Hydroxyurea
[CAS# 127-07-1]

Identification

• Classification: Biochemical >> Inhibitor >> Immune inhibitor
• Name: Hydroxyurea
• Synonyms: Hydroxycarbamide
• Molecular Formula: CH₄N₂O₂
• Molecular Weight: 76.05
• CAS Registry Number: 127-07-1
• EC Number: 204-821-7
• SMILES: C(=O)(N)NO

Properties

• Solubility: 15 mg/mL (DMSO), 15 mg/mL (Water ) (Expl.)
• Density: 1.7±0.1 g/cm³, Calc.^*
• Melting point: 140 ºC (Expl.)
• Index of Refraction: 1.543, Calc.^*
• Boiling Point: 222.1±23.0 ºC (760 mmHg), Calc.^*
• Flash Point: 88.1±22.6 ºC, Calc.^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS08 Danger
• Hazard Statements: H340-H360-H361
• Precautionary Statements: P203-P280-P318-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Germ cell mutagenicity	Muta.	1B	H340
Reproductive toxicity	Repr.	2	H361
Carcinogenicity	Carc.	2	H351
Reproductive toxicity	Repr.	1A	H360
Germ cell mutagenicity	Muta.	2	H341
Reproductive toxicity	Repr.	1B	H360

Discovory and Applicatios

Hydroxyurea, with the chemical formula NH₂OH·CO·NH₂, is an organic compound primarily recognized for its medicinal and industrial applications. It was first synthesized in the late 19th century, in 1869, by the German chemist Oscar Krebs, who obtained it through the reaction of urea with hypochlorous acid. The compound is a colorless, crystalline substance, soluble in water, and known for its properties as a potent inhibitor of DNA synthesis.

Hydroxyurea's medical applications were established in the 20th century, particularly in the treatment of certain types of cancer. It was first used as a chemotherapy agent in the 1960s, primarily for the treatment of chronic myelogenous leukemia (CML). Its mechanism of action involves the inhibition of ribonucleotide reductase, an enzyme essential for the synthesis of deoxyribonucleotides, which are the building blocks of DNA. By inhibiting this enzyme, hydroxyurea halts DNA synthesis, making it an effective treatment for rapidly dividing cells in tumors.

The use of hydroxyurea was later expanded to the management of other conditions, including sickle cell disease. Hydroxyurea increases the production of fetal hemoglobin, which can help reduce the frequency of sickle cell crises and alleviate symptoms in affected individuals. It has become a standard treatment for sickle cell anemia, offering significant benefits in terms of reducing pain episodes and hospitalizations. This application is particularly significant because hydroxyurea is the only FDA-approved medication for adults with sickle cell disease in the United States.

In addition to its use in oncology and hematology, hydroxyurea has been employed in the treatment of other conditions, such as psoriasis and polycythemia vera, a disorder characterized by the overproduction of red blood cells. Hydroxyurea is also used off-label for certain types of chronic myeloproliferative disorders, including essential thrombocythemia, to manage elevated platelet counts and reduce the risk of thrombotic events.

Hydroxyurea's utility is not limited to medicine. In industrial applications, hydroxyurea serves as a reagent in the synthesis of various chemicals, including specialty polymers and agricultural products. It is employed in the production of nitrogen-containing compounds used in the manufacture of plastics, resins, and certain fungicides.

The compound is typically administered orally, and its dosage is carefully monitored due to potential side effects, including myelosuppression (reduced bone marrow activity), gastrointestinal disturbances, and an increased risk of infections. Long-term use has also been associated with potential risks of secondary malignancies, although its benefits in managing certain diseases often outweigh these risks when properly monitored.

Despite its effectiveness in treating specific conditions, hydroxyurea requires cautious handling in both clinical and laboratory settings due to its cytotoxic properties. Healthcare providers must follow strict protocols to minimize exposure, especially for healthcare workers who handle the medication.

In conclusion, hydroxyurea is a well-established and versatile compound with a significant history of use in the treatment of cancer and sickle cell disease. Its development as a therapeutic agent has provided substantial benefits in the management of these diseases, contributing to improved patient outcomes. Its ongoing use in both clinical and industrial applications underscores its importance in modern medicine and chemistry.

References

2025. Comparative analysis of various senescence inducers in proximal renal tubular cells. Journal of Pharmaceutical and Biomedical Analysis, 2025, 116571.
DOI: 10.1016/j.jpba.2024.116571

2024. Novel pof1 mutation suppresses the sensitivity to DNA replication inhibitor in fission yeast RecQ helicase mutant. Biochemical and Biophysical Research Communications, 2024, 151014.
DOI: 10.1016/j.bbrc.2024.151014

2024. Hemoglobinopathies Among Patients Referred to Single Centre in Central India: An Observational Study. Indian Journal of Clinical Biochemistry, 2025, 11.
DOI: 10.1007/s12291-023-01151-2