Longest acting sulphonamide is -
Sulphadiazine
Sulfacytidine
Sulfamethoxazole
Sulfadoxine
Ans, is 'd' i.e., Sulfadoxine Sulfonamideso Sulfonamides are bacteriostatic and act by inhibiting folic acid synthesis by inhibiting enzyme folate synthatase.o Bacteria synthesize their own folic acid of wTtich para aminobenzoic acid (PABA) is a constituent - Sulfonamides, being structural analogues of PABA, inhibit bacterial folate synthase competitively.o Sulfonamides are not effective in presence of pus and tissue extract because - (1) Pus contains purines and thymidine which decrease bacterial requirement for folic acid and (2) Pus is rich in PABA.Classification1. Short acting - Sulfadiazine, Sulfisoxaxole, Sulfamethizole, Sulfacystine.Intermediate acting - Sulfamethoxazole.Long acting - Sulfadoxine, Sulfamethopyrazine.Topical Sulfonamides - Sulfacetamide sodium, Mafenide, silver sulfadiazine.Sulfonamide for RA and ulcerative colitis - Sulfasalazine.o Sulfadoxine is Longest acting whereas sulfacytidine is shortest acting sulphonamide.
Anti Microbial