Sulfamethoxazole
Also known as: Bactrim, Septran, Septrin, Co-trimoxazole, Sulfatrim, Cotrim
CAS Number: 723-46-6
Sulfonamide antibacterial (folate synthesis inhibitor)
Pharmacopeia Standards
Mechanism of Action
Sulfamethoxazole is a structural analogue of para-aminobenzoic acid and competitively inhibits dihydropteroate synthase, blocking the first committed step of bacterial folate biosynthesis. Paired with trimethoprim, which inhibits dihydrofolate reductase downstream, it produces sequential blockade of the folate pathway and a synergistic bactericidal effect. Human cells take up preformed folate and are not affected by the dihydropteroate synthase step.
Technical Specifications
| Generic / INN Name | Sulfamethoxazole |
| CAS Registry Number | 723-46-6 |
| Molecular Formula | C10H11N3O3S |
| Molecular Weight | 253.28 g/mol g/mol |
| Typical Purity | 99.0-101.0% on dried basis (USP/EP); any individual impurity NMT 0.2% |
| Storage Conditions | Store in well-closed containers at 15-30 C, protected from light and moisture |
| Shelf Life | 60 months from date of manufacture |
| Category | Sulfonamides |
Specifications are indicative and intended for sourcing reference only. Always confirm against the supplier's Certificate of Analysis and the applicable pharmacopeial monograph before issuing a purchase specification.
Typical Applications
Co-trimoxazole tablets, dispersible paediatric tablets, oral suspensions and IV infusion concentrate; prophylaxis and treatment of Pneumocystis jirovecii pneumonia; veterinary sulfa-trimethoprim combinations.
Manufacturers (0+)
View all →Do you manufacture Sulfamethoxazole? Add your free listing and reach global buyers.
Add listing — FreeCan you supply Sulfamethoxazole? List as an authorised distributor or export house.
Register as traderEarn commission by connecting buyers with verified API suppliers. Free to join.
Become an agent