Drugs used in combination with sulphonamides

Antibacterial Sulphonamides - Synthesis and Drug Profile

Drugs used in combination with sulphonamides

i. Trimethoprim

Synthesis

Properties and uses: Trimethoprim is a white or yellowish-white powder, very slightly soluble in water and slightly soluble in ethanol. It is used as dihydrofolate reductase inhibitor, effective against chloroquine and pyrimethamine resistant strains of Plasmodium falsiparum.

Assay: Dissolve the sample in anhydrous acetic acid and titrate with 0.1 M perchloric acid. Determine the end-point potentiometrically.

Dosage forms: Co-trimoxazole intravenous infusion B.P., Co-trimoxazole oral suspension B.P., Paediatric co-trimoxazole oral suspension B.P., Co-trimoxazole tablets B.P., Dispersible co-trimoxazole tablets B.P., Paediatric co-trimoxazole B.P., Tablets trimethoprim oral suspension B.P., Trimethoprim tablets B.P.

ii. Pyrimethamine

Synthesis

Properties and uses: Pyrimethamine is a white crystalline powder or colourless crystals, practically insoluble in water, and slightly soluble in alcohol. It is used in combination with sulphadoxine for the treatment of malaria.

Assay: Dissolve the sample in anhydrous acetic acid by heating gently. Cool and titrate with 0.1 M perchloric acid. Determine the end point potentiometrically.

Dosage forms: Pyrimethamine tablets I.P., pyrime thamine tablets B.P.