Chemical Structure:
C15H15NO2
Mechanism of Action:
As a non-selective COX inhibitor, mefenamic acid reduces prostaglandin synthesis, leading to decreased inflammation and pain.
Structural Activity Relationship (SAR) of Mefenamic Acid
1.Anthranilic Acid Derivative:
Mefenamic acid is derived from anthranilic acid (2-aminobenzoic acid).
This structure is crucial for the biological activity of fenamates.
2.Carboxylic Acid Group:
The carboxylic acid group is essential for the anti-inflammatory activity.
It's necessary for binding to the COX (cyclooxygenase) enzymes, inhibiting the synthesis of prostaglandins.
3.Substitutions on the Benzene Ring:
The substitutions on the benzene ring, particularly the presence of a methyl group in the para position, contribute to its anti-inflammatory and analgesic activities.
4.Amine Substitution:
The presence of an amine group in the ortho position relative to the carboxylic acid group is a characteristic feature of fenamates.
The nature of this substitution can influence the drug's potency and pharmacokinetic properties.
Synthesis of Mefenamic Acid
The synthesis of mefenamic acid can be summarized through the following chemical reaction:
Synthesis from 2-Aminobenzoic Acid:
2-Aminobenzoic acid + 2-Methoxyethanol → Intermediate
Intermediate + Methyl Bromide → Mefenamic Acid
In practice, this synthesis involves several steps including protection of the amino group, alkylation, and then deprotection of the amino group. Each step requires specific reaction conditions such as temperature, pH, and the use of catalysts or reagents.
Uses:
It's particularly effective for menstrual pain and also used for general pain relief and anti-inflammatory purposes.
Side Effects:
Side effects include gastrointestinal issues, risk of ulceration and bleeding, renal impairment, and hypersensitivity reactions.