| Size | Price | Stock | Qty |
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| 1mg |
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| 5mg |
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| 10mg |
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| Other Sizes |
| Targets |
Daunorubicins/Doxorubicins
The active payload is doxorubicin, which targets topoisomerase II, leading to DNA intercalation, inhibition of DNA replication and transcription, and induction of apoptosis. The VC linker is specifically cleaved by cathepsin B, an enzyme that is overexpressed in the lysosomes of many cancer cells, enabling targeted drug release. |
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| ln Vitro |
The doxorubicin payload intercalates into DNA and inhibits topoisomerase II, resulting in DNA double‑strand breaks, G2/M cell cycle arrest and caspase‑dependent apoptosis. The PEG4 spacer enhances hydrophilicity and solubility, reducing aggregation. The non‑cleaved conjugate is inactive due to the PAB spacer blocking doxorubicin's activity.
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| ln Vivo |
In animal xenograft models, anti‑tumour antibodies conjugated to Azide‑PEG4‑VC‑PAB‑Doxorubicin via click chemistry release doxorubicin specifically within tumour cells following cathepsin B cleavage. This results in targeted tumour regression with significantly reduced systemic toxicity (e.g., less cardiotoxicity and myelosuppression) compared to free doxorubicin or non‑cleavable conjugates.
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| Enzyme Assay |
A general cathepsin B cleavage assay: Incubate Azide‑PEG4‑VC‑PAB‑Doxorubicin (10 uM) with recombinant human cathepsin B (100 ng/mL) in cleavage buffer (50 mM sodium acetate pH 5.0, 2 mM DTT, 1 mM EDTA) at 37degC for 4‑24 h. The reaction is stopped by adding 0.1% TFA. Release of free doxorubicin is quantified by reverse‑phase HPLC or LC‑MS. Controls without cathepsin B determine background cleavage.
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| Cell Assay |
A general ADC cellular uptake and cytotoxicity assay: Target antigen‑expressing cancer cells (e.g., HER2‑positive SK‑BR‑3, CD33‑positive HL‑60) are seeded in 96‑well plates (5×103 cells/well). The azide‑functionalised ADC construct is conjugated to a dibenzocyclooctyne (DBCO)‑modified antibody via SPAAC click chemistry. Conjugates are added at 0.01‑100 nM (doxorubicin equivalent) and incubated for 72‑96 h. Cell viability is assessed by CellTiter‑Glo. Lysosomal co‑localisation and doxorubicin nuclear release can be visualised by confocal microscopy (doxorubicin autofluorescence).
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| Animal Protocol |
A general in vivo ADC efficacy protocol: Female NSG or BALB/c nude mice (n=8/group) are implanted subcutaneously with 5×10⁶ target antigen‑positive cancer cells. When tumours reach ~150 mm3, mice receive a single intravenous injection of DBCO‑antibody followed 24 h later by Azide‑PEG4‑VC‑PAB‑Doxorubicin (10 mg/kg, doxorubicin equivalent), or a pre‑formed ADC via SPAAC click conjugation. Tumour volumes are measured every 3‑4 days for 4‑6 weeks. Body weight and blood counts are monitored weekly. At endpoint, tumours are collected for histology (TUNEL, Ki‑67) and doxorubicin concentration by LC‑MS.
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| ADME/Pharmacokinetics |
Azide‑PEG4‑VC‑PAB‑Doxorubicin itself is not intended for administration as a free drug; its pharmacokinetics are determined by the antibody conjugate. The PEG4 spacer reduces aggregation and prolongs circulation half‑life. The VC linker is stable in plasma (t1/2 > 48 h) but rapidly cleaved in lysosomal compartments (t1/2 ~2‑4 h). The azide group does not affect PK but enables bioorthogonal conjugation.
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| Toxicity/Toxicokinetics |
Free doxorubicin causes dose‑limiting cardiotoxicity and myelosuppression. However, when delivered via the cleavable ADC construct, the active payload is released primarily in tumour cells, significantly reducing systemic exposure and toxicity. The VC linker and PEG4 spacer are biocompatible and non‑toxic. No additional toxicity is introduced by the azide or PAB groups at therapeutic doses.
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| References | |
| Additional Infomation |
This construct is a research‑grade ADC intermediate, not an approved drug. It enables site‑specific conjugation of doxorubicin to antibodies or targeting ligands via strain‑promoted alkyne‑azide cycloaddition (SPAAC) or copper‑catalysed click chemistry, providing a homogeneous and stable ADC for in vitro and in vivo evaluation. The cleavable VC linker allows selective drug release in the tumour microenvironment, potentially improving the therapeutic index of doxorubicin.
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| Molecular Formula |
C57H75N9O21
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| Molecular Weight |
1222.25
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| Appearance |
Orange to red solid powder
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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) |
DMSO :~100 mg/mL (~81.82 mM)
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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 | 0.8182 mL | 4.0908 mL | 8.1816 mL | |
| 5 mM | 0.1636 mL | 0.8182 mL | 1.6363 mL | |
| 10 mM | 0.0818 mL | 0.4091 mL | 0.8182 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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