Dexlansoprazole

IUPAC nomenclature

(R)-(+)-2-([3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl]methylsulfinyl)-1H-benzo[d]imidazole

Classification

• Proton pump inhibitors

Physiochemical Properties

Mechanism of Action

• Dexlansoprazole is a prodrug which requires protonation via an acidic environment to get activated form Sulphenamide.
• Sulphenamide covalently binds with cystien residues via disulfide bridges on the α subunit of H/K ATPase enzyme system.
• Thereby it inhibits the H⁺/K⁺ ATPase pump which in turn inhibits the gastric acid secretion or formation of hydrochloric acid in parietal cells

Structure Activity Relationship

General structure activity of Heteroaryl- and heterocyclyl-substituted imidazo[1,2-a]Pyridine derivatives acting as acid pump antagonists can be summarized as:

• The inhibitory property of drugs depends on hydrophobic group substituted at the left side ortho-position of the phenyl ring.
• Increase in hydrophobic value increases the activity.
• Increasing the GTCI value decreases the activity.
• Small molecule substitutions may participate in hydrophobic interaction as well as steric interactions. [1]

Method of synthesis

TAP’s group synthesized the Dexlansoprazole through the following scheme: [2]

Medicinal Uses

Dexlansoprazole is used for treatment of:

• Stomach ulcers
• Active duodenal ulcers
• Active benign gastric ulcer
• GERD
• Erosive esophagitis
• Zollinger-Errison syndrome

Side Effects

Side effects of Dexlansoprazole are:

• Abdominal pain
• Nausea
• Constipation
• Headache
• Low magnesium blood level
• Irregular heartbeat
• Muscle spasms
• Seizures
• Lupus
• Diarrhea
• Blood in stool

MCQs

Q.1 Mechanism of action of Dexlansoprazole drug includes?

a) Protonation into sulphenamide

b) Conversion into hydroxyzine

c) Vasoconstriction

d) Agonist effects H1 receptor for Histamine

Q.2 Medicinal use of drug Dexlansoprazole is/are?

a) Stomach ulcers

b) Watery eyes

c) Sneezing

d) Hives

Q.3 Select the correct option from below related with the General structure activity of Heteroaryl- and heterocyclyl-substituted imidazo[1,2-a]Pyridine derivatives acting as acid pump antagonists-

a) The inhibitory property of drugs depends on hydrophobic group substituted at the left side ortho-position of the phenyl ring.

b) Increase in hydrophobic value decreases the activity.

c) Increasing the GTCI value increases the activity.

d) All of the above

Q.4 Number of chiral carbons present in the structure of Dexlansoprazole is?

a) 0

b) 1

c) 2

d) 3

Q.5 Correct sequence for the True/False for the physiochemical properties of the drug dexlansoprazole can be?

• Molecular weight: 952.3 gm/mol
• Physical appearance: Yellow crystalline powder
• Octanol/water partition coefficient: 2.38

a) TTT

b) TFT

c) FFT

d) TFF

Q.6 Correct statements for the IUPAC nomenclatures of the drugs are?

I. Dexlansorazole: 2-methyl-3-[2-[(5-methyl-1H-imidazol-4-yl)methylsulfanyl]ethyl]guanidine

II. Loxapine: (3-methylpyridin-2-yl]methylsulfinyl)-1H-benzo[d]imidazole.

III. Gluthethmide: 4-Chlorophenyl)phenylmethyl-1-piperazinyl]ethoxy]acetic acid

IV. Tolazoline: 2-Benzyl-4,5-dihydro-1H-imidazole

a) I, II

b) III, IV

c) IV

d) I, II, III, IV

Q.7 Match the following drugs with their correct classifications-

 a) i-A, ii-C, iii-D, iv-B

b) i-D, ii-A, iii-C, iv-B

c) i-D, ii-B, iii-A, iv-C

d) i-B, ii-D, iii-A, iv-C

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ANSWERS

1-a

2-a

3-a

4-a

5-c

6-c

7-a

REFERENCES