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• What is the structure of cephalosporins?

  They have a β-lactam ring fused to a dihydrothiazine ring

  
• How do cephalosporins compare to penicillins?

  They differ in potency, spectrum, and advantages
• What is the mechanism of action of cephalosporins?

  They inhibit the transpeptidase enzyme
• What are crucial structural components of cephalosporins?

  β-lactam ring, free carboxylic acid, fused ring system

  
• Why are modifications made to cephalosporins?

  • Improve acid stability
  • Enhance pharmacokinetics
  • Broaden spectrum of activity
  • Increase activity
  • Resistance to bacterial degradation
  • Better outer membrane penetration
  • Higher affinity to PBPs
  • Reduce allergy
  • Increase tolerance after administration
• What is the key intermediate for semi-synthetic cephalosporin synthesis?

  7-aminocephalosporonic acid (7-ACA)

  
• Why can't 7-ACA be obtained from fermentation?

  It cannot be obtained from hydrolysis of cephalosporin C

  
• What is the synthesis solution for 7-ACA?

  Chemical hydrolysis of cephalosporin C

  
• How are cephalosporins classified?

  • Based on spectrum of activity
  • Chemical sophistication
  • Chronology
• Name a first-generation cephalosporin.

  Cefazolin
• What is a notable issue with cephalothin?

  The alcohol is less active than the acetoxy group
• How was esterase stability improved in cephaloridine?

  By changing the acetoxy group to a pyridinium group
• What modifications improve oral absorption in cephalosporins?

  Adding a methyl group at position-3
• What is a characteristic of second-generation cephalosporins?

  Cephamycins have a methoxy group at position-7

  
• What do oximinocephalosporins do?

  Increase stability against β-lactamase enzymes
• What enhances outer membrane penetration in third-generation cephalosporins?

  Aminothiazole ring
• What is a feature of fourth-generation cephalosporins?

  They are zwitterionic and improve penetration
• What is a characteristic of fifth-generation cephalosporins?

  They target MRSA and MDRSP
• What factors affect the activity of cephalosporins?

  Ability to reach transpeptidase and stability to β-lactamases
• What is the summary of first-generation cephalosporins compared to penicillins?

  Better stability but poor oral availability
• What are the key points in the synthesis of cephalosporins?

  • Semi-synthetic procedures from 7-ACA
  • Requires activation of the side chain
  • Metabolic deacetylation lowers activity
  • 3-methyl groups increase oral availability

  
• What do methoxy groups at C-7 do in cephalosporins?

  They enhance activity and spectrum

  
• What is an example of a carbapenem?

  Thienamycin

  
• What is a characteristic of monobactams?

  They have a monocyclic β-lactam ring
• How do monobactams differ from penicillins?

  They have a different spectrum of activity
• What are the two major classes of β-lactamase enzymes?

  Classes A, C & D and Class B

  
• What is the role of metallo-β-lactamase enzymes?

  They are a major source of resistance

  
• What is clavulanic acid used for?

  It is a powerful inhibitor of β-lactamases
• What is a key feature of clavulanic acid's structure?

  Strained β-lactam ring
• What are key examples of β-lactamase inhibitors?

  Sulbactam and tazobactam
• What is the mechanism of action of avibactam?

  It is a reversible inhibitor of β-lactamases

  
• What is vaborbactam known for?

  It is a first-in-class β-lactamase inhibitor
• What is cycloserine?

  A miscellaneous cell-wall synthesis inhibitor