Zonisamide 68291-97-4 — China API Manufacturer | USP/EP/JP R&D to Production

China Manufacturing Landscape for Zonisamide

Zonisamide (CAS 68291-97-4) is a sulfonamide anticonvulsant used as adjunctive therapy in the treatment of partial seizures in epilepsy, with additional off-label applications in neuropathic pain, migraine prophylaxis, and Parkinson’s disease. Originally developed in Japan, Zonisamide has been adopted into epilepsy treatment guidelines worldwide and is available as a generic medication in most major pharmaceutical markets. Chinese API manufacturers have established efficient synthesis capabilities for Zonisamide, providing generic pharmaceutical companies globally with a reliable source of this important antiepileptic API at competitive competitive pricing.

China’s chemical synthesis infrastructure is ideally suited for Zonisamide production, with established domestic supply chains for the key starting materials including 1,2-benzisoxazole derivatives and sulfonyl chloride reagents. Our production facility operates dedicated Zonisamide production lines with annual capacity sufficient to serve a significant share of the global generic market, supported by process chemistry expertise developed over more than a decade of continuous commercial production.

Manufacturing Process & Facility

Zonisamide synthesis follows a well-optimized chemical route involving construction of the 1,2-benzisoxazole heterocyclic ring system from appropriately substituted salicylaldehyde or hydroxylamine precursors, followed by introduction of the methanesulfonamide functional group at the 3-position. Key synthetic steps include cyclization to form the isoxazole ring, selective functionalization of the methyl group at C-3, and sulfonamide bond formation through reaction with methanesulfonyl chloride under controlled conditions. The final product is obtained through recrystallization from optimized solvent systems to achieve pharmacopeial-grade purity and the required crystalline form.

The manufacturing facility includes glass-lined reactors (500 L to 5,000 L), automated temperature and pH control systems, centrifugal filtration equipment, vacuum dryers, and dedicated milling and sieving stations for particle size control. Quality control laboratories are equipped with HPLC, GC, IR, UV-Vis, and Karl Fischer instrumentation. The facility operates under NMPA certification with annual Zonisamide production capacity exceeding 100 metric tons, with current utilization supporting both contract supply and spot market demand.

Quality Standards & Multi-Pharmacopeial Compliance

Zonisamide API from our facility meets USP, EP, and JP pharmacopeial specifications simultaneously, enabling customers to serve all major regulated markets from a single qualified source. HPLC purity consistently exceeds 99.5%, with individual specified impurities controlled below 0.10% and total impurities below 0.30%. Assay by HPLC falls within 99.0-101.0% on the dried basis. Polymorphic form identity is confirmed by XRPD comparison against qualified reference patterns, and melting point determination provides additional identity verification.

Quality testing encompasses HPLC assay and related substances, polymorphic form by XRPD, residual solvents by headspace GC per ICH Q3C, elemental impurities by ICP-MS per ICH Q3D, loss on drying, sulfated ash, particle size distribution by laser diffraction, and microbial limits testing. Genotoxic impurity assessment per ICH M7 is performed with validated trace-level analytical methods. ICH Q1A stability data under long-term (25°C/60% RH) and accelerated (40°C/75% RH) conditions supports a 48-month retest period at room temperature storage.

Regulatory Documentation

Our Zonisamide regulatory documentation includes US FDA Type II Drug Master File, EU ASMF, and PMDA-compatible documentation for Japanese market filings. CTD Module 3.2.S packages include complete manufacturing process descriptions, starting material specifications and qualification, control strategy documentation, analytical method validation reports, and stability data. ICH M7 genotoxic impurity assessment and nitrosamine risk evaluation documentation are provided per current regulatory requirements. quality certificates, site master files, inspection history documentation, and WHO Prequalification-compatible packages are available. We provide ongoing regulatory support including timely responses to deficiency queries from reviewing authorities.

Packaging & Logistics

Zonisamide API is packaged in double PE bag-lined fiber drums in standard configurations of 10 kg, 25 kg, and 50 kg net weight. HDPE containers for smaller quantities (1 kg, 5 kg) are available for development and evaluation purposes. The product is stable at controlled room temperature and does not require cold chain management, enabling cost-effective sea freight for bulk commercial shipments (20-30 days transit to major destination ports). Air freight is available for urgent orders with 5-10 business day international delivery. Complete export documentation including CoA, MSDS, quality certificate, and customs classification assistance is provided as standard. FOB, CIF, and DDP Incoterms are supported.

Competitive Pricing & Supply Reliability

High-volume production capacity enables Zonisamide pricing that is among the most competitive globally for quality-certified material. Volume-tiered pricing with meaningful breaks at 500 kg, 1,000 kg, and 5,000 kg annual commitment levels rewards customer procurement planning. Standard lead times are 2-3 weeks from maintained inventory for quantities up to 1 metric ton, and 4-6 weeks for larger campaign orders. Our production scheduling flexibility allows for accommodation of seasonal demand patterns and expedited orders for customers with urgent supply requirements. Multi-year supply agreements with guaranteed allocation and indexed pricing are available for strategic customers.

Zonisamide Specifications