Metabolism / Metabolites
Isoursodeoxycholic acid has known human metabolites that include 4-(7-Hydroxy-10,13-dimethyl-3-oxo-1,2,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydrocyclopenta[a]phenanthren-17-yl)pentanoic acid and 3,6,7-Trihydroxycholan-24-oic acid.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Ursodiol is naturally present in human milk. Because of the low levels of ursodiol (ursodeoxycholic acid) in breastmilk after exogenous administration, amounts ingested by the infant are small and are not expected to cause any adverse effects in breastfed infants. Ursodiol has been given directly to newborns to safely and successfully treat prolonged neonatal jaundice. No special precautions are required.
◉ Effects in Breastfed Infants
One breastfed (extent not stated) infant developed normally over the first 6 months of life during maternal ursodiol therapy of 750 to 1000 mg daily.
Seven women who were taking ursodiol 14 mg/kg daily near term and postpartum. They reported no adverse reactions in their breastfed infants during the early postpartum period.
A mother receiving oral ursodiol 250 mg 3 times daily for primary biliary cirrhosis reportedly breastfed her infant normally, although the extent and duration of breastfeeding was not stated.
A woman with primary biliary cirrhosis developed severe pruritus and elevated serum bile acids 3 weeks postpartum. Ursodiol was started at a dose of 500 mg (7.5 mg/kg) daily, increasing to 1500 mg (25 mg/kg) daily over the next 8 weeks. Psychomotor development of her breastfed (extent not stated) infant was normal, and no apparent side effects were observed in the infant.
A retrospective review of the medical records of pregnant patients at a hospital in Ankara, Türkiye who had a diagnosis of primary biliary cirrhosis found 8 patients who took ursodiol postpartum in doses of 13–15 mg/kg daily. “Most” of the patients breastfed their infants (extent not stated). No infant side effects were reported.
A woman was breastfeeding her 8-day-old preterm infant 10 times daily for about 15 minutes each time. The infant was born by cesarean section at 34 weeks of gestation with a weight of 3600 grams. She was diagnosed with cholestasis, type 1 diabetes, and hypothyroidism. She was treated with ursodiol 500 mg daily, insulin levemir and aspart, and levothyroxine. She was also taking cefuroxime, flurbiprofen, a combination of acetaminophen, propyphenazone, and caffeine. The mother took the ursodiol for a total of 12 days, cefuroxime and the analgesic combination for 10 days and flurbiprofen for 15 days. No adverse effects were noticed during the period of ursodiol treatment.
Twenty nursing mothers were taking ursodiol for cholestasis in daily dosages of 500 to 1500 mg or 13 to 15 mg/kg, depending on the condition. Ursodiol was discontinued 3 days postpartum. No apparent side effects were observed in any newborn infant based on standard clinical examination during early postnatal period, and no deterioration in postnatal development was observed during routine 1-year follow-up on routine pediatric examinations.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

[1]. Study of human isoursodeoxycholic acid metabolism.Journal of Hepatology.Volume 26, Issue 4, April 1997, Pages 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.

Isoursodeoxycholic acid is a dihydroxy-5beta-cholanic acid that is (5beta)-cholan-24-oic acid substituted by beta-hydroxy groups at positions 3 and 7. It has a role as a human metabolite. It is a conjugate acid of an isoursodeoxycholate.

C₂₄H₄₀O₄

392.57

392.293

78919-26-3

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

127601

Typically exists as solid at room temperature

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 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.)