Intra-intestinal inactivation of antibiotics

Question 1

How to protect colonic microflora from resistance?

Answer 1

Avoid extensive use
Avoid close contact of antibiotic and colonic microflora
Intra-intestinal inactivation of residual antibiotic

Question 2

How do intra-intestinal inactivation work?

Answer 2

Intra-intestinal inactivating agent is co-administered with residual antibiotic.

• The absorption and pharmacokinetics of the antibiotic is not affected
• Inactivation is beyond the activation window
• The inactivating agent is released after the absorption window

Question 3

What are the 3 inactivation mechanisms?

Answer 3

• Enzymatic inactivation
• Inactivation by adsorption
• Inactivation by complexation

Question 4

Enzymatic inactivation properties

Answer 4

• Specific
• Permanent/irreversible
• Limited to specific classes
• Problems with stability in GIT

Question 5

How does enzyme inactivation work?

Answer 5

Beta lactamase loaded pectinate beads inactivate colonic beta lactams

• High concentration of beta lactamase found in faeces to inactivate residual antibiotic and protect gastrointestinal microbiata.
• Amoxicillin

Question 6

How does inactivation by adsorption work?

Answer 6

• Activated charcoal loaded zinc pectinate beads for intestinal inactivation of ciprofloxacin
• Ciprofloxacin absorption window in the duodenum