Niflumic acid

IUPAC nomenclature

2-{[3-(trifluoromethyl)phenyl]amino}nicotinic acid

Classification

• NSAID
• Anthranylic acid derivatives

Physiochemical Properties

Mechanism of Action

Niflumic acid acts as an anti-inflammatory drug and reduces pain through:

• Inhibition of COX-2 enzyme
• Inhibition of phospholipase A2

Structure Activity Relationship

General SAR for anthranylic acid derivatives can be summarized as follows:

• Activity decreases when substitution on anthranilic acid ring.
• Activities due to substitution on the N-aryl ring follows the general order m > o > p.
• For disubstitution products, activity was found to be maximum when o and m positions are substituted near to each other on the N-aryl ring.
• Substitutions on the N-aryl ring with such groups which leads the ring to be noncoplanar with the anthranilic acid ring increases the binding of the drug and hence, increases the activity (meclofenamic acid being more active than flufenamic acid).
• NH-moiety of the anthranilic ring is important for the activity of the drug, and replacement of NH- moiety with O, CH₃, S, SO₂, N-CH₃ or N-COCH₃ groups decreases the activity of drug.
• Position of the acidic function is important for the activity and not the nature of acidic function.
• Replacement of carboxylic acid function with isosteric tetrazole function has no significant effect on the activity of compound.[1]

Method of synthesis

Reaction of 2-aminonicotinic acid with 1-bromo-3-trifluoromethylbenzene produces Niflumic acid. [2]

Therapeutic Uses

Niflumic acid is used for:

• Treatment of pain due to rheumatoid arthritis 

Side Effects

Side effects of Niflumic acid are:

• Diarrhea
• GI ulceration
• Diffuse pain in abdomen
• Nausea
• Vomiting 

MCQs

Q.1 Mechanism of action of Niflumic acid is due to?

a) Inhibition of COX-1

b) Inhibition of COX-2

c) Inhibition of muscarinic receptors

d) Inhibition of nicotinic receptors

Q.2 Therapeutic use of drug Niflumic acid is/are?

a) Treatment of Pain due to rheumatoid arthritis

b) Treatment of Anemia

c) Treatment of ulceration

d) All of the above

Q.3 Which amongst the following are the correct statements with respect to the SAR of Anthranylic acid derivatives?

I. For disubstitution products, activity was found to be maximum when o and m positions are substituted near to each other on the N-aryl ring.

II. Substitutions on the N-aryl ring with such groups which leads the ring to be noncoplanar with the anthranilic acid ring increases the binding of the drug and hence, increases the activity (meclofenamic acid being more active than flufenamic acid).

III. NH-moiety of the anthranilic ring is important for the activity of the drug, and replacement of NH- moiety with O, CH₃, S, SO₂, N-CH₃ or N-COCH₃ groups decreases the activity of drug.

 a) I, II, III

b) I, II

c) I, III

d) II, III

Q.4 Number of chiral centers present in the structure of Niflumic acid is?

a) 0

b) 3

c) 1

d) 2

Q.5 Correct sequence for the True/False for the physiochemical properties of the drug Niflumic acid?

• Molecular weight:282.22gm/mol
• Physical appearance: Solid
•  Melting point: 203⁰C
• Octanol/water partition coefficient: 4.43

a) TFFT

b) TTTT

c) TTFF

d) FFFF

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

I. Niflumic acid: 2-{[3-(trifluoromethyl)phenyl]amino}nicotinic acid

II. Methadone: (RS)-6-(dimethylamino)-4,4-diphenylheptan-3-one

III.  Anilridine: Ethyl 1-[2-(4-aminophenyl)ethyl]-4-phenylpiperidine-4-carboxylate

IV. Desflurane: 2-(difluoromethoxy)-1,1,1,2-tetrafluoroethane

a) I, II

b) I, II, III, IV

c) I, IV

d) I, II, III, IV 

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

 a) i-A, ii-D, iii-B, iv-C

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

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

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

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ANSWERS

1-b

2-a

3-a

4-a

5-b

6-b

7-c

REFERENCES