Classification of Sulphonamides

CLASSIFICATION

Sulphonamides can be classified in various ways:

On the basis of the site of action

·Sulphonamides for general infection: Sulphanilamide, Sulphapyridine, Sulphadiazine, Sulphamethoxacine, Sulphamethoxazole.

·Sulphonamides for urinary tract infections: Sulphaisoxazole, Sulphathiazole.

·Sulphonamides for intestinal infections: Phthalylsulphathiazole, Succinyl sulphathiazole, Sulphasalazine.

·Sulphonamides for local infections: Sulpahacetamide, Mafenamide, Silver sulphadiazine.

·Sulphonamides for dermatitis: Dapsone, Solapsone.

·Sulphonamides in combination: Trimethoprim with Sulphamethoxazole.

On the basis of the pharmacokinetic properties

·Poorly absorbed sulphonamides (locally acting sulphonamides)—Sulphasalazine, Phthalylsulphathiazole, Sulphaguanidine, Salicylazo sulphapyridine, Succinyl sulpha thiazole.

·Rapidly absorbed and rapidly excreted (systemic sulphanamides): Sulphamethoxazole, Sulphaisoxazole,

Sulphadiazine, Sulphadimidine, Sulphafurazole, Sulphasomidine, Sulphamethiazole, Sulphacetamide Sulphachlorpyridazine.

·Topically used sulphonamides: Sulphacetamide, Mafenide, Sulphathiazole, Silver sulphadiazine.

On the basis of the pharamacological activity

·Antibacterial agents:Sulphadiazine, Sulfisoxazole.

·Drugs used in dermatitis: Dapsone.

On the basis of the duration of action

·Extra long-acting sulphonamides (half-life greater than 50 h): Sulphasalazine, Sulphaclomide, Sulphalene.

·Long-acting sulphonamides (half-life greater than 24 h):Sulphadoxine, Sulphadimethoxine, Sulphamethoxy pyridazine, Sulphamethoxydiazine, Sulphaphenazole, Sulphamethoxine.

·Intermediate-acting sulphonamides (half-life between 10–24 h): Sulphasomizole, Sulphamethoxazole.

·Short-acting sulphonamides (half-life less than 20 h): Sulphamethiazole, sulphaisoxazole.

·Injectables (soluble sulpha drugs): Sulphafurazole, Sulphadiazine, Sulphamethoxine.

On the basis of the chemical structure

·N-substituted sulphonamide:Sulphadiazine, Sulphacetamide, Sulphadimidine.

·N-4 substituted sulphonamides (prodrugs): Prontosil.

·Both N-1 and N-4 substituted sulphonamides: Succinyl sulphathiazole, Phthalylsulphathiazole.

·Miscellaneous: Mefenide sodium.

I. N-1 Substituted sulphonamides

a. Short-acting sulpha drugs

b. Intermediate-acting sulphonamides

c. Long-acting sulphonamides

d. Extra long-acting sulphonamides

II. N-4 substituted suphonamides

Prontosil

III. Both N-1 and N-4 substituted suphonamides

IV. Miscellaneous

a. Topically used sulphonamides

Mafenide

Silver sulphadiazine

Solapsone

b. Drugs used in combination with sulphonamides

Trimethoprim

Pyrimethamine