Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
The information in this record pertains to the use of urea C13 as a diagnostic reagent. Since carbon-13 is not radioactive, no special precautions are required for breastfeeding women.
◉ Effects on Breastfed Infants
No relevant published information was found as of the revision date.
◉ Effects on Lactation and Breast Milk
No relevant published information was found as of the revision date.

Urea C-13 is a compound modified with 13C, in which the carbon exists as an isotope of 13C. It is a 13C-modified compound and also a single-carbon compound. Urea 13C is a urea molecule labeled with the non-radioactive element carbon-13. It is currently used in the urea breath test (UBT) and as a rapid diagnostic reagent (marketed under the brand name Pranactin-Citric) for detecting Helicobacter pylori infection. Helicobacter pylori is a common gastric bacterium associated with various upper gastrointestinal diseases, such as gastritis, gastric ulcers and peptic ulcers, gastric cancer, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. UBT is suitable for confirming Helicobacter pylori infection and monitoring its eradication after treatment. Radiolabeled urea exists in two forms: 13C and 14C. Both forms can be used in the urea breath test, but some people may prefer to use urea-13C because it is not radioactive, while urea-14C may be more suitable for pregnant women and children. The urea breath test is based on the ability of Helicobacter pylori urease to break down urea into ammonia and carbon dioxide. Since urease is not present in mammalian cells, the presence of urease (and urea breakdown products) in the stomach indicates the presence of Helicobacter pylori. To detect Helicobacter pylori, the patient swallows urea labeled with urea-13C. If urease from Helicobacter pylori is present in the stomach, the urea breaks down into carbon dioxide and ammonia at the junction of the gastric epithelium and the gastric lumen. The urea-13C is absorbed into the bloodstream and exhaled. A sample of the exhaled gas can then be collected, and the presence of radioactivity can be measured. Urea C-13 is a diagnostic reagent for Helicobacter pylori. Urea C-13 is a radiolabeled urea molecule used to diagnose gastric ulcers caused by Helicobacter pylori. In the presence of Helicobacter pylori, urea C-13 is metabolized by urease, producing ammonia and radioactive carbon dioxide at the junction of the gastric epithelium and the gastric lumen. The radioactive carbon dioxide is absorbed into the bloodstream and detected in exhaled breath. See also: citric acid; urea C-13 (component).

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Drug Indication
Urea-13C is suitable for the qualitative detection of Helicobacter pylori-associated urease in the human stomach and can aid in the initial diagnosis and post-treatment monitoring of Helicobacter pylori infection in adult patients. This test can be used to monitor treatment effectiveness at least four weeks (4 weeks) after the completion of treatment. For this purpose, the system uses an infrared spectrophotometer to measure the ratio of 13CO2 to 12CO2 in a breath sample.
FDA Label

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Mechanism of Action
The urea breath test is based on the ability of Helicobacter pylori urease to break down urea into ammonia and carbon dioxide. Since urease is absent in mammalian cells, the presence of urease (and its breakdown products) in the stomach indicates the presence of Helicobacter pylori. To detect Helicobacter pylori, the patient swallows urea labeled with ¹³C. If urease from Helicobacter pylori is present in the stomach, the urea breaks down at the interface between the gastric epithelium and the gastric lumen, producing CO₂ and NH₃. ¹³C₂ is absorbed into the bloodstream and exhaled. A sample of the exhaled gas can then be collected and its radioactivity measured.

13CH4N2O

61.05

61.035

58069-82-2

636363

White to off-white solid powder

1.212g/cm3

132-135ºC(lit.)

1.468

0.424

2

1

0

4

29

0

N[13C](N)=O

XSQUKJJJFZCRTK-OUBTZVSYSA-N

InChI=1S/CH4N2O/c2-1(3)4/h(H4,2,3,4)/i1+1

diamino(113C)methanone

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

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

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.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*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).

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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)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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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).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)