Quick Facts
| CAS Number | 315-30-0 |
|---|---|
| Molecular Formula | C5H4N4O |
| Molecular Weight | 136.11 |
| Pharmacopoeia | USP, EP, BP |
| Packaging | 25 KG/DRUM |
Product Overview
Allopurinol was developed in the early 1960s by the team of Gertrude B. Elion and George H. Hitchings at Burroughs Wellcome, as part of their pioneering work on purine metabolism. Their research program aimed to design compounds that would interfere with nucleic acid synthesis in rapidly dividing cells — work that ultimately earned them the 1988 Nobel Prize. Allopurinol was originally conceived as a candidate to potentiate the antileukemic drug 6-mercaptopurine by inhibiting its metabolic degradation via xanthine oxidase. During clinical testing, Elion and her colleagues Roland Robins and Wayne Rundles observed that allopurinol itself dramatically lowered serum and urinary uric acid levels — pivoting the compound from a chemotherapy adjuvant to the first effective urate-lowering therapy for gout.
The molecule's mechanism is elegantly straightforward: allopurinol is a structural isomer of hypoxanthine (nitrogen moved from position 7 to position 8) and acts as a substrate and inhibitor of xanthine oxidase. Both allopurinol and its longer-acting active metabolite oxypurinol bind to the molybdenum cofactor in the enzyme's active site, blocking the conversion of hypoxanthine to xanthine and xanthine to uric acid. This dual inhibition — parent drug plus active metabolite — means serum urate is suppressed for approximately 18-24 hours after a single dose, making once-daily dosing effective for most patients.
Allopurinol is also the standard prophylactic agent for tumor lysis syndrome, where rapid cancer cell destruction releases massive amounts of purines that would otherwise be metabolized to uric acid. By pre-treating patients before chemotherapy, allopurinol prevents uric acid nephropathy — a potentially fatal complication — by allowing the more soluble precursors hypoxanthine and xanthine to be renally excreted instead.
The allopurinol API market continues to grow steadily, valued at several hundred million USD globally. The compound is included in the WHO Model List of Essential Medicines and is the most prescribed urate-lowering drug worldwide. China is a major API producer, alongside India. The 2018 CARES trial results for febuxostat — which showed higher cardiovascular mortality versus allopurinol — reinforced allopurinol's position as the unrivaled first-line therapy and sustained API demand. KingWish supplies GMP-certified allopurinol meeting USP, EP, and BP standards.
Quality Specifications
| Assay (HPLC, dried basis) | 98.0% - 102.0% (USP) |
|---|---|
| Hypoxanthine (synthetic precursor) | ≤ 0.1% |
| Related Impurities | 3-aminopyrazole-4-carboxamide hemisulfate ≤ 0.1% |
| Loss on Drying | ≤ 0.5% |
| Heavy Metals | ≤ 10 ppm |
| Residual Solvents | Compliant with ICH Q3C |
| GMP Status | Manufactured under ICH Q7 GMP conditions |
Applications
- Chronic gout management: Xanthine oxidase inhibitor reducing uric acid production. First-line urate-lowering therapy for chronic gout with tophi, dosed at 100-800 mg/day.
- Hyperuricemia treatment: Prevents uric acid nephropathy and recurrent urate stones. Used in chemotherapy-induced hyperuricemia prophylaxis.
- Tumor lysis syndrome prevention: Prophylactic use in hematologic malignancies to prevent uric acid crystallization during chemotherapy induction and tumor debulking.
- Recurrent uric acid kidney stones: Reduces stone formation by lowering urinary uric acid excretion and increasing the solubility of purine metabolites.
Sourcing Allopurinol: Key Checks
Documentation
Request CoA with HPLC purity data, hypoxanthine content, and residual solvent statement. Verify particle size distribution for solid oral dosage uniformity. For regulated markets, confirm DMF/CEP status before ordering.
Red Flags
Elevated hypoxanthine indicates incomplete synthesis. Pyrazole-related impurities from cyclization side reactions. Suppliers claiming pharmacopoeia compliance without providing impurity profile chromatograms.
Packaging & Logistics
Standard: 25 KG/DRUM with inner PE liner. Store at room temperature (15-25 degrees Celsius), protected from light. Standard lead time 4-8 weeks. Custom packaging and micronization available on request.
Market Context
Allopurinol API market growing with rising gout prevalence globally (~1-4% of adults). WHO Essential Medicine. CARES trial (2018) reinforced allopurinol over febuxostat as first-line therapy. China and India are dominant API producers.