Local Anesthetics | SAR of Local anesthetics | synthesis of benzocaine , dibucaine , procaine

DEPTH OF BIOLOGY・2 minutes read

Local anesthetic blocks nerve conduction to prevent pain signals from reaching the brain, allowing minor surgeries to be done without pain. General anesthesia affects the entire body and leads to unconsciousness, while local anesthesia targets specific areas, making it safer for patients with poor health.

Insights

  • Local anesthetics like Lidocaine and Procaine stop nerve conduction in a specific area, preventing pain signals from reaching the brain, allowing minor surgeries to be performed without pain.
  • The lecture extensively covers the structure-activity relationship of local anesthetics, emphasizing the importance of lipophilic aryl groups and hydrophilic amino alkyl groups in their effectiveness, with specific syntheses like Benzocaine, Procaine, and Dibene highlighted in the syllabus.

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  • How does local anesthesia work?

    Local anesthetic blocks nerve conduction to stop pain signals.

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Summary

00:00

Local Anesthetic: Mechanism and Application

  • Today's lecture focuses on local anesthetic, covering its introduction, classification, drugs included, mechanism of action, structure-activity relationship, and three syntheses mentioned in the syllabus.
  • The syllabus includes the SR of local anesthetic, benzoic acid derivative, amino benzoic acid derivative, lidocaine, and miscellaneous drugs, with a specific emphasis on three syntheses: Benzocaine, Procaine, and Dibene.
  • Local anesthetic stops nerve conduction in a specific area, allowing minor surgeries to be performed without pain.
  • Anesthetic agents block nerve conduction, preventing pain signals from reaching the brain, thus eliminating pain sensation.
  • Local anesthetic causes a temporary loss of feeling in a small area, with the patient remaining awake but devoid of sensation in the treated area.
  • General anesthesia affects the entire body, leading to unconsciousness, while local anesthesia targets a restricted area, maintaining consciousness.
  • General anesthesia requires careful monitoring of vital functions due to its potential risks, while local anesthesia poses minimal risk to vital organs.
  • General anesthesia is high-risk for patients with poor health, while local anesthesia is safer and suitable for such individuals.
  • Local anesthesia is preferred for minor surgeries, while general anesthesia is used for major surgeries.
  • Examples of general anesthetics include opiates and gases, while local anesthetics include Lidocaine and Procaine.
  • Anesthetics, whether local or general, work by halting nerve conduction, ensuring pain signals are not transmitted to the brain.

14:03

"Neurons, Signals, and Local Anesthetics Explained"

  • Receptors in nerves receive signals, leading to the generation of an action potential and depolarization.
  • Signal transmission in neurons involves the generation of action potential and depolarization due to drug reception.
  • Depolarization opens sodium channels, allowing sodium to move from extracellular to intracellular fluid.
  • Pain signal triggers dendrite to receive the signal, leading to action potential generation and depolarization.
  • Signals from depolarization are sent to the brain through sensory neurons, indicating pain sensation.
  • Local anesthetic is needed to shut down sensory neurons to stop pain signals from reaching the brain.
  • Neurons have cell membranes made of phospholipids, with sodium channels and local anesthetic receptors.
  • Neurons at rest have closed sodium channels and M gates due to no signal generation.
  • Local anesthetic like BH drug crosses the axonal membrane, dissociates, and blocks sodium channels.
  • Local anesthetic stops sodium influx, preventing depolarization and pain signal transmission to the brain.

27:17

Local Anesthetics: Classification, Mechanism, and Synthesis

  • Injectable anesthetics are used in minor surgeries, such as Procaine, which is a surface anesthetic.
  • The lecture covers the onset potency and factors affecting the duration of action of local anesthetics.
  • Classification of local anesthetics is discussed, along with their mechanism of action.
  • General conditions, signal transmission, and the difference between general and local anesthetics are explained.
  • Local anesthetics are classified into ester and amide types based on their structure.
  • The structure-activity relationship of local anesthetics involves lipophilic aryl groups and hydrophilic amino alkyl groups.
  • The bridging between lipophilic and hydrophilic groups in local anesthetics is crucial for their effectiveness.
  • The presence of an amino alkyl group does not affect the anesthetic activity but aids in making water-soluble salts.
  • The aryl group's direct attachment to the carbonyl group enhances the local anesthetic effect.
  • Synthesis of benzocaine involves nitration, oxidation, acidification, and reduction steps to produce the final product.

40:31

Chemical reactions produce procaine hydrochloride and indoline.

  • Para amino benzoic acid reacts with two hydroxy tri ethyl amine in the presence of H2SO4 and heat to produce procaine base.
  • The reaction involves the removal of water to facilitate the formation of procaine, with the addition of CH2NCH2 and C2H5.
  • Procaine hydrochloride is formed when procaine base reacts with HCl.
  • Indoline 23 dron reacts with acid elution to form indoline 23 dan, involving the addition of nitrogen and double bonds to create the final product.
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