| Size | Price | Stock | Qty |
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| 1mg |
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| Other Sizes |
| Targets |
Ethionamide targets the InhA enzyme (enoyl-ACP reductase) involved in mycolic acid biosynthesis, a critical component of the Mycobacterium tuberculosis cell wall. It functions as a prodrug that requires metabolic activation via oxidation by flavin monooxygenase (specifically EthA monooxygenase) within the bacterial cell. The activated form inhibits InhA, disrupting mycolic acid synthesis and leading to bacterial cell death.
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| ln Vitro |
Drug compounds have included stable heavy isotopes of carbon, hydrogen, and other elements, mostly as tracers for quantification throughout the drug development process. Due to its potential to alter the pharmacokinetic and metabolic characteristics of medications, deuteration has drawn attention[1].
In vitro, ethionamide shows potent antimycobacterial activity against Mycobacterium tuberculosis with minimum inhibitory concentrations (MICs) ranging from 0.3-1.25 ug/mL. It is activated via oxidation by flavin monooxygenase and specifically inhibits the InhA enzyme. Ethionamide-d3 is not typically studied for independent bioactivity as it is used as an analytical standard, but it retains the same antimicrobial activity as unlabeled ethionamide due to minimal isotope effect on binding. |
| ln Vivo |
In vivo, ethionamide is effective against susceptible and some drug-resistant strains of M. tuberculosis in animal models of tuberculosis. The compound distributes well into tissues including lung tissue where mycobacteria reside. Ethionamide-d3 serves as a tracer to study the pharmacokinetic behavior and tissue distribution of ethionamide following oral or intravenous administration in preclinical species, enabling accurate quantification of drug concentrations by mass spectrometry.
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| Enzyme Assay |
For receptor-binding or enzyme inhibition assays of ethionamide-d3, the same protocols apply as for unlabeled ethionamide. Incubate purified InhA enzyme (0.1-1 ug) with varying concentrations of ethionamide-d3 (0.1-100 uM) in reaction buffer (100 mM HEPES, 100 mM KCl, 1 mM DTT, pH 7.5) for 10-30 minutes at 25degC. Add substrate (2-trans-enoyl-ACP or crotonoyl-CoA) and NADH (100 uM). Measure NADH consumption by absorbance at 340 nm over 5-15 minutes. IC50 values typically in the 0.1-1 uM range.
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| Cell Assay |
For M. tuberculosis culture assays (BACTEC or broth microdilution), grow M. tuberculosis H37Rv in Middlebrook 7H9 broth supplemented with 10% OADC enrichment at 37degC. Prepare 2-fold serial dilutions of ethionamide-d3 (0.08-10 ug/mL) in 96-well plates. Add bacterial inoculum (approximately 5 × 10^5 CFU/mL). Incubate for 5-7 days. Add resazurin (12.5 ug/mL) and incubate for additional 4-24 hours; visual color change from blue to pink indicates growth. Determine MIC as the lowest concentration preventing color change. For isotope tracer studies, add ethionamide-d3 (1-10 uM) to bacterial cultures and measure intracellular concentrations by LC-MS.
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| Animal Protocol |
For pharmacokinetic studies, administer ethionamide-d3 to mice, rats, or dogs by oral gavage (20-100 mg/kg) or intravenous injection (5-20 mg/kg). Collect blood at predetermined time points (0, 0.5, 1, 2, 4, 6, 8, 12, 24 hours post-dose). Harvest plasma and various tissues (lung, liver, kidney, spleen) at selected time points. Extract with acetonitrile or solid-phase extraction and analyze by LC-MS/MS using the d3 label for internal standardization. Calculate PK parameters: Cmax, Tmax, AUC, t1/2, clearance, volume of distribution, and oral bioavailability.
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| ADME/Pharmacokinetics |
Ethionamide-d3 demonstrates similar pharmacokinetic properties to unlabeled ethionamide. Ethionamide is rapidly absorbed after oral administration, with peak plasma concentrations reached within 1-2 hours. It has a terminal elimination half-life of approximately 2-4 hours in humans and rodents. Oral bioavailability is high (>80%). The compound is extensively metabolized in the liver, primarily by flavin-containing monooxygenases and cytochrome P450 enzymes, with metabolites including the active sulfoxide form and inactive conjugates excreted in urine.
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| Toxicity/Toxicokinetics |
Deuterium substitution has the potential to alter pharmacokinetic properties due to kinetic isotope effects, potentially reducing metabolic clearance and extending half-life. The toxicity profile of ethionamide-d3 is expected to be similar to that of unlabeled ethionamide. Ethionamide can cause dose-dependent adverse effects including gastrointestinal disturbances (nausea, vomiting, diarrhea), hepatotoxicity, hypothyroidism, and neurologic symptoms (headache, dizziness, peripheral neuropathy). Chronic use requires monitoring of liver function and thyroid hormones. The compound is not for human use as a research standard.
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| References |
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| Additional Infomation |
Ethionamide-d3 is a stable isotope-labeled compound used as an internal standard in bioanalytical method development for quantification of ethionamide in biological matrices. Ethionamide remains an important drug for MDR-TB treatment, often used in combination with other second-line drugs including kanamycin, capreomycin, and fluoroquinolones. The drug is activated by the bacterial EthA monooxygenase; mutations in the ethA gene are a common mechanism of ethionamide resistance. Store ethionamide-d3 desiccated at -20degC protected from light.
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| Molecular Formula |
C8H7D3N2S
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|---|---|
| Molecular Weight |
169.26
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| Related CAS # |
Ethionamide;536-33-4
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| Appearance |
Typically exists as solid at room temperature
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples
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| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 5.9081 mL | 29.5404 mL | 59.0807 mL | |
| 5 mM | 1.1816 mL | 5.9081 mL | 11.8161 mL | |
| 10 mM | 0.5908 mL | 2.9540 mL | 5.9081 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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