Absorption, Distribution and Excretion
DRUG TRANSMISSION TO FETUS: TIME TO APPEAR IN FETUS 10 MIN; TIME TO FETAL/MATERNAL CONCN EQUILIBRIUM 40 MIN; FETAL/MATERNAL CONCN RATIO 1.0 /FROM TABLE/
/IN RATS/ ACCUMULATION OF (35)S LABEL WAS FASTER & OCCURRED TO GREATER EXTENT FROM SMALLER DOSE, SUGGESTING PRESENCE OF SATURABLE TRANSPORT MECHANISM. SIMILAR STUDIES WITH (14)C-THIOURACIL HAVE SHOWN ACCUM OF RADIOACTIVITY IN BOTH MATERNAL & FETAL THYROID TISSUES OF RABBITS...
...WITH BOTH LARGE (39 UMOL) & SMALL (1.2 UMOL) DOSES OF (35)S-THIOURACIL, CONSIDERABLE ACCUM OF BOTH TOTAL RADIOACTIVITY & UNMETABOLIZED (35)S-THIOURACIL OCCURS IN THYROID TISSUE RELATIVE TO PLASMA /IN RATS/.
THIOURACIL IS ABSORBED FROM GI TRACT IN RATS... IN RATS ADMIN 5 MG BY IV INJECTION, 30% OF THIOURACIL...RECOVERED FROM CARCASSES AFTER 3 HR & ONLY TRACES AFTER 24 HR.
For more Absorption, Distribution and Excretion (Complete) data for 2-THIOURACIL (7 total), please visit the HSDB record page.

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Metabolism / Metabolites
IN HOMOGENIZED RAT LIVER PREPN FROM FEMALE HOLTZMAN RATS, 28-35% OF THIOURACIL WAS METABOLIZED WITHIN 3 HR. PATHWAY FOR BREAKDOWN OF THIOURACIL WAS SUGGESTED TO BE AS FOLLOWS: URACIL; BETA-UREIDOPROPIONIC ACID, WHICH WAS FURTHER METABOLIZED TO BETA-ALANINE; AMMONIA & CARBON DIOXIDE...

[1]. 2-thiouracil is a selective inhibitor of neuronal nitric oxide synthase antagonising tetrahydrobiopterin-dependent enzyme activation and dimerisation. FEBS Lett, 2000. 485(2-3): p. 109-12.

[2]. Mechanism of selective incorporation of the melanoma seeker 2-thiouracil into growing melanin. J Med Chem, 1996. 39(26): p. 5192-201.

Thiouracil can cause cancer according to The World Health Organization's International Agency for Research on Cancer (IARC).
Thiouracil is a nucleobase analogue that is uracil in which the oxo group at C-2 is replaced by a thioxo group. It has a role as an antithyroid drug and a metabolite. It is a thiocarbonyl compound and a nucleobase analogue. It is functionally related to a uracil.
2-Thiouracil has been reported in Euglena gracilis with data available.
Thiouracil is a sulfur-containing uracil. An established antithyroid drug and highly selective inhibitor of nitric oxide synthase (NOS), thiouracil also covalently binds to dopaquinone, produced by tyrosinase catalyzed oxidation of tyrosine, thereby selectively accumulating in de novo-synthesized melanin in overactive melanin-producing cells and providing a means to localize melanoma cells. (NCI04)
Occurs in seeds of Brassica and Crucifera species. Thiouracil has been used as antithyroid, coronary vasodilator, and in congestive heart failure although its use has been largely supplanted by other drugs. It is known to cause blood dyscrasias and suspected of terato- and carcinogenesis.

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Mechanism of Action
ANTITHYROID DRUGS INHIBIT FORMATION OF THYROID HORMONE LARGELY BY INTERFERING WITH INCORPORATION OF IODINE INTO ORGANIC FORM. THIS IMPLIES THAT THEY INTERFERE WITH OXIDN OF IODIDE ION, BUT ELUCIDATION OF DETAILED MECHANISM... HAMPERED BY INCOMPLETE UNDERSTANDING OF IODIDE-OXIDIZING SYSTEM OF...GLAND. /ANTITHYROID DRUGS/
THIOAMIDE DERIV DO NOT HAVE PERMANENT EFFECT UPON THYROID GLAND BUT INHIBIT HORMONE SYNTHESIS & SECRETION UNTIL SPONTANEOUS REMISSION OCCURS DURING COURSE OF DISEASE. /THIOAMIDE DERIV/

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Therapeutic Uses
Antimetabolites; Antithyroid Agents; Vasodilator Agents
THIOURACIL HAS REPORTEDLY BEEN USED IN HUMAN MEDICINE AS ANTI-THYROID AGENT & IN TREATMENT OF ANGINA PECTORIS & CONGESTIVE HEART FAILURE... HOWEVER, NO EVIDENCE WAS FOUND THAT THIOURACIL PRESENTLY FINDS USE IN US IN THESE APPLICATIONS.
TREATMENT OF HYPERTHYROIDISM; ANGINA PECTORIS; CONGESTIVE HEART FAILURE /PRC: FORMER USES IN US/
MEDICATION (VET): THYROID DEPRESSANT; IN HYPERTHYROIDISM & TO PROMOTE FATTENING

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Drug Warnings
MAIN DRAWBACK TO THERAPY WITH ANTITHYROID DRUGS IS HIGH INCIDENCE OF RELAPSE WHEN TREATMENT IS STOPPED. /ANTITHYROID DRUGS/
PT SHOULD IMMEDIATELY REPORT DEVELOPMENT OF SORE THROAT OR FEVER, WHICH USUALLY HERALDS ONSET OF.../AGRANULOCYTOSIS/. MILD GRANULOCYTOPENIA, IF NOTED, MAY BE SIGN OF THYROTOXICOSIS OR MAY BE FIRST SIGN OF THIS DANGEROUS DRUG REACTION. CAUTION & FREQUENT LEUKOCYTE COUNTS ARE THEN REQUIRED. /THIOAMIDE DERIV/
...WOMEN TAKING THESE AGENTS SHOULD NOT BREAST-FEED THEIR INFANTS. /ANTITHYROID DRUGS/
AT WHAT STAGE IN PREGNANCY...TREATMENT MUST BE INITIATED FOR SUCH EFFECT /FETAL GOITER & HYPOTHYROIDISM/ ON FETUS TO DEVELOP IS NOT KNOWN PRECISELY, BUT IN SOME...INSTANCES MEDICATION WAS NOT BEGUN UNTIL TWO-THIRDS THROUGH PREGNANCY. IT IS FEASIBLE...MIGHT RESULT FROM EVEN LATER MATERNAL ADMIN. /ANTI-THYROID DRUGS/
For more Drug Warnings (Complete) data for 2-THIOURACIL (6 total), please visit the HSDB record page.

C4H4N2OS

128.15236

128.004

141-90-2

2-Thiouracil-13C,15N2

1269845

White to off-white solid powder

1.5±0.1 g/cm3

337.2ºC at 760mmHg

>300 °C(lit.)

157.7ºC

5.45E-05mmHg at 25°C

1.678

-0.28

2

2

0

8

163

0

ZEMGGZBWXRYJHK-UHFFFAOYSA-N

InChI=1S/C4H4N2OS/c7-3-1-2-5-4(8)6-3/h1-2H,(H2,5,6,7,8)

2-sulfanylidene-1H-pyrimidin-4-one

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 : ~50 mg/mL (~390.17 mM)
H2O : ~0.67 mg/mL (~5.23 mM)

Solubility in Formulation 1: ≥ 3.75 mg/mL (29.26 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 37.5 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: ≥ 3.75 mg/mL (29.26 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 37.5 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.)