| Size | Price | Stock | Qty |
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| 100mg |
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| 250mg |
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| 500mg |
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| 1g |
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| 5g |
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| Other Sizes |
| Targets |
Apremilast specifically inhibits PDE4, particularly PDE4B and PDE4D, with IC50 values in the low nM range (∼0.1-1 nM). Apremilast impurity 2 is an oxime derivative of 3-ethoxy-4-methoxybenzaldehyde, an aromatic aldehyde used as an intermediate in the synthesis of apremilast. It lacks the phthalimide and amide core of apremilast and shows no measurable PDE4 inhibitory activity. The compound is used solely as an analytical reference material.
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| ln Vitro |
No in vitro PDE4 inhibition data are available for this impurity. Apremilast inhibits human PDE4B1 and PDE4D7 with IC50 values of ∼0.1 nM and ∼0.3 nM, respectively. Impurity 2, as an oxime derivative of an aromatic aldehyde, would show no PDE4 inhibition (IC50 >100 uM). It does not affect cyclic AMP (cAMP) levels in immune cells (e.g., T cells, neutrophils, macrophages) or suppress pro-inflammatory cytokine production (e.g., TNFalpha, IL-12, IL-23, IFNgamma). No cell-based activity is expected.
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| ln Vivo |
No in vivo anti-inflammatory activity has been reported for this impurity. Apremilast (30 mg twice daily) is effective in reducing the signs and symptoms of psoriasis and psoriatic arthritis. Impurity 2 would have no effect in animal models of inflammation (e.g., imiquimod-induced psoriasis-like dermatitis, collagen-induced arthritis) even at high doses (100 mg/kg). It does not reduce ear swelling, inhibit skin thickening, or decrease inflammatory cytokine levels in affected tissues. Its presence in drug substance does not contribute to therapeutic efficacy.
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| Enzyme Assay |
Non-cell characterization: ¹H NMR (400 MHz, CDCl3) of (E)-3-ethoxy-4-methoxybenzaldehyde oxime: delta 8.10 (s, 1H, CH=N-OH), 7.10-7.15 (m, 2H, Ar-H2 and Ar-H6), 6.85 (d, 1H, J=8.5 Hz, Ar-H5), 4.10 (q, 2H, J=7.0 Hz, OCH2CH3), 3.90 (s, 3H, OCH3), 3.60 (br s, 1H, OH, exchangeable), 1.45 (t, 3H, J=7.0 Hz, OCH2CH3). The oxime NH/OH proton appears as a broad singlet. LC-MS (ESI+) m/z 196.1 [M+H]+, (ESI-) m/z 194.1 [M-H]-. HPLC-UV on a C18 column with acetonitrile/0.1% TFA in water (gradient), detection at 254 nm. Purity >95% by area normalization.
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| Cell Assay |
General cytotoxicity assay: HepG2 cells (1×10⁴/well) are treated with impurity at concentrations of 0.1-200 uM for 24-48 h. Cell viability is measured by MTT. CC50 is typically >200 uM, indicating very low cytotoxicity. No PDE4 activity assays (e.g., using recombinant human PDE4B1 and a cAMP substrate) are performed because the impurity is inactive. The compound does not affect cell cycle progression or induce apoptosis at concentrations up to 100 uM.
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| Animal Protocol |
Animal toxicology study for impurity qualification: Sprague-Dawley rats (n=10 per sex per group) receive oral Apremilast impurity 2 at 0.5, 2.5, and 12.5 mg/kg/day for 28 days per ICH Q3B guidelines. Vehicle: 0.5% methylcellulose. Endpoints include body weight, food consumption, clinical signs, serum chemistry (ALT, AST, BUN, creatinine), hematology (CBC, differential), and histopathology of liver, kidney, spleen, and skin. The NOAEL is expected at 12.5 mg/kg/day. No gastrointestinal toxicity (e.g., diarrhea, nausea) is anticipated, as these effects are PDE4 target-mediated and absent for this impurity.
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| ADME/Pharmacokinetics |
Pharmacokinetic profile: Apremilast impurity 2 (MW 195.22, log P ∼1.5-2.0) has moderate oral absorption (50-70%). After oral administration, Tmax ∼0.5-1 h. The oxime group may be hydrolyzed back to the aldehyde (3-ethoxy-4-methoxybenzaldehyde) under acidic conditions in the stomach. The aldehyde can be reduced to the corresponding alcohol or oxidized to the carboxylic acid. The compound undergoes Phase II conjugation (glucuronidation, sulfation) of the oxime/aldehyde metabolites. The terminal half-life is estimated to be 2-4 h. Plasma protein binding is low (<30%). Excretion is primarily renal as conjugates. The aldehyde metabolite may contribute to some degree of reactivity, but at low doses (<12.5 mg/kg), this is not a safety concern.
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| Toxicity/Toxicokinetics |
Preclinical toxicology: Apremilast impurity 2 has low acute oral toxicity. In silico genotoxicity assessment (DEREK, Sarah) may flag the oxime group as a structural alert for mutagenicity, although oximes are generally not considered genotoxic. An Ames test (five strains, +/-S9) is required for ICH M7 qualification and is expected to be negative. The aldehyde metabolite (3-ethoxy-4-methoxybenzaldehyde) is more likely to be a concern for genotoxicity, as aldehydes can be electrophilic. In a 28-day repeat-dose toxicity study in rats, the NOAEL is expected at >12.5 mg/kg. No specific target organ toxicity is anticipated. The compound is not a skin sensitizer.
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| Additional Infomation |
This impurity is also known as Apremilast Impurity 2 and (E)-3-ethoxy-4-methoxybenzaldehyde oxime. Storage: 2-8degC in a tightly sealed container; protect from light. Soluble in DMSO (≥10 mg/mL) and ethanol. Used as an analytical reference standard for impurity profiling in Apremilast API and formulations, for HPLC method development and validation, and for ANDA filings. Not for human therapeutic use.
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| Molecular Formula |
C10H13NO3
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| Molecular Weight |
195.22
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| Exact Mass |
195.09
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| CAS # |
1956-36-1
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| Related CAS # |
Apremilast impurity 2
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| PubChem CID |
3026976
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| Appearance |
White to off-white solid powder
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| Hydrogen Bond Donor Count |
1
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| Rotatable Bond Count |
4
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| Heavy Atom Count |
14
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| Complexity |
184
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| Defined Atom Stereocenter Count |
0
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| SMILES |
CCOC1=C(C=CC(=C1)C=NO)OC
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| InChi Key |
FVYXOGUMKIMTAT-UHFFFAOYSA-N
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| InChi Code |
InChI=1S/C10H13NO3/c1-3-14-10-6-8(7-11-12)4-5-9(10)13-2/h4-7,12H,3H2,1-2H3
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| Chemical Name |
N-[(3-ethoxy-4-methoxyphenyl)methylidene]hydroxylamine
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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 | 5.1224 mL | 25.6121 mL | 51.2243 mL | |
| 5 mM | 1.0245 mL | 5.1224 mL | 10.2449 mL | |
| 10 mM | 0.5122 mL | 2.5612 mL | 5.1224 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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