penicillin in by SIR Alexander Fleming.
EARLY HISTORY
 During ancient times:
 Long ago before 20 century there was no proper treatment for diseases.
 The diseases caused by Mycobacterium tuberculosis, Mycobacterium leprae
were not identified Over 2,500 years ago , Chinese used plants and moldy
cheese used to treat infected wounds.
 As early as 500 to 600 BC, molded curd of soybean was used in Chinese folk
medicine to treat boils and carbuncles.

4.  The ancient Egyptians used honey + lint (soft cotton cloth covering and protecting
wounds)+lard (melted fat of pigs) used as ointment for dressing wounds.
 Egyptians have often been found onions in body cavities of mummies. They used onions,
garlic and radish herb therapeutically. Infect they have anti-infective properties.
 Greeks and Indians used molds and other plants to treat infections.
 In Greece and Serbia, moldy bread was traditionally used to treat wounds and infections.
 Warm soil was used by Russians to cure infected wounds.
 Sumerian doctors gave patients beer soup mixed with turtle shells and snake skins.
 Babylonian doctors healed the eyes using a mixture of frog bile and sour milk. Sri
Lankan army used oil cake (sweetmeat) to serve as antibacterial.

5. Modern History
 Late 1800's - Search for antibiotics began with the growing acceptance of the germ
theory of disease(Louis Pasteur was one of the first recognized physicians who observed
that bacteria could be used to kill other bacteria)
 1871 - The surgeon joseph lister found urine contaminated with mould couldn't kill the
bacteria.
 1890’s - German doctors Rudolf emmerich, Oscar low made pyocyanse from microbes.
It was the first antibiotic used in hospitals but the drug did not work.
 1909 - First modem chemotherapeutic agent SALVARSAN for the treatment of
syphilis. (Paul Ehrlich)
 1928 - Scottish bacteriologist Sir Alexander Fleming discovered enzyme lysozyme and
the antibiotic substance penicillin.
 1932 - Gerhard Domagk discovered Prontosil a prodrug.
 1936 - Sulfanilamide the first synthetic sulfonamide in human medicine.

6.  1940 - Invention of Modern Drug Discovery: Ehrlich & The Magic Bullet
means compound that selectively targets a disease causing organism while
having no negative effect on human tissue.
 1940 - First therapeutic use of penicillin by Floury.
 1944 - Selman Waksman made Streptomycin from soil bacteria.
 1948 - Chlortetracycline.
 1957 - Nystatin (fungal infections)
 1970’s - New 4-quinolones(pipemidic acid,oxolinic acid,cinoxacin)
 1980 - Norfloxacin, the first fluoroquinolone.
 1980 - Enroflocacin
 1998 - Smithkline Beecham patented Amoxicillin/clavulanate potassium
tablets the first sold antibiotic under the trade names of Amoxil and trimox .

7. Classification
 Antibiotics classification Antibiotics are usually classified based on their
structure, Function and/or spectrum of activity
 1. Structure molecular structure
B-Lactams Beta-lactam ring Aminoglycosides vary only by side chains
attached to basic structure
 2. Function how the drug works, its mode of a ction.
5 functional groups These are all compo nents or functions necessary for
bacterial growth Targets for antibiotics:
 Inhibitors of cell wall synthesis
 Inhibitors of protein synthesis
 Inhibitors of membrane function

8.  Anti-metabolites
 Inhibitors of nucleic acid synthesis
 3. Spectrum of Activity:
 Narrow spectrum
 Broad Spectrum
 In these discussions, we will primarily structumal similarities also evist use the
functional classification, but will point out where structural similarities also
exist.

9. References
 TEXTBOOK OF MEDICINAL CHEMISTRY (Synthetic & Biochemical
Approach) Vol- II, by Prof. Surendra Nath Pandeya Dr. Sanjay K Pandey
 Principles of Medicinal Chemistry by William O.Foye.
 Google Search Engine.