Ursodeoxycholic acid-d4 shares the same molecular target as its non-deuterated form, ursodeoxycholic acid. UDCA is a bile acid that exerts its effects through multiple mechanisms, including the reduction of cholesterol saturation in bile, the displacement of toxic bile acids, and the activation of nuclear receptors such as the farnesoid X receptor (FXR) and the vitamin D receptor. It also has cytoprotective and anti-inflammatory effects in hepatocytes and cholangiocytes. The labeled compound is used as a tracer to study the pharmacokinetics and metabolism of UDCA.

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 have an effect on a drug's pharmacokinetics and metabolic properties, it is a cause for concern [1].

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The labeled compound itself does not possess intrinsic pharmacological activity in vitro; its biological activity is identical to that of ursodeoxycholic acid. UDCA has been shown to have cytoprotective effects on hepatocytes, reduce bile acid toxicity, and modulate immune responses. In vitro studies have demonstrated that UDCA can reduce apoptosis and inflammation in liver cells. The labeled compound is used as an internal standard for quantifying UDCA in biological samples, not for evaluating its own pharmacological activity.

Ursodeoxycholic acid-d4 is not used as a therapeutic agent; its non-deuterated form, UDCA, is an orally active bile acid used in the treatment of gallstones and cholestatic liver diseases, including primary biliary cholangitis. UDCA is well-absorbed after oral administration and undergoes enterohepatic circulation. It is metabolized in the liver and excreted in bile. The labeled compound is used in pharmacokinetic studies to accurately measure UDCA concentrations in plasma and other biological matrices.

In vitro receptor binding assays for ursodeoxycholic acid-d4 are not standard, as it is an analytical standard. The activity of its non-deuterated form can be assessed using bile acid receptor activation assays (e.g., FXR). Cells expressing FXR are treated with UDCA, and downstream signaling is measured. The labeled compound is used as an internal standard for LC-MS/MS analysis of UDCA concentrations in biological samples. Quality control includes purity analysis (>98% atom%D).

In vitro cell culture experiments are not performed with ursodeoxycholic acid-d4. When studying the effects of UDCA in cellular systems, the non-labeled compound is used. Hepatocytes or cholangiocytes are treated with UDCA, and apoptosis, inflammation, or bile acid transport are measured. The labeled compound is used as an internal standard for LC-MS/MS analysis of UDCA concentrations in cell culture media or lysates.

In vivo animal studies with ursodeoxycholic acid-d4 are not conducted, as it is an analytical standard. When used in pharmacokinetic studies, the labeled compound serves as an internal standard for the quantification of UDCA in animal plasma or tissue samples. In typical protocols, animals are administered UDCA, and blood and bile samples are collected at various time points. The labeled internal standard is added to the samples before analysis by LC-MS/MS to ensure accurate and precise quantification.

Pharmacokinetic properties of ursodeoxycholic acid-d4 itself are not characterized, as it is not a drug substance. UDCA has a bioavailability of approximately 30-60% after oral administration, with a half-life of 3-5 hours in humans. It undergoes enterohepatic circulation and is metabolized in the liver to taurine and glycine conjugates. The labeled compound is used as an internal standard to accurately quantify UDCA in pharmacokinetic studies.

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
Ursodeoxycholic acid (UCCA) is naturally present in breast milk. Due to the low levels of UCCA in breast milk after exogenous administration, and the minimal intake by the infant, no adverse effects are expected on breastfed infants. Usodeoxycholic acid has been used directly in newborns, safely and effectively treating neonatal jaundice. No special precautions are required.
◉ Effects on Breastfed Infants
One breastfed infant (feeding extent not specified) developed normally in the first 6 months after birth, with the mother taking 750 to 1000 mg of UCCA daily.
Seven women took 14 mg/kg of UCCA daily near delivery and postpartum. They reported no adverse reactions in breastfed infants in the early postpartum period.
A mother with primary biliary cirrhosis reportedly took 250 mg of ursodeoxycholic acid three times daily and breastfed her infant normally, but the extent and duration of breastfeeding were not specified.
A woman with primary biliary cirrhosis developed severe itching and elevated serum bile acids three weeks postpartum. She started taking ursodeoxycholic acid at a dose of 500 mg (7.5 mg/kg) daily, increasing to 1500 mg (25 mg/kg) daily over the next eight weeks. Her breastfed infant (feeding extent not specified) showed normal psychomotor development, and no significant side effects were observed.
A retrospective analysis of medical records of pregnant women diagnosed with primary biliary cirrhosis at a hospital in Ankara, Turkey, found that eight patients took ursodeoxycholic acid postpartum at a dose of 13-15 mg/kg daily. "Most" of these patients breastfed their infants (feeding extent not specified). No side effects were reported in the infants.
A woman breastfed her 8-day-old premature infant 10 times a day, each time for about 15 minutes. The infant was delivered by cesarean section at 34 weeks of gestation, weighing 3600 grams. She was diagnosed with cholestasis, type 1 diabetes, and hypothyroidism. She received ursodeoxycholic acid 500 mg/day, insulin Lantus and aspart, and levothyroxine. She also took cefuroxime, flurbiprofen, and a combination of acetaminophen, disopyrfenone, and caffeine. The mother took ursodeoxycholic acid for 12 days, cefuroxime and the above-mentioned combination analgesics for 10 days, and flurbiprofen for 15 days. No adverse reactions were observed during ursodeoxycholic acid treatment.
Twenty lactating women with cholestasis received ursodeoxycholic acid at a daily dose of 500 to 1500 mg or 13 to 15 mg/kg, depending on their condition. Ursodeoxycholic acid was discontinued 3 days postpartum. Based on standard clinical examinations of newborns in the early postnatal period, no significant side effects were observed in any newborns; no postnatal developmental deterioration was also observed during a one-year follow-up period following routine pediatric examinations.
◉ Effects on breastfeeding and lactation
As of the revision date, no relevant published information was found.

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Ursodeoxycholic acid-d4 is not a therapeutic agent and has not been evaluated for toxicity in humans. Its non-deuterated form, UDCA, is generally well-tolerated, with common side effects including diarrhea, nausea, and abdominal pain. The deuterated compound is for research use only and should be handled with standard laboratory precautions.

[1]. Impact of Deuterium Substitution on the Pharmacokinetics of Pharmaceuticals. Ann Pharmacother. 2019;53(2):211-216.

[2]. Influence of ursodeoxycholic acid on the mortality and malignancy associated with primary biliary cirrhosis: a population-based cohort study. Hepatology. 2007 Oct;46(4):1131-7.

[3]. Use of ursodeoxycholic acid in liver diseases. J Gastroenterol Hepatol. 2001 Jan;16(1):3-14.

[4]. Specific Bile Acids Inhibit Hepatic Fatty Acid Uptake in Mice. Hepatology. 2012 Oct;56(4):1300-10.

[5]. FXR inhibition may protect from SARS-CoV-2 infection by reducing ACE2. Nature. 2022 Dec 5.

Reports indicate that 3,7-dihydroxycholan-24-acid has been found in goose (Anser anser), and relevant data are available for reference.

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Ursodeoxycholic acid-2,2,4,4-d4 is a stable isotope-labeled internal standard used in pharmacokinetic and metabolic studies of UDCA. It is also known as UDCA-d4. The compound is used in analytical method development, method validation, and quality control applications for generic drug products. The incorporation of deuterium allows for accurate quantification of UDCA in biological samples using mass spectrometry.

C24H36D4O4

396.60

396.318

347841-46-7

5645

White to off-white solid powder

4.477

3

4

4

28

605

0

CC(CCC(=O)O)C1CCC2C1(CCC3C2C(CC4C3(CCC(C4)O)C)O)C

RUDATBOHQWOJDD-UHFFFAOYSA-N

InChI=1S/C24H40O4/c1-14(4-7-21(27)28)17-5-6-18-22-19(9-11-24(17,18)3)23(2)10-8-16(25)12-15(23)13-20(22)26/h14-20,22,25-26H,4-13H2,1-3H3,(H,27,28)

4-(3,7-dihydroxy-10,13-dimethyl-2,3,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)pentanoic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

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.)