Scopolamine (hyoscine)

IUPAC nomenclature

(–)-(S)-3-Hydroxy-2-phenylpropionic acid (1R,2R,4S,5S,7α,9S)-9-methyl-3-oxa-9-azatricyclo[3.3.1.0^2,4]non-7-yl ester

Classification

Scopolamine is a acetylcholine antagonist-muscarinic antagonist.

Physiochemical Properties

Mechanism of Action

Scopolamine interfere with the transmission of the nerve impulses by Ach in the parasympathetic nervous system. It particularly acts for the vomiting center. [1]

Structure Activity Relationship

• Either R₁ or R₂ must be heterocyclic or carbocyclic.
• The R₃ group can be hydrogen, hydroxyl, hydroxymethyl or amide.
• Most protect derivatives has X as an ester.
• X can also be either oxygen or absent completely.
• The N substituent can be quaternary ammonium salt or tertiary amine or both with different alkyl groups.
• Maximum potency obtained when the distance between the ring substituted carbons is 2 carbon units.

Method of synthesis

A modified Robinson-Schopf reaction or [4+3] cycloaddition can help in synthesizing the scopolamine. [2]

Therapeutic Uses

Scopolamine is used for:

• Prevention of nausea
• Prevention vomiting

  Side Effects

Side effects of scopolamine are:

• Blurred vision
• Widened pupils
• Dry mouth
• Drowsiness
• Decreased sweating
• Constipation
• Itching and redness of skin

MCQ

Q.1 Maximum potency obtained of scopolamine when the distance between the ring substituted carbons is?

a) 1 carbon unit

b) 2 carbon unit

c) 3 carbon unit

d) 4 carbon unit

Q.2 Correct sequence for the True/False for correct IUPAC names of the drug can be?

• Bethanchol: 2-(Carbamoyloxy)-N,N,N-trimethylpropan-1-aminium.
• Glycopyrollate: (–)-(S)-3-Hydroxy-2-phenylpropionic acid (1R,2R,4S,5S,7α,9S)-9-methyl-3-oxa-9-azatricyclo[3.3.1.02,4]non-7-yl ester
• Scopolamine: (1,1-dimethylpyrrolidin-1-ium-3-yl) 2-cyclopentyl-2-hydroxy-2-phenylacetate
• Propranolol: (RS)-1-(1-methylethylamino)-3-(1-naphthyloxy)propan-2-ol.

a) FTTF

b) FFFT

c) TFFT

d) TTTT

Q.3 Physical appearance of Hyoscine is?

a) White crystalline powder

b) Viscous liquid form

c) Red crystals

d) Granular appearance

Q.4 Scopolamine produces effect on?

a) Nicotinic receptors

b) Muscarinic receptors

c) Both nicotinic and muscarinic receptors

d) None of the above

Q.5 Which amongst the following is a therapeutic use of drug Scopolamine?

a) Treatment of peptic ulcers

b) Treatment of Blurred vision

c) Prevention of nausea and vomitting

d) None of the above

Q.6 Which of the following drug and their classification are correct?

I. Bethanchol: Cholinergic agonist

II. Glycopyrollate: Acetylcholine antagonist

III. Scopolamine: Nicotinic receptors antagonist

IV. Propranolol: α-adrenergic antagonist

a) I , III

b) I , IV

c) III

d) I, II

Q.7 Number of chiral carbons scopolamine having?

a) 0

b) 3

c) 6

d) 9

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ANSWERS

1-b

2-c

3-b

4-b

5-c

6-d

7-a

REFERENCES