Fluorouracil, commonly known as 5-Fluorouracil (5-FU) or 5-FU, is a synthetic pyrimidine analogue and antimetabolite used as an antineoplastic agent. It has the molecular formula C₄H₃FN₂O₂, molecular weight 130.08 g/mol, and CAS Registry Number 51-21-8.
Fluorouracil is structurally related to uracil, with a fluorine atom replacing hydrogen at the 5-position. It is used in pharmaceutical products administered by different routes, including intravenous administration and topical preparations, depending on the approved product and indication.
IUPAC Name: 5-Fluoro-1H-pyrimidine-2,4-dione.
Fluorouracil is used as an antineoplastic agent in pharmaceutical products for the treatment of several cancers. Topical formulations are also used for certain dermatological conditions, including actinic keratosis and selected superficial skin cancers. The approved indication depends on the formulation and jurisdiction.
Fluorouracil is converted intracellularly into active metabolites that interfere with nucleic-acid synthesis. A major mechanism involves inhibition of thymidylate synthase, reducing thymidine availability required for DNA synthesis. Its metabolites can also become incorporated into RNA and interfere with RNA processing and function.
Fluorouracil is described as a white to nearly white crystalline powder and is practically odorless.
| Parameter | Specification |
|---|---|
| Appearance | White to off-white crystalline powder |
| Identification | IR & HPLC compliant |
| Assay (HPLC) | 98.0% – 102.0% |
| Loss on Drying | NMT 1.0% |
| Residue on Ignition | NMT 0.5% |
| Heavy Metals | NMT 20 ppm |
| pH (1% Solution) | 2.0 – 4.0 |
| Individual Impurity | NMT 0.5% |
| Total Impurities | NMT 1.0% |