Dibucaine

Structure

• Dibucaine Chemical Structure – C20H29N3O2

Mode of action

• The sodium channels in the membrane of neuronal cells are reversibly bound and deactivated by dibucaine.

Structure-Activity Relationship (SAR) of Dibucaine

• Dibucaine is a potent local anesthetic of the amide type, used topically to reduce pain and discomfort.

Its SAR includes:

1. Amide Linkage:

• Unlike ester local anesthetics like procaine, dibucaine is an amide.

• This amide linkage is more resistant to hydrolysis, contributing to its longer duration of action and decreased risk of allergic reactions compared to ester anesthetics.

1. Aromatic Rings:

• The presence of two aromatic rings increases the lipophilicity of the molecule, facilitating its penetration into nerve membranes, which is essential for local anesthetic activity.

1. Quinoline Ring System:

• Dibucaine contains a quinoline moiety, which is a significant contributor to its high potency and long duration of action.

1. Tertiary Amine:

• The tertiary amine is essential for binding to the sodium channels in nerves, inhibiting depolarization and nerve impulse conduction.

• The nature and structure of this amine influence the drug's pharmacokinetic properties.

1. Alkyl Chain Length:

• The length of the alkyl chain linked to the amine affects the potency and toxicity of the drug.

• In dibucaine, this is optimally balanced for high efficacy with relatively lower toxicity.

Here is the mind map illustrating the Structure-Activity Relationship (SAR) of Dibucaine

Synthesis of Dibucaine

• The synthesis of Dibucaine involves multiple steps, but a key step is the formation of the amide bond, typically represented as:

Formation of the Amide Bond:

• 2C17​H19​N2​O + C4​H9​NO → C21​H29​N3​O2​

• In this reaction, a quinoline derivative (C17H19N2O) is reacted with N-butoxyethylamine (C4H9NO) to form Dibucaine (C21H29N3O2).

• This synthesis is an oversimplified representation and involves several intermediate steps, including the formation of the quinoline structure and careful handling of reactants due to their potential toxicity. The specific conditions, such as temperature, solvents, and catalysts, are crucial for the yield and purity of dibucaine.

Uses

• Dibucaine is used to treat conditions like sunburn, insect bites, minor cuts, etc. that cause discomfort and irritation.

• Group is crucial.