Cephalosporins are β-lactam antibiotics containing a β-lactam ring fused to a thiazine ring. They were first isolated from the fungus Cephalosporium acremonium. Cephalosporins work by inhibiting bacterial cell wall synthesis through binding to transpeptidase enzymes. They are classified into generations based on their spectrum of activity, with later generations more active against gram-negative bacteria. Common side effects include diarrhea, hypersensitivity reactions, and nephrotoxicity.

1. Mahendra G S
NGSM Institute of Pharmaceutical Sciences
CEPHALOSPORIN

2. CEPHALOSPORIN
 Cephalosporin-C was isolated by newton & Edward Abraham.
 Cephalosporin are B-lactam antibiotic containing B-lactam ring fuse with thiazine
heterocyclic group.
 Cephalosprium species: Prepared semi synthetically. In 1945 Giuseppe Brotzu`s
discovered that cultures of Cephalosporium acremonium inhibited the growth
of a wide variety of Gram-positive and Gram-negative bacteria.
 He noticed that they are effective against salmonella typi (typhoid fever), which
had B-lactamases.

4.  First Generation Cephalosporins
Cephalexin, Cephradine, Cefadroxil, Cephalothin, Cefapirin
 Second Generation Cephalosporins
Cefaclor, Cefoxitin, And Cefuroxime.
 Third Generation Cephalosporins
Cefixime, Cepodoxime, And Ceftriaxone, Cefoperazone
 Fourth Generation Cephalosporins
Cefepime, Cefpirome, Cefquinome
 Fifth Generation Cephalosporins
Ceftobiprole, Ceftaroline, Ceftolozane
Classification of Cephalosporins
• First generation Cephalosporins are active against gram+ve bacterial strains, with
succeeding generations progressively more active gram-ve bacterial strains.
• Fourth generation Cephalosporins are extended spectrum antibiotics.

5. STRUCTURES AND ITS USES
Structure:
Uses :
1. First generation Cephalosporins
2. To treat infections caused by gram +ve bacteria.
3. To treat upper respiratory tract infections, ear, skin, urinary tract
and bone infections
CEPHALEXIN

6. CEFADROXIL
Structure:
Uses :
1. First generation Cephalosporins use to treat bacterial infections.
2. To treat infections of throat, skin and urinary tract.
3. Used to treat gram+ve bacterial infections

7. CEFIXIME
Structure:
Uses :
1. Cefixime is a Third Generation Cephalosporins.
2. It is effective against both gram+ve and gram -ve bacterial infections.
3. Cefixime is resistant towards B-lactamase enzyme.
4. Used to treat typhoid fever and biliary tract infections.

8. CEFAPIRIN (cefapyridine)
Structure:
Uses :
1. Cefapirin is a first generation cephalosporin.
2. Cefapirin is combined with prednisolone to use in cattle for
maintaining intramammary glands and its production of milk.
3. Cefapirin acts as a intrauterine preparation in cattle.
4. Cefapirin has been banned for usage on human beings.

9. CEFUROXIME (cefutroxime)
Structure:
Uses :
1. Cefuroxime is a second generation cephalosporin used to treat gram -ve
bacterial infections.
2. Cefuroxime is the safest antibiotic during prengnancy.
3. Used to treat tonsillitis, laryngitis, bronchitis, throat infection, pneumonia,
gonorrhea, urinary tract infection caused by susceptible bacteria.

10. MECHANISM OF ACTION
 Cephalosporins interferes with synthesis of bacterial cellwall.
 Cellwall is composed of peptidoglycan layer, which consist of two amino
sugars.
1. N-Acetyl muramic acid (NAcM)
2. N-acetylglucosamine (NAcM)
 Peptidoglycan residues are linked together forming long strands & UDP
is split off.
 Then the cleavage of terminal-D alanine of the peptide occurs by
transpeptidase enzyme. This process is called transpeptidation.
 The cross bringing provides necessary strength to bacterial cellwall.

11. β-lactam antibiotics inhibit the transpeptidase enzyme so that
cross-linking does not takes place.
This leads to formation of cellwall deficient bacteria and causes
shrinkage of the bacterial cell.
Cephalosporins shows bactericidal action.

12. SIDE EFFECTS AND TOXICITY
• Pain and inflammation at injection site
• Diarrhoea
• Hypersensitivity reaction
• Nephrotoxicity
• Bleeding
• Pain on IM injection Eg: Cefalothin
• Nausea and vomiting
• Colitis
• Disulfiram like effects