Quick Facts
| CAS Number | 70288-86-7 |
|---|---|
| Molecular Formula | B1a (C48H74O14), B1b (C47H72O14) |
| Molecular Weight | 875.1 |
| Pharmacopoeia | EP/USP/IN HOUSE |
| Packaging | 25 KG/DRUM |
Product Story
Ivermectin was discovered in the mid-1970s through a landmark international scientific collaboration. In 1973, Japanese microbiologist Satoshi Omura isolated a novel actinobacterium, Streptomyces avermitilis, from a soil sample collected near a golf course in Ito, Japan. Omura sent the culture to Merck Research Laboratories in the United States, where parasitologist William C. Campbell's team discovered that fermentation broths of the organism contained potent anti-parasitic macrocyclic lactones — named avermectins. Through chemical reduction, the most active derivative, 22,23-dihydroavermectin B1 (ivermectin), was developed and launched in 1981.
Ivermectin acts by selectively and irreversibly binding to glutamate-gated chloride ion channels (GluCls) in invertebrate nerve and muscle cells. This binding increases chloride ion permeability, causing hyperpolarization of the cell membrane, paralysis, and death of the parasite. Mammals lack GluCls in their peripheral nervous system (the channels are confined to the CNS, protected by the blood-brain barrier), which accounts for ivermectin's remarkable safety margin in livestock — typically >100-fold between therapeutic and toxic doses.
Ivermectin's unique advantage is its dual action as both an endectocide (killing internal nematodes) and an ectoparasiticide (killing external mites, lice, ticks). A single administration provides broad-spectrum parasite control that previously required multiple products. The discovery of avermectins (lead compound of ivermectin) earned Omura and Campbell half of the 2015 Nobel Prize in Physiology or Medicine (shared with Tu Youyou for artemisinin), with the Nobel Committee declaring that these drugs "have revolutionized the treatment of some of the most devastating parasitic diseases." Ivermectin transformed veterinary medicine — it remains the most widely used veterinary antiparasitic agent globally, with billions of doses administered across cattle, sheep, swine, horses, poultry, and companion animals.
As of mid-2026, the global veterinary ivermectin API market is driven by expanding livestock production in Asia, Latin America, and Africa, where parasite control directly impacts meat, milk, and fiber yields. Growing resistance in gastrointestinal nematodes, particularly Haemonchus contortus in small ruminants, is pushing demand toward combination products and higher-purity API. China is the dominant producer of ivermectin API, with manufacturing concentrated in Shandong and Hebei provinces. Quality differentiation — between GMP-grade and agricultural-grade material — is widening as regulatory agencies tighten antiparasitic residue monitoring in food-producing animals.
Quality Specifications
| Purity (HPLC) | ≥ 95.0% B1a component, B1a + B1b ≥ 97.0% (anhydrous basis), per EP/USP |
|---|---|
| Component Ratio | B1a ≥ 90.0% (EP); B1b ≤ 5.0% (critical quality attribute for bioactivity) |
| Related Substances | Any individual unspecified impurity ≤ 1.0%; total impurities ≤ 3.0% (EP) |
| Residual Solvents | Compliant with ICH Q3C; ethanol ≤ 5,000 ppm |
| Heavy Metals | ≤ 20 ppm |
| GMP Status | Manufactured under ICH Q7 GMP conditions |
| Key Tests | Loss on drying ≤ 1.0%; specific optical rotation -20° to -17°; identity confirmed by IR spectrum |
Veterinary Applications
Injectable & Pour-On (Cattle)
1% injectable and 0.5% pour-on formulations. Controls GI roundworms, lungworms, cattle grubs, lice, and mange mites. Standard dose: 0.2 mg/kg SC injection or 0.5 mg/kg pour-on.
Oral Drench & Paste (Sheep, Horses)
Oral drench for sheep (0.08%) at 0.2 mg/kg. Oral paste for horses (1.87%) for strongyles, ascarids, pinworms, and stomach bots. Extended protection from a single administration.
Therapeutic Areas
- Cattle: Pour-on and injectable formulations for GI roundworms, lungworms, grubs, lice, and mites
- Sheep & Goats: Oral deworming for Haemonchus, Ostertagia, Trichostrongylus, and nasal bots
- Swine: Injectable and in-feed formulations for Ascaris, Hyostrongylus, and sarcoptic mange
- Horses: Oral paste for strongyles, ascarids, pinworms, and stomach bots
- Poultry: Mite and lice control in commercial layer and breeder operations
- Companion Animals: Heartworm prevention in dogs (oral tablets, monthly dosing)
Sourcing Ivermectin API: Key Checks
Documentation
Request CoA with HPLC assay showing B1a/B1b component ratio, impurity profile, and residual solvent statement. Verify GMP certificate validity. For regulated markets, confirm VMF/DMF filing status and pharmacopoeia compliance (EP or USP).
Red Flags
Low B1a content (below EP limit of 90.0%), elevated degradation products indicating improper fermentation control or poor storage, pricing far below market range (suggesting non-GMP or agricultural-grade material), and refusal to share batch-specific component ratio data.
Packaging & Logistics
Standard: 25 KG/DRUM, light-resistant packaging recommended. Ivermectin is photolabile — verify aluminum foil-lined drums or opaque containers. Store at controlled room temperature (15-25 °C). Standard lead time 4-8 weeks.
Market Context
Global ivermectin API market growing at 4-6% CAGR, driven by livestock expansion in Asia-Pacific and Africa. Rising anthelmintic resistance is shifting demand toward combination products and GMP-pure API. China dominates global production (>80% of supply). Market report