Longest acting oral sulphonamide is
Sulphadoxine is the longest acting orally absorbable drug. Mafenide is a topical drug.sulphadiazine and sulfacetamide are sho-acting oral drugsRef: KD Tripathi 6th ed .pg: 684
Sulphadoxine
Sulphadiazine
Sulphacetamide
Mafenide
All India exam