Цитарабин

Химические свойства

A white or almost white, crystalline powder, freely soluble in water, very slightly soluble in alcohol and in methylene chloride.

Использование

Cytarabine USP (Cytosar)is used to treat Acute granulocytic leukemia (adults); acute lymphocytic leukemia (children); Hodgkin’s disease

Показания

Cytarabine (cytosine arabinoside, ara-C, Cytosar-U) is an analogue of the pyrimidine nucleosides cytidine and deoxycytidine. It is one of the most active agents available for the treatment of acute myelogenous leukemia. Cytarabine kills cells in the S-phase of the cycle by competitively inhibiting DNA polymerase. The drug must first be activated by pyrimidine nucleoside kinases to the triphosphate nucleotide ara-cytosine triphosphate (ara-CTP). The susceptibility of tumor cells to cytarabine is thought to be a reflection of their ability to activate the drug more rapidly (by kinases) than to inactivate it (by deaminases).

Определение

ChEBI: A pyrimidine nucleoside in which cytosine is attached to D-arabinofuranose via a beta-N1-glycosidic bond.

Общее описание

Cytarabine is a pyrimidine nucleoside drug that is related toidoxuridine. This agent is primarily used as an anticanceragent for Burkitt lymphoma and myeloid and lymphaticleukemias. Cytarabine blocks the cellular utilization of deoxycytidine,hence inhibiting the replication of viral DNA.Before it becomes active, the drug is converted to monophosphates,diphosphates, and triphosphates, which block DNApolymerase and the C-2 reductase that converts cytidinediphosphate into the deoxy derivative.
The antiviral use of cytarabine is in the treatment of herpeszoster (shingles), herpetic keratitis, and viral infectionsthat resist idoxuridine. Cytarabine is usually administeredtopically. Toxicity occurs on bone marrow, the gastrointestinal(GI) tract, and the kidneys.

Реакции воздуха и воды

Water soluble.

Угроза здоровью

ACUTE/CHRONIC HAZARDS: Very toxic. Hazardous decomposition products. May cause irritation on contact. Teratogen. Mutagen. Central nervous system effects.

Механизм действия

Cytarabine is rapidly metabolized in the liver, kidney, intestinal mucosa, and red blood cells and has a half-life in plasma of only 10 minutes after intravenous bolus injection. The major metabolite, uracil arabinoside (ara-U), can be detected in the blood shortly after cytarabine administration. About 80% of a given dose is excreted in the urine within 24 hours, with less than 10% appearing as cytarabine; the remainder is ara-U.When the drug is given by continuous infusion, cytarabine levels in CSF approach 40% of those in plasma.

Клиническое использование

Cytarabine is used in the chemotherapy of acute myelogenous leukemia, usually in combination with an anthracycline agent, thioguanine, or both. It is less useful in acute lymphoblastic leukemia and the lymphomas and has no known activity against other tumors. It has been used intrathecally in the treatment of meningeal leukemias and lymphomas as an alternative to methotrexate.

Профиль безопасности

Moderate to low toxicity byingestion. Human systemic effects: allergic dermatitis,ataxia, blood changes, central nervous system effectsconjunctive irritation, degenerative brain changes, hearingacuity change, lachrymation, peripheral nervefasciculati

Методы очистки

Purify cytarabin by recrystallisation from aqueous EtOH or a large volume of H2O (it solubility at ~20o is 5%). It has max 212 and 279nm at pH 2 and 272nm at pH 12. It is an acute leukaemic agent. [Walwick et al. Proc Chem Soc (London) 84 1959, Beilstein 25 III/IV 3669.]