The compound itself does not have a primary direct therapeutic target; its major biological activity is mediated through its conversion to UDCA in vivo. As a bile acid, it may also be involved in regulating the composition of the bile acid pool, influencing cholesterol solubility and lipid metabolism in the liver and gallbladder. As a reference standard, it is identified as Ursodeoxycholic Acid EP Impurity H.
3β-Ursodeoxycholic acid targets bile acid receptors and transporters involved in cholesterol homeostasis and bile acid metabolism. As a bile acid, it modulates the enterohepatic circulation of bile acids and affects cholesterol solubility and absorption. It is an anticholelithogenic agent, meaning it prevents the formation of gallstones. The compound may interact with farnesoid X receptor (FXR), the bile acid receptor, and other nuclear receptors involved in lipid and glucose metabolism.

In cell-based studies using Hep G2 cells, 3β-Ursodeoxycholic acid (100 μM) did not show any cytotoxic effects. On the contrary, it demonstrated cytoprotective activity against ethanol-induced cell damage, suggesting a protective role for liver cells under stress conditions.
In vitro studies have demonstrated that 3β-Ursodeoxycholic acid is well absorbed in the intestine following oral administration. As a bile acid, it can modulate cholesterol solubility and bile acid composition in vitro. The compound is used as an impurity standard for pharmaceutical analysis and quality control. It is also used in research on bile acid metabolism and enterohepatic circulation. Further detailed in vitro characterization data, including receptor binding and cellular activity, are limited.

In vivo studies in rats with chronic cholestasis, oral administration of 3β-Ursodeoxycholic acid (2.5 g/kg for 3 weeks) resulted in significant improvement in hepatic biochemistry parameters, specifically decreasing serum levels of alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine transaminase (ALT). However, it did not improve clinical or histological parameters. The compound was found to be completely converted to UDCA in the liver.
In vivo studies have shown that 3β-Ursodeoxycholic acid is well absorbed in the intestine following oral administration. It has been studied at doses of 2.5 g/kg. As an anticholelithogenic agent, it can prevent gallstone formation by modulating bile acid composition and cholesterol solubility. The compound shows good tolerance in animal models. It is used in research on bile acid metabolism, enterohepatic circulation, and cholesterol homeostasis.

A specific non-cellular enzyme/receptor binding protocol for this compound is not provided in the available literature. However, as an EP Impurity Standard for Ursodeoxycholic Acid, it is utilized in analytical method development. A validated RP-HPLC method with refractive index detection is available for the quantitative determination of related impurities in ursodeoxycholic acid API, which can be adapted for this compound.
In vitro enzyme/receptor binding (non-cell) assays for 3β-Ursodeoxycholic acid typically involve bile acid receptor binding studies. Farnesoid X receptor (FXR) or other bile acid receptors are incubated with increasing concentrations of the compound (0.01-100 μM) in binding buffer. Receptor activation can be measured using fluorescence polarization or time-resolved FRET-based assays with labeled coactivator peptides. For enzyme activity, cholesterol 7α-hydroxylase (CYP7A1) activity can be measured in liver microsomes by HPLC. Bile acid binding to serum proteins can be assessed by equilibrium dialysis. IC50 or EC50 values are calculated from dose-response curves.

A cellular assay protocol has been described using Hep G2 cells. The cells were treated with 3β-Ursodeoxycholic acid at a concentration of 100 μM in the presence of 80 μM ethanol. The study aimed to investigate the cytotoxic and cytoprotective effects of the compound. Results indicated that 3β-Ursodeoxycholic acid did not exhibit cytotoxicity and was protective against ethanol-induced cell damage.
For in vitro cell-based assays, hepatocytes or intestinal epithelial cells are cultured in appropriate media. Cells are treated with 3β-Ursodeoxycholic acid at concentrations ranging from 1-100 μM for 24-72 hours. Bile acid receptor activation is assessed by measuring the expression of FXR target genes (e.g., SHP, BSEP, CYP7A1) by qRT-PCR. Cellular cholesterol levels and bile acid composition can be measured by enzymatic assays or LC-MS. Cell viability is assessed by MTT or CCK-8 assays. The compound's effects on bile acid transport can be assessed using cells expressing bile acid transporters.

An animal protocol was conducted in a rat model of chronic cholestasis (bile duct-ligated rats). The compound was administered orally at a dose of 2.5 g/kg body weight, once daily, for a duration of 3 weeks. Blood samples were collected to measure serum biochemical markers (ALP, AST, ALT) to assess liver function, and liver histology was examined.
In vivo animal studies with 3β-Ursodeoxycholic acid typically use rodent models of cholesterol gallstone disease or bile acid metabolism. The compound is administered orally at doses determined from pharmacokinetic studies (e.g., 2.5 g/kg). Gallstone formation is induced by a lithogenic diet, and compound treatment is assessed for prevention of gallstone formation. Bile acid composition in bile, liver, and serum is analyzed by HPLC or LC-MS. Cholesterol levels in bile and serum are measured. Liver histology is examined for signs of toxicity or cholesterol accumulation. The compound's good tolerance and intestinal absorption have been demonstrated.

Metabolism / Metabolites
The known human metabolites of isursodeoxycholic acid include 4-(7-hydroxy-10,13-dimethyl-3-oxo-1,2,4,5,6,7,8,9,11,12,14,15,16,17-tetradecylhydrocyclopenta[a]phenanthrene-17-yl)valerate and 3,6,7-trihydroxycholan-24-acid.

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Specific pharmacokinetic parameters (e.g., half-life, Cmax, AUC) are not detailed in the provided references. However, it is documented that 3β-Ursodeoxycholic acid exhibits good intestinal absorption when administered orally. Following absorption, it undergoes enzymatic isomerization in the intestines and liver to produce UDCA, indicating that its metabolic profile is closely linked to its conversion to the active metabolite.
3β-Ursodeoxycholic acid has a molecular weight of 392.57 g/mol and molecular formula C24H40O4. The compound is well absorbed in the intestine following oral administration. Melting point: 184-186°C. Storage recommendations: 2-8°C. The compound is used as an impurity standard for pharmaceutical analysis and quality control. Pharmacokinetic properties including absorption, distribution, metabolism, and excretion are characteristic of bile acids. The compound is not intended for therapeutic use.

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.
3β-Ursodeoxycholic acid shows good tolerance in preclinical studies. As a bile acid, it is naturally present in the enterohepatic circulation and is generally well-tolerated. At high doses, bile acids may cause gastrointestinal effects. The compound is not intended for therapeutic use and is primarily used as an analytical standard. Standard laboratory safety precautions should be followed when handling the compound.

[1]. Study of human isoursodeoxycholic acid metabolism.Journal of Hepatology. 1997, 26(4), 863-870.

[2]. Metabolism and effects on cholestasis of isoursodeoxycholic and ursodeoxycholic acids in bile duct ligated rats. Biochim Biophys Acta. 2001 Apr 3;1526(1):44-52.

Isursodeoxycholic acid is a dihydroxy-5β-cholanic acid, formed by replacing the β-hydroxy groups at the 3 and 7 positions of (5β)-cholan-24-acid. It is a human metabolite and the conjugate acid of isursodeoxycholic acid salt.
3β-Ursodeoxycholic acid (also known as Isoursodeoxycholic acid) is a bile acid that can be well absorbed in the intestine following oral administration. It has a molecular weight of 392.57 g/mol and molecular formula C24H40O4. It is an anticholelithogenic agent. The compound is used as an impurity standard for pharmaceutical analysis and quality control and in research on bile acid metabolism and enterohepatic circulation. 3β-Ursodeoxycholic acid is not FDA-approved and is intended for research and analytical use only.

C₂₄H₄₀O₄

392.57

392.293

78919-26-3

Ursodeoxycholic acid-2,2,4,4-d4;347841-46-7

127601

White to off-white solid powder

1.128g/cm3

547.1ºC at 760 mmHg

298.8ºC

1.543

4.477

3

4

4

28

605

10

C[C@@]12[C@@H]([C@H](C)CCC(=O)O)CC[C@H]1[C@@H]1[C@@H](O)C[C@@H]3C[C@H](CC[C@]3(C)[C@H]1CC2)O

RUDATBOHQWOJDD-DNMBCGTGSA-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)/t14-,15+,16+,17-,18+,19+,20+,22+,23+,24-/m1/s1

(4R)-4-[(3S,5S,7S,8R,9S,10S,13R,14S,17R)-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

Isoursodeoxycholic acid; 78919-26-3; 3beta-Ursodeoxycholic Acid; 3beta,7beta-Dihydroxy-5beta-cholan-24-oic Acid; 2R6LC4J3N9; 3βUrsodeoxycholic acid; 3β Ursodeoxycholic acid

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)

DMSO : ~100 mg/mL (~254.73 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.37 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (6.37 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
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.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (6.37 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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