Ipratropium Bromide

• Ipratropium Bromide is a short-acting anticholinergic bronchodilator with minimal systemic effects.
• Ipratropium Bromide treats asthma and COPD by relaxing airway muscles and easing breathing.

Formula:

• C₂₀H₃₀BrNO₃

Mechanism:

• Blocks M3 receptors in bronchial smooth muscle → bronchodilation
• Minimal CNS effect (doesn’t cross BBB)

Uses:

• COPD
• Asthma (adjunct)

Side Effects:

• Dry mouth
• Cough
• Bitter taste
• Nasal dryness

SAR of Ipratropium:

1. Quaternary ammonium group:

   • Restricts CNS access; enhances peripheral selectivity.

2. Tropane ring:

   • Essential for muscarinic receptor binding (core atropine-like structure).

3. Ester linkage:

   • Necessary for receptor affinity.

4. Substituted isopropyl group on nitrogen:

   • Improves selectivity for bronchial M3 receptors and increases duration of action.

5. Antagonistic effect:

   • Bulky substituents block receptor activation.

Synthesis Overview:

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