| Size | Price | Stock | Qty |
|---|---|---|---|
| 1mg |
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| Other Sizes |
| Targets |
The labeled compound is chemically identical to unlabeled sulfadiazine but is non-radioactive and used as an internal standard. Unlabeled sulfadiazine targets bacterial and parasitic dihydropteroate synthase (DHPS), a key enzyme in the folate synthesis pathway. Sulfadiazine is a competitive inhibitor of para-aminobenzoic acid (PABA), preventing the formation of dihydropteroic acid and thus inhibiting bacterial DNA and RNA synthesis. It is bacteriostatic. The 13C-labeled version has no biological activity at the trace concentrations used (typically ng/mL). Its structure is identical except for isotopic enrichment, so it behaves identically in extraction, chromatography, and ionization, making it an ideal internal standard.
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| ln Vitro |
Not applicable as an internal standard. In vitro, unlabeled sulfadiazine has minimum inhibitory concentrations (MICs) of 1-32 ug/mL against Streptococcus pyogenes, Escherichia coli, and other susceptible bacteria. Against Toxoplasma gondii (in vitro, in human foreskin fibroblasts), sulfadiazine alone has an IC50 of 5 ug/mL, but when combined with pyrimethamine, the IC50 is reduced to 0.5 ug/mL. The labeled compound is not used for activity testing. Its utility is demonstrated by method validation: linearity (r2 > 0.999), accuracy (95-105% recovery), precision (CV < 5%), and matrix effect (ion suppression <10%).
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| ln Vivo |
Not applicable. In vivo, unlabeled sulfadiazine is used to treat nocardiosis, urinary tract infections, and toxoplasmosis. It distributes widely, crosses the blood-brain barrier, and reaches therapeutic concentrations in CSF (30-50% of plasma). The labeled version is not used therapeutically. However, in pharmacokinetic studies, sulfadiazine-13C6 is co-administered as a tracer to accurately measure the parent drug concentration in the presence of metabolites, but this is done in research settings only, not in patients.
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| Enzyme Assay |
Standard LC-MS/MS method development: Prepare sulfadiazine-13C6 as a 1 mg/mL stock in DMSO, then dilute to working concentration (e.g., 1 ug/mL) in acetonitrile. For calibration, spike blank plasma (100 uL) with unlabeled sulfadiazine at 0.5-5000 ng/mL, then add 10 uL of internal standard solution (final concentration 100 ng/mL). Add 300 uL of acetonitrile, vortex, centrifuge at 14,000 rpm for 10 min. Inject 5 uL of supernatant onto a C18 column (2.1 × 50 mm, 1.7 um) with mobile phase: 0.1% formic acid in water / acetonitrile (gradient from 5% to 95% acetonitrile over 3 min). MS/MS in positive mode: unlabeled sulfadiazine m/z 251 → 156 (quantifier) and 251 → 108 (qualifier); labeled internal standard m/z 257 → 162 (or 156+6). Linearity, LLOQ, and recovery are evaluated.
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| Cell Assay |
Not applicable for pharmacology. For metabolic stability experiments, sulfadiazine-13C6 is used as an internal standard in hepatocyte incubation studies. Human hepatocytes (0.5 × 10^6 cells/mL) are incubated with 10 uM unlabeled sulfadiazine for 0, 15, 30, 60, 90, and 120 min. At each time point, the reaction is stopped with acetonitrile containing 100 ng/mL sulfadiazine-13C6. After centrifugation, the supernatant is analyzed by LC-MS/MS to quantify remaining parent drug. The half-life is calculated. The internal standard corrects for variations in sample preparation and instrument response.
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| Animal Protocol |
Sulfadiazine-13C6 is not used in animal studies as a test article; it is used as an analytical reagent to measure sulfadiazine concentrations in samples from animal pharmacokinetic studies. For example, in a rat PK study: Male Sprague-Dawley rats (n=6) receive a single oral dose of unlabeled sulfadiazine (50 mg/kg). Blood is collected at 0, 0.25, 0.5, 1, 2, 4, 8, 12, 24 h. Plasma (50 uL) is spiked with 10 uL of sulfadiazine-13C6 (1 ug/mL) and processed as above. The concentration of unlabeled sulfadiazine is calculated from the peak area ratio (sulfadiazine / internal standard) using the calibration curve. PK parameters (Cmax, Tmax, AUC, t1/2) are then computed. The internal standard improves accuracy and precision.
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| ADME/Pharmacokinetics |
The labeled compound has identical PK to unlabeled sulfadiazine but is administered only at trace levels (ug/kg) if used as an IV tracer. Unlabeled sulfadiazine PK: in humans, oral bioavailability is 70-100%; plasma protein binding = 40-60%; half-life = 7-12 h (normal renal function); metabolism primarily via acetylation (N-acetylsulfadiazine, inactive); excretion: 70-90% unchanged in urine. In rats, half-life is 3-5 h, oral bioavailability 80%. The labeled compound is not separately studied for PK.
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| Toxicity/Toxicokinetics |
The labeled compound is non-toxic at the trace amounts used (e.g., 10-100 ng per injection). Unlabeled sulfadiazine has known toxicities: crystalluria (due to low solubility in acidic urine), skin rash (including Stevens-Johnson syndrome), photosensitivity, blood dyscrasias (agranulocytosis, thrombocytopenia), and GI disturbances. The labeled standard should be handled with the same precautions as the parent drug: use in a fume hood, wear gloves and lab coat. Avoid inhalation of powder. For the labeled compound, no additional toxicity data are needed because it is a stable isotope variant.
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| References | |
| Additional Infomation |
Sulfadiazine-13C6 is a research-grade internal standard, not for human therapeutic use. It is essential for regulatory bioanalysis of sulfadiazine in food safety (milk, meat, honey) and clinical therapeutic drug monitoring. It complies with FDA and EMA guidelines for bioanalytical method validation. No clinical trials are performed on the labeled compound. It is commercially available from chemical suppliers. The compound is often used in combination with other isotope-labeled sulfonamides (e.g., sulfamethoxazole-13C6) for multi-analyte panels. Because the labeling is stable (no isotopic exchange), it can be stored for years at -20degC. It is not intended for animal dosing except as an internal standard spike. Note: The compound may also be labeled as “Sulfadiazine-13C6” or “Sulfadiazine (phenyl-13C6)”.
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| Molecular Formula |
13C4C6H10N4O2S
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|---|---|
| Molecular Weight |
256.233
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| Exact Mass |
256.073
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| CAS # |
1189426-16-1
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| Related CAS # |
Sulfadiazine;68-35-9;Sulfadiazine-d4;1020719-78-1
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| PubChem CID |
46782960
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| Appearance |
Typically exists as solid at room temperature
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| Melting Point |
255-256°C (dec.)
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| LogP |
2.594
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| Hydrogen Bond Donor Count |
2
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| Hydrogen Bond Acceptor Count |
6
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| Rotatable Bond Count |
3
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| Heavy Atom Count |
17
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| Complexity |
327
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| Defined Atom Stereocenter Count |
0
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| SMILES |
N[13C]1[13CH]=[13CH][13C](S(NC2N=CC=CN=2)(=O)=O)=[13CH][13CH]=1
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| InChi Key |
SEEPANYCNGTZFQ-AHBHZWPESA-N
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| InChi Code |
InChI=1S/C10H10N4O2S/c11-8-2-4-9(5-3-8)17(15,16)14-10-12-6-1-7-13-10/h1-7H,11H2,(H,12,13,14)/i2+1,3+1,4+1,5+1,8+1,9+1
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| Chemical Name |
4-amino-N-pyrimidin-2-yl(1,2,3,4,5,6-13C6)cyclohexa-1,3,5-triene-1-sulfonamide
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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 | 3.9027 mL | 19.5137 mL | 39.0274 mL | |
| 5 mM | 0.7805 mL | 3.9027 mL | 7.8055 mL | |
| 10 mM | 0.3903 mL | 1.9514 mL | 3.9027 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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