CYCLIZINE Synthesis, SAR, MCQ,Structure,Chemical Properties and Therapeutic Uses
Cyclizine
IUPAC nomenclature
1-benzhydryl-4-methyl-piperazine
Classification
- H1-receptor antihistamine
- Piperazine antihistamine
Physiochemical Properties
| S. NO. | PHYSICAL AND CHEMICAL PROPERTIES | |
| 1 | Molecular weight | 266.4 g/mol |
| 2 | Physical appearance | White or creamy white crystalline powder |
| 3 | Melting point | 105.5oC |
| 4 | Solubility | Soluble in alcohol and chloroform; slightly soluble in water; freely soluble in ether |
| 5 | Octanol/water partition coefficient | 3 |
| 5 | Presence of ring | Piperazine, phenyl |
| 6 | Number of chiral centers | Not present |
Mechanism of Action
- Cyclizine blocks the action of histamine on the receptors present at vomiting center (CTZ).
- Cyclizine also have anti-cholinergic properties, thus, it also blocks muscarinic receptors.
Structure Activity Relationship
Structure activity of piperizine antihistamines can be summarized as:
- These are the derivatives of ethylene diamines.
- The connecting moiety is CHN group
- Primary structural difference is nature of para aromatic ring substituent
- These are moderately potent.
- Slow onset of action
- Low incidence of drowsiness
- They also exhibit peripheral and central antimuscarinic activity.
Method of synthesis
Alkylation of 1-methylpiperazine with benzhydrylbromide gives cyclizine. [1]
Medicinal Uses
Cyclizine is used for treatment of:
- Nausea
- Vomiting
- Dizziness
- Motion sickness
Side Effects
Side effects of cyclizine are:
- Difficult in urination
- Pounding heartbeats
- Lightheadedness
- Drowsiness
- Weakness
- Loss of coordination
- Nausea
- Dry mouth
- Constipation
- Blurred vision
- Difficult breathing
- Signs of allergic recations
- Swellings
MCQs
Q.1 Correct statements from the following related with the physicochemical properties of drug cyclizine are?
I. Molecular weight: 266.4 gm/mol
II. Appearance: White or creamy white crystalline powder
III. Melting Point: 105.5oC
IV. Solubility: Soluble in alcohol
a) I, II, IV
b) I, III, IV
c) II, IV
d) I, II, III, IV
Q.2 Match the following of the drugs with their correct IUPAC names.
| i. Cyclizine | A. (RS)-6-(Difluoromethoxy)-2-[(3,4-dimethoxypyridin-2-yl)methylsulfinyl]-1H-benzo[d]imidazole |
| ii. Lansoprazol | B. 2-[[3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl]methylsulfinyl]-1H-benzimidazole |
| iii. Famotidine | C. 3-[({2-[(diaminomethylidene)amino]-1,3-thiazol-4-yl}methyl)sulfanyl]-N-sulfamoylpropanimidamide |
| iv. Pentoprazole | D. 1-benzhydryl-4-methyl-piperazine |
a) i-D, ii-B, iii-C, iv-A
b) i-A, ii-B, iii-D, iv-C
c) i-B, ii-C, iii-A, iv-D
d) i-A, ii-C, iii-D, iv-B
Q.3 Cyclizine has actions on?
I. Vomiting center
II. Cholinergic receptors
III. Muscarinic receptors
IV. Nicotinic receptors
a) I, III
b) I, IV
c) I, II, III
d) I
Q.4 Correct sequence for True/false for the classification of the drug can be?
- Cyclizine: H1-receptor antihistamine drug
- Haloperidol: Inhalational anesthetics
- Codeine: Narcotic analgesic
- Triclofos sodium: Sedative-hypnotics
a) TFTF
b) TTTT
c) FFTF
d) TFFT
Q.5 Piperizine antihistamine drugs are derivatives of?
a) Ethylene diamine
b) Piperidine
c) Benzodiazepine
d) Phenothiazine
Q.6 Type of rings present in the structure of cyclizine?
I. Pyridine
II. Piperazine
III. Phenyl
IV. Benzodiazepine
a) I, IV
b) I
c) II, III
d) II
Q.7 Side effect of drug Cyclizine is/are?
a) Difficulty urination
b) Loss of coordination
c) Nausea
d) All of the above
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ANSWERS
1-d
2-a
3-c
4-b
5-a
6-c
7-d
REFERENCES
[1] Vardanyan R, Hruby V. Synthesis of essential drugs. Elsevier; 2006 Mar 10.