Zileuton / A-64077 CAS No. 111406-87-2

Product Description

Zileuton is an orally active racemic (R/S) 5-lipoxygenase (5-LO) inhibitor used for chronic prevention of asthma (not for acute asthma exacerbations). Its chemical name is 1-[1-(1-benzothiophen-2-yl)ethyl]-1-hydroxyurea, which blocks the conversion of arachidonic acid to leukotriene A₄ (LTA₄), thereby reducing downstream leukotrienes (LTB₄, LTC₄, LTD₄, LTE₄) that mediate bronchoconstriction, inflammation, and mucus production. Zileuton is available in tablet and extended-release formulations, is virtually insoluble in water, and requires close monitoring due to its hepatotoxicity (elevated liver enzymes). It also interacts with theophylline, warfarin, and propranolol via inhibition of CYP1A2/3A4.

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Product Use & Characteristics

Basic Chemical Information

• Molecular Formula (MF): C₁₁H₁₂N₂O₂S

• Molecular Weight (MW): 236.29 g/mol

• IUPAC Name: 1-[1-(1-benzothiophen-2-yl)ethyl]-1-hydroxyurea

• Chemical Class:

  • 1-benzothiophene derivative

  • Hydroxyurea (urea-based)

  • Racemic mixture (R and S enantiomers both active)

Physical & Pharmacological Properties

Property	Details
Mechanism of Action	Selective, reversible 5-lipoxygenase (5-LO) inhibitor → blocks conversion of arachidonic acid to leukotrienes (LTB₄, LTC₄, LTD₄, LTE₄)
Therapeutic Categories	Anti-asthmatic • Leukotriene antagonist • NSAID-like anti-inflammatory • Ferroptosis inhibitor
Absorption	Oral bioavailability ≈ 25–30 % (BCS Class II – low solubility, high permeability)
Tmax	~1.7 h (immediate-release)
Vd	~4.9 L kg⁻¹
Metabolism	Hepatic, mainly CYP1A2 & CYP3A4
Half-life	~2.5 h (adults); gender differences in rodents (↑ t½ in females)
Excretion	Urine (~95 % as glucuronide conjugates)

Uses / Clinical Applications

• Primary:

  • Chronic asthma prophylaxis in adults & children ≥12 y (not for acute attacks)

• Investigational / Emerging:

  • Cancer stem-cell (CSC) targeting in breast, CML, lung, colon, ovarian cancers (via ALOX5 inhibition)

  • Metastasis prevention (reduces circulating tumor cells when formulated in polymer micelles)

  • Anti-acne (topical)

Formulation & Delivery Approaches

Formulation	Purpose / Advantage
Immediate-release tablet	600 mg; withdrawn from US market
Extended-release tablet	600 mg BID (1200 mg day⁻¹)
Nanocrystalline formulation (NfZ)	↑ solubility & oral bioavailability
Polymer micelles (Pluronic F127)	Intravenous delivery for oncology; 25 nm, stable, lyophilizable
2D-graphene electrochemical sensor	Ultra-sensitive detection (LOD 0.03 µM) in urine

Toxicity & Safety Warnings

Category	Details
State/Federal Labeling (e.g., CA Prop 65)	May cause cancer, developmental toxicity, female reproductive toxicity
Clinical Adverse Effects

• Hepatotoxicity (↑ ALT/AST – monitor LFTs)

• Neuropsychiatric events (insomnia, behavioral changes)

• GI upset, headache, leukopenia | | Drug Interactions | ↑ levels of theophylline, warfarin, propranolol (CYP1A2 inhibition) | | Contraindications | Active liver disease, hypersensitivity to zileuton

Research & Analytical Methods

• HPLC-UV / PDA / MS – validated for plasma, urine, tissues (LOD down to 1.8 × 10⁻⁸ M)

• HPTLC – 200–1200 ng band⁻¹, Rf 0.51 ± 0.02

• UV-AUC (hydrotropic SLS) – 2–12 µg mL⁻¹ linearity

• Electrochemical (graphene-modified CPE) – 0.3–100 µM linear, 0.03 µM LOD

Miscellaneous Notes

• ChEBI ID: CHEBI:10114

• Synonyms: Zyflo®, A-64077

• Storage & Handling: Protect from moisture; store at controlled room temperature

Why us!

Qingdao Sigma Chemical Co., Ltd., established in January 2017 and headquartered in Qingdao, China, is a reliable chemical supplier. Specializing in pharmaceuticals, biochemical intermediates, and research chemicals, the company offers a diverse product portfolio, including peptides (e.g., Tirzepatide, Semaglutide), nootropics, veterinary products, and APIs, often marketed with ≥99% purity and COA certification. We provides R&D, custom synthesis, and contract manufacturing services at various scales, while claiming a global export presence across 100+ countries. With international warehouses in the USA, Europe, Australia, and Canada, Qingdao Sigma Chemical also facilitates drop-shipping and reshipments, positioning itself as a key supplier for laboratory and research applications.