Clarithromycin CAS 81103-11-9 — China API Manufacturer | ChP/USP/EP/JP R&D to Production

Product Overview & China Manufacturing Landscape

Clarithromycin is a semi-synthetic macrolide antibiotic derived from erythromycin A, widely prescribed for respiratory tract infections, H. pylori eradication, and mycobacterial infections. With CAS number 81103-11-9 and molecular formula C₃₈H₆₉NO₁₃, clarithromycin is one of the highest-volume macrolide APIs in global pharmaceutical manufacturing. China is the world’s dominant producer, with over 20 NMPA-registered clarithromycin manufacturers and combined annual production capacity exceeding 4,000 metric tons — representing approximately 60-70% of global supply. Our manufacturing facility in Zhejiang Province operates within China’s most concentrated macrolide production cluster, benefiting from an integrated supply chain for erythromycin A starting material, specialized fermentation and chemical transformation expertise, and established environmental treatment infrastructure for macrolide production waste streams.

Our Manufacturing Process & Facility Standards

Our clarithromycin production begins with pharmaceutical-grade erythromycin A (produced at our affiliated fermentation facility), which undergoes selective 6-O-methylation — the critical chemical transformation that converts erythromycin to clarithromycin while preserving the macrolide ring’s acid-labile glycosidic bonds. This regioselective methylation is followed by protection/deprotection sequences, purification by selective crystallization, and final polymorphic form control. Production takes place in a 22,000 square meter quality-certified complex with ISO 14644-1 Class 7 cleanroom environments for all post-synthesis processing. Our facility features 15,000-liter main reaction vessels with automated temperature and addition rate control, dedicated mother liquor recycling systems for solvent recovery, and advanced crystal engineering equipment for polymorph control. In-process controls include HPLC monitoring at every isolation step, water activity measurement during crystallization, XRPD polymorph checks on every batch, and automated visual inspection of final product. Batch consistency across our last 200 commercial batches shows assay RSD of 0.5%, demonstrating world-class process control.

Quality Standards & Multi-Pharmacopeial Compliance

Our clarithromycin API is manufactured to comply with all major global pharmacopeias: ChP 2020, USP-NF, EP 11.0, JP XVIII, and BP. Typical assay values are 97.0-102.0% (on an anhydrous basis, per pharmacopeial range). Key quality parameters include: related substances by HPLC (6,11-di-O-methylerythromycin A ≤0.8%, each other impurity ≤0.5%, total ≤3.0% per EP), polymorphic form confirmation as Form II by XRPD (the preferred form for oral solid dosage), particle size distribution optimized for formulation (D50: 10-30 μm available, with custom PSD available), water content (≤2.0% by Karl Fischer), heavy metals (≤10 ppm), sulfated ash (≤0.1%), and residual solvents per ICH Q3C. Microbiological potency testing confirms activity ≥900 μg/mg. Our QC laboratory runs 20+ HPLC systems with dedicated macrolide analytical methods validated per ICH Q2. Complete COA with full impurity profiles accompanies every shipment.

Regulatory Documentation & Registration Support

Our clarithromycin API holds one of the most extensive regulatory filing portfolios in our product range. Current documentation includes: NMPA drug registration certificate, US FDA Type II DMF referenced by multiple ANDA holders, European CEP granted by EDQM, Japanese DMF filed with PMDA, WHO prequalification, quality certificates from Chinese NMPA and international audit bodies, and FDA facility registration with successful inspection history. Additional country-specific DMFs are filed in Brazil (ANVISA), Mexico (COFEPRIS), South Korea (MFDS), and numerous other markets. Our regulatory affairs team provides full-service registration support including CTD documentation, variation filings, post-approval change management, and inspection coordination. We have hosted over 15 international regulatory inspections for clarithromycin production with consistently favorable outcomes, demonstrating our commitment to regulatory transparency and compliance excellence.

Packaging, Storage & Global Logistics

Clarithromycin API is packaged in pharmaceutical-grade double polyethylene bags within fiber drums or aluminum drums. Standard packaging sizes include 10 kg, 25 kg, and 50 kg per drum, with bulk packaging up to 100 kg available for high-volume customers. Storage conditions require controlled room temperature (below 30°C) in a dry environment, with validated shelf life of 36 months. Our logistics operation handles high-volume clarithromycin shipments daily to destinations worldwide. We frequently ship full container loads (FCL) in 20′ and 40′ containers for maximum freight economy. Transit times include: 25-35 days to European ports by sea, 14-18 days by China-Europe rail, 18-25 days to South American ports, and 3-7 days by air freight globally. We maintain bonded warehouse inventory in key logistics hubs including Rotterdam and Singapore for rapid regional delivery. Complete export documentation including WHO CPP certificates is prepared by our experienced logistics team.

Competitive Pricing & Supply Reliability

As one of China’s largest clarithromycin producers with vertically integrated erythromycin supply, our production economics are among the most competitive globally. Competitive pricing eliminates trading company margins and delivers 30-50% savings compared to non-Chinese sources. MOQ is 100 kg for new customers, with standard commercial orders from 500 kg. We offer annual supply contracts with quarterly fixed pricing, volume rebate programs for purchases above 10 metric tons annually, and consignment stock arrangements at customer-nominated warehouses. Our monthly production capacity exceeds 100 metric tons, ensuring no allocation constraints. We maintain strategic erythromycin A starting material inventory covering 4 months of clarithromycin production, plus finished API safety stock of 50+ metric tons for immediate availability. Long-term supply reliability is further secured through our investment in captive erythromycin fermentation capacity.

Product Specifications