TCS Industries Limited (China-sourced API supplier) supplies Clarithromycin — API CAS 81103-11-9 for pharmaceutical B2B procurement — COA, MSDS, and technical documentation available on request.
> Overview
| Product Name | Clarithromycin |
|---|---|
| Structural Formula |  |
| CAS Number | 81103-11-9 |
| Molecular Formula | C₃₈H₆₉NO₁₃ |
| Molecular Weight | 748.0 g/mol |
| InChIKey | AGOYDEPGAOXOCK-KCBOHYOISA-N |
| SMILES | Available on request where applicable |
| Appearance | White to off-white crystalline powder |
| Purity / Grade | By agreed specification and batch COA |
| Storage | Room temperature, protect from light |
Clarithromycin (CAS 81103-11-9) is a macrolide antibiotic with the formula C₃₈H₆₉NO₁₃ (MW 747.95). It is a semi-synthetic derivative of erythromycin with a 6-O-methyl substitution that improves acid stability and oral bioavailability. Clarithromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. It is used for respiratory tract infections, H. pylori eradication, and MAC prophylaxis.
TCS Industries Limited, a Hong Kong-based trading and sourcing company, supplies Clarithromycin API in pharmaceutical grade for global procurement programs.
> Applications
Respiratory infections and H. pylori eradication
Clarithromycin 250–500 mg twice daily is used for community-acquired pneumonia, acute bacterial sinusitis, pharyngitis, and acute exacerbation of chronic bronchitis. In triple therapy with a PPI and amoxicillin, it eradicates H. pylori. The 6-O-methyl group prevents the acid-catalyzed intramolecular cyclization that degrades erythromycin in gastric acid. Zuckerman et al. (Infect Dis Clin North Am, 2004, 18:621–649) reviewed the pharmacokinetics and clinical applications of clarithromycin with emphasis on its improved acid stability and tissue penetration compared to erythromycin.
MAC prophylaxis and atypical mycobacteria
Clarithromycin 500 mg twice daily is used for Mycobacterium avium complex (MAC) prophylaxis and treatment in immunocompromised patients (HIV/AIDS with CD4 <50). Extended-release formulation (Biaxin XL, 1000 mg once daily) provides once-daily dosing convenience.
> Sourcing & Supply
TCS Industries Limited supports development, qualification and commercial purchasing discussions for Clarithromycin with buyers in Australia, New Zealand, Canada and South Korea.
- Evaluation and commercial quantities: 1 kg samples for formulation development; 5 kg and 25 kg for production. Pharmaceutical (USP/Ph.Eur.) grade. Semi-synthetic (from erythromycin A). Immediate-release and extended-release grades. DMF reference letters available.
- Pallet quantities and production campaigns: repeat supply is coordinated against packaging, lead time, annual demand and destination-market import requirements.
> Quality & Documentation
Key specification parameters include assay (≥96.0%), related substances (6,11-di-O-methyl erythromycin A ≤3.0%), loss on drying, residue on ignition, heavy metals, residual solvents, and microbial limits. White to off-white crystalline powder. Practically insoluble in water, soluble in acetone. Bitter taste. Identity by HPLC and IR. Meets USP (Clarithromycin), Ph.Eur. (Clarithromycinum), and JP. COA and MSDS are standard.
> Packaging
Clarithromycin is a white to off-white crystalline powder. Standard packaging includes double PE-lined foil bags in fibre drums (1 kg, 5 kg, or 25 kg). Store at controlled room temperature (15–25 °C). Protect from moisture. Shelf life is typically 36 months. Labels and documents are checked before dispatch.
> Pricing & MOQ
Pricing is quoted by specification, packaging and destination. Common commercial discussions use 25 kg bag/drum formats, pallet quantities and production-campaign planning; smaller samples may be reviewed for qualified formulation teams.
> Regulatory & Compounding Context
Clarithromycin is monographed in USP, Ph.Eur. (Clarithromycinum), BP, and JP. FDA-approved in 1991 (Biaxin). Extended-release (Biaxin XL) approved in 2000. EMA-authorized. On the WHO Model List of Essential Medicines. Off-patent with multiple generic approvals. DMF support available.
> Alias Index
- INN: Clarithromycin
- CAS Number: 81103-11-9
- Formula: C₃₈H₆₉NO₁₃ (MW 747.95)
- Brand names: Biaxin, Biaxin XL, Klacid
- ATC code: J01FA09
- Related: Erythromycin (parent macrolide), Azithromycin
- Commercial request terms: clarithromycin API, Biaxin generic, macrolide antibiotic API, H. pylori triple therapy, TCS Industries Limited
> FAQ
How does Clarithromycin improve on Erythromycin?
The 6-O-methyl group prevents acid-catalyzed degradation in the stomach. This results in improved oral bioavailability (~55% vs. ~25%), more consistent absorption, less GI side effects, longer half-life (3–4 hours vs. 1–2 hours), and higher tissue concentrations. Clarithromycin also produces an active 14-OH metabolite that contributes to antibacterial activity against H. influenzae.
What documents are available for Clarithromycin orders?
COA and MSDS are standard for commercial discussions. COO, packing list, invoice and other import-support documents can be arranged according to order scope.
Do you supply Clarithromycin to Australia and Canada?
Yes. We support B2B buyers in Australia, New Zealand, Canada and South Korea, subject to route and document review.
Do you supply New Zealand and South Korea?
Yes. We review Australia, New Zealand, Canada and South Korea for project supply, import documents, packaging and logistics planning before quotation.
What is the role in H. pylori eradication?
Clarithromycin 500 mg twice daily in triple therapy (with PPI and amoxicillin for 14 days) achieves 70–85% H. pylori eradication. Clarithromycin resistance (23S rRNA mutations) is increasing globally and reduces eradication rates to <50%. Susceptibility testing or local resistance data should guide therapy selection. Bismuth quadruple therapy is preferred where clarithromycin resistance exceeds 15%.
What drug interactions are important?
Clarithromycin is a potent CYP3A4 and P-glycoprotein inhibitor. It increases levels of statins (rhabdomyolysis risk with simvastatin/lovastatin), colchicine (fatal toxicity reported), carbamazepine, cyclosporine, and many other drugs. It also prolongs the QT interval and should not be combined with other QT-prolonging agents.
Can you arrange samples before commercial purchasing?
Samples or evaluation quantities may be reviewed for qualified buyers after target specification, application and destination-market requirements are clarified.
How is Clarithromycin packaged for export?
Packaging is confirmed by quantity and material properties. Typical options include foil bags, HDPE containers, fibre drums, 25 kg bags or palletized export packaging.
Can buyer-defined specifications be reviewed?
Yes. Send the specification, methods, impurity limits and required documents. TCS can review feasibility before confirming quotation and lead time.
What payment terms are normally used?
Standard payment is 100% T/T before dispatch unless a different arrangement has been approved for an established commercial account.
What lead time should buyers expect?
Lead time depends on stock, batch size, document scope and destination. Available stock can move faster; made-to-order or pallet programs require longer planning.
Is a DMF available?
Yes. TCS sources clarithromycin from semi-synthetic manufacturers who maintain active DMFs with the FDA and ASMF/CEP with EMA. Off-patent with extensive generic competition. COA, stability data, and DMF reference letters provided.
Last reviewed: June 2026
Evaluation and research orders (≤10 kg) are shipped with COA, MSDS, and certificate of origin. Bulk commercial orders (>10 kg) qualify for volume pricing with a full technical documentation package available on request.
> Request a Quote
If your team already has a target application, estimated quantity, destination market, or documentation requirements, send those details so the commercial response can be prepared more efficiently.