Xanthine-13C,15N2 itself does not have a defined biological target as a drug; rather, it is a tracer compound used in research. However, the parent compound xanthine is known to exhibit adenosine receptor antagonist activities. Xanthine and its derivatives (such as caffeine and theobromine) act as non-selective antagonists at adenosine A1 and A2A receptors, producing mild stimulatory effects on the central nervous system. As an isotopically labeled analog, this compound is used to trace the metabolic fate of xanthine without altering its intrinsic biological activity.

Drug compounds have included stable heavy isotopes of carbon, hydrogen, and other elements, mostly as quantitative tracers while the drugs were being developed. Because deuteration may affect a drug's pharmacokinetics and metabolic properties, it is a cause for concern [75].

---

Xanthine-13C,15N2 is not evaluated for in vitro biological activity as a drug; it is a stable isotope-labeled research compound used as an internal standard or tracer. The parent compound xanthine exhibits mild stimulatory effects on the central nervous system through adenosine receptor antagonism. As an intermediate in the purine degradation pathway, xanthine is metabolized by xanthine oxidase to uric acid. The labeled version allows researchers to quantify and track these metabolic transformations without interfering with the underlying biological processes.

Xanthine-13C,15N2 is not administered as a therapeutic agent and does not have intrinsic in vivo pharmacological activity. It is used as a metabolic tracer in animal studies to investigate purine metabolism, drug metabolism, and pharmacokinetics. When administered to research animals, the labeled compound can be detected in biological samples (blood, urine, tissues) using mass spectrometry, enabling precise quantification of xanthine levels and its metabolic conversion to uric acid and other metabolites.

There are no specific in vitro enzyme/receptor binding assays for Xanthine-13C,15N2 as it is a tracer compound. However, the parent compound xanthine can be studied in adenosine receptor binding assays using radiolabeled ligands such as 3H-CHA or 3H-ZM241385. Membrane preparations from cells expressing adenosine receptors are incubated with the radioligand and varying concentrations of unlabeled xanthine, and bound radioactivity is measured by scintillation counting. For xanthine oxidase activity assays, xanthine is incubated with the enzyme and the production of uric acid is monitored spectrophotometrically at 290 nm.

There are no specific in vitro cellular assays for Xanthine-13C,15N2 as a pharmacologically active compound. As a tracer, it can be added to cell culture media (typically at 1-100 μM) and incubated with various cell lines (e.g., hepatocytes, cancer cells) for 1-24 hours. Cellular uptake and metabolism are analyzed by LC-MS/MS to quantify the labeled compound and its metabolites. Cell viability can be assessed using MTT assays to ensure the labeled compound does not affect cell health. The compound is generally considered biologically inert as a tracer.

There are no specific in vivo animal studies for Xanthine-13C,15N2 as a pharmacologically active compound. As a metabolic tracer, it can be administered to rodents orally or intravenously at doses of 1-10 mg/kg. Blood samples are collected at various time points (0.083, 0.25, 0.5, 1, 2, 4, 8, 24 hours post-dose), and plasma is analyzed by LC-MS/MS to determine the pharmacokinetic profile of labeled xanthine. Tissues (liver, kidney, brain) may be harvested for metabolic profiling.

Metabolism / Metabolites
Xanthine is readily converted into uric acid. Xanthine oxidase can convert xanthine and hypoxanthine into uric acid, while xanthine and hypoxanthine are generated from other purines. In humans and higher primates, uric acid is the final oxidation (decomposition) product of purine metabolism and is excreted in urine.

---

Pharmacokinetic properties of Xanthine-13C,15N2 are not studied as a drug; however, the labeled compound can be used to study the pharmacokinetics of xanthine itself. Xanthine is rapidly absorbed and distributed throughout the body. It is primarily metabolized by xanthine oxidase to uric acid in the liver and intestines. The elimination half-life of xanthine in humans is approximately 1-2 hours. The compound is excreted in urine as uric acid and other metabolites. The labeled version allows for precise tracking of these processes using mass spectrometry.

Toxicity Summary
Xanthine is a poorly soluble compound. Therefore, excessively high concentrations of xanthine in serum can lead to the formation of kidney stones (xanthine nephropathy), and in the long term, may result in kidney failure.

---

The toxicity profile of Xanthine-13C,15N2 is not reported, as it is a stable isotope-labeled research compound used in trace amounts. The parent compound xanthine is generally considered safe at physiological concentrations. At very high concentrations, xanthine can cause adverse effects related to uric acid overproduction, such as hyperuricemia and gout. The compound is for research use only and not for human therapeutic use. No specific genotoxicity or carcinogenicity data are reported.

[1]. Impact of Deuterium Substitution on the Pharmacokinetics of Pharmaceuticals. Ann Pharmacother. 2019;53(2):211-244.

[2]. Biosensing methods for xanthine determination: a review. Enzyme Microb Technol. 2014;57:55-62.

[3]. Central Nervous SystemStimulants.

9H-xanthine is an oxopurine with oxo groups at positions 2 and 6 of the purine ring and protonation at positions N-9. It is a metabolite of Saccharomyces cerevisiae and a tautomer of 7H-xanthine. Xanthine is a purine base found in most human tissues and fluids, some plants, and some urinary tract stones. It is an intermediate in the degradation of adenosine monophosphate to uric acid, produced by the oxidation of hypoxanthine. Methylated xanthine compounds, such as caffeine, theobromine, and theophylline and their derivatives, are used medically for their bronchodilatory effects. (Dorland, 28th edition) Xanthine is a metabolite found in or produced by Escherichia coli (K12 strain, MG1655 strain). Xanthine has been reported in Eleutherococcus senticosus, fruit flies, and other organisms with relevant data. Xanthine is a purine base found in most human tissues and fluids, some plants, and some urinary tract stones. It is an intermediate product of the degradation of adenosine monophosphate into uric acid, produced by the oxidation of hypoxanthine. Methylated xanthine compounds, such as caffeine, theobromine, and theophylline, and their derivatives, are used in medicine for their bronchodilatory effects. (Dorland, 28th edition)
Xanthine is a metabolite of the yeast Saccharomyces cerevisiae, present within or produced by it.
It is a purine base found in most human tissues and fluids, some plants, and some urinary tract stones. It is an intermediate product of the degradation of adenosine monophosphate into uric acid, produced by the oxidation of hypoxanthine. Methylated xanthine compounds, such as caffeine, theobromine, and theophylline, and their derivatives, are used in medicine for their bronchodilatory effects. (Dorland, 28th edition)

---

Xanthine-13C,15N2 (CAS 1262670-81-4) is a stable isotope-labeled form of xanthine used as a tracer in metabolic and pharmacokinetic research. It has a molecular formula of C4(13C)H4N2(15N)2O2 and a molecular weight of 155.09. Xanthine is a purine base and an intermediate in the purine degradation pathway. The compound is available as a research-grade standard and is typically stored as a powder at -20°C for up to 3 years. It is not approved for clinical use and is strictly for research purposes only.

C5H4N4O2

152.110859870911

155.03

1262670-81-4

Xanthine;69-89-6

1188

White to off-white solid powder

1.6±0.1 g/cm3

> 300 °C

1.636

-0.7

3

3

0

11

217

0

C1=NC2=C(N1)C(=O)[15NH][13C](=O)[15NH]2

LRFVTYWOQMYALW-UHFFFAOYSA-N

InChI=1S/C5H4N4O2/c10-4-2-3(7-1-6-2)8-5(11)9-4/h1H,(H3,6,7,8,9,10,11)

3,7-dihydropurine-2,6-dione

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.

---

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).

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)]
*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)

---

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
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

---

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.

---

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