Sulthiame, also known internationally as Sultiame, is a synthetic sulfonamide active pharmaceutical ingredient with anticonvulsant and carbonic anhydrase-inhibiting properties. It is used as an antiepileptic medicine in certain countries, particularly for specific seizure disorders. PubChem and NIST identify Sulthiame with CAS No. 61-56-3, molecular formula C₁₀H₁₄N₂O₄S₂, and molecular weight 290.36 g/mol.
Sulthiame is chemically different from the classical antibacterial sulfonamides. Although it contains a sulfonamide group, its principal pharmaceutical role is as a carbonic anhydrase inhibitor and anticonvulsant, rather than as an antibacterial agent.
The chemical name of Sulthiame is 4-(1,1-dioxothiazinan-2-yl)benzenesulfonamide. Its molecular structure contains a benzenesulfonamide group connected to a cyclic sulfamide/sultam structure. NIST reports a molecular weight of 290.359 g/mol, while PubChem reports 290.4 g/mol.
Sulthiame is also known by the synonyms Sultiame, Sulthiamine, Sultiam, Sultiamum, Ospolot, Trolone and Riker 594. FDA GSRS identifies the substance with UNII I00Q766CZ2.
Sulthiame is a crystalline solid. Published pharmaceutical analytical literature describes it as white crystals or crystalline powder, highly soluble in N,N-dimethylformamide, freely soluble in n-butylamine, slightly soluble in methanol and very slightly soluble in water.
The API has an InChIKey of HMHVCUVYZFYAJI-UHFFFAOYSA-N. PubChem reports a topological polar surface area of 114 Ų and six hydrogen-bond acceptors.
Sulthiame is an antiepileptic drug used for the management of certain seizure disorders. Published clinical literature describes its use in partial and generalized seizures, including childhood epilepsy syndromes such as epilepsy with centrotemporal spikes.
Its pharmacological activity is closely associated with inhibition of carbonic anhydrase. This distinguishes Sulthiame from antibacterial sulfonamides such as Sulfanilamide and Sulfamethoxazole.
Sulthiame inhibits carbonic anhydrase, reducing the enzyme-mediated conversion between carbon dioxide and bicarbonate. The resulting changes in intracellular and extracellular acid-base balance can influence neuronal excitability and contribute to its anticonvulsant activity. Experimental studies have demonstrated that Sulthiame can reduce intracellular pH and epileptiform neuronal activity.
A validated reversed-phase HPLC method for Sulthiame has been published using a C18 column with water:methanol 70:30 v/v, UV detection at 210 nm, and a reported separation time of approximately 2.83 minutes. The method showed linearity from 20–200 µg/mL, with an LOD of 4.2 µg/mL and LOQ of 9.5 µg/mL. These are analytical-method validation parameters and must not be treated as API release specifications.
I could not verify a current universal USP/BP/Ph. Eur. numerical API release monograph for Sulthiame. Therefore, assay, individual impurities, total impurities, water content and residue-on-ignition limits should not be fabricated.
Sulthiame API manufacturing involves controlled chemical synthesis followed by purification, crystallization and drying. Appropriate process controls should address chemical identity, assay, related substances, residual solvents, moisture and physical characteristics.
Validated chromatographic and spectroscopic methods can be used for release and stability testing.
Sulthiame is a crystalline solid with molecular weight approximately 290.36 g/mol. Published analytical literature reports very low water solubility and greater solubility in selected organic solvents.
Published supplier/reference data report melting ranges around 177–182°C, depending on the material and source. A pharmaceutical analytical paper identifies the substance as crystalline material, while commercial reference data report approximately 180–182°C.
Sulthiame should be stored in suitable pharmaceutical-grade, tightly closed packaging that protects the API from moisture, contamination and environmental exposure. Storage conditions should ultimately be based on validated stability data for the manufactured API.
Typical API documentation may include a Certificate of Analysis (CoA), specification sheet, Safety Data Sheet (SDS), analytical method information, batch documentation, impurity profile, residual-solvent information and applicable regulatory documentation.
A qualified Sulthiame API manufacturer should maintain controlled synthesis, validated analytical procedures and complete batch traceability. Particular attention should be given to identity, assay, related substances, residual solvents and physical properties to ensure consistent pharmaceutical-grade material.
| Parameter | Specification |
|---|---|
| Appearance | white to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.3–101.7% |
| Melting Point | 180–182°C |