Title: Cytarabine
CAS Registry Number: 147-94-4
CAS Name: 4-Amino-1-b-D-arabinofuranosyl-2(1H)-pyrimidinone
Additional Names: 1-b-D-arabinofuranosylcytosine; Ara-C; b-cytosine arabinoside; aracytidine
Manufacturers' Codes: CHX-3311; U-19920
Trademarks: Alexan (Ebewe); Aracytine (Pfizer); Cytosar (Pharmacia & Upjohn); Depocyte (Pharmacia); Udicil (Pharmacia & Upjohn)
Molecular Formula: C9H13N3O5
Molecular Weight: 243.22
Percent Composition: C 44.44%, H 5.39%, N 17.28%, O 32.89%
Literature References: Nucleoside analog; converted by cellular kinases into the active metabolite, AraCTP. Prepn: J. H. Hunter, US 3116282 (1963 to Upjohn); T. Y. Shen et al., J. Org. Chem. 30, 835 (1965). NMR soln structure of Ara-C within a DNA dodecamer: B. I. Schweitzer et al., Biochemistry 33, 11460 (1994). Crystal structure of complex with human topoisomerase I: J. E. Chrencik et al., J. Biol. Chem. 278, 12461 (2003). Clinical pharmacology and toxicology: R. C. Donehower et al., Cancer Treat. Rep. 70, 1059 (1986). Symposium on clinical pharmacology, pharmacokinetics and efficacy in leukemia: Scand. J. Haematol. 36, Suppl. 44, 1-74 (1986). Review of development of a high dose treatment for acute myeloid leukemia: R. L. Capizzi, Invest. New Drugs 14, 249-256 (1996); of cellular metabolism and mechanism of action: S. Grant, Adv. Cancer Res. 72, 197-233 (1998).
Properties: Crystals from ethanol, mp 212-213°. [a]D24 +153° (c = 0.5 in water). uv max at pH 2: 281.0, 212.5 nm (e 13171, 10230); at pH 12: 272.5 nm (e 9259).
Melting point: mp 212-213°
Optical Rotation: [a]D24 +153° (c = 0.5 in water)
Absorption maximum: uv max at pH 2: 281.0, 212.5 nm (e 13171, 10230); at pH 12: 272.5 nm (e 9259)
Therap-Cat: Antineoplastic.
Keywords: Antineoplastic; Antimetabolites; Pyrimidine Analogs.
Cythioate Cytidine Cytisine Cytochalasins Cytochrome c

Cytarabine ball-and-stick.png
Systematic (IUPAC) name
4-amino-1-[(2R,3S,4R,5R)-3,4-dihydroxy-5- (hydroxymethyl)oxolan-2-yl] pyrimidin-2-one
Clinical data
Trade names Cytosar-U
AHFS/ monograph
MedlinePlus a682222
Pregnancy cat. D (AU) D (US)
Legal status Prescription only
Routes Injectable (intravenous injection or infusion, intrathecal, or subcutaneously)
Pharmacokinetic data
Bioavailability 20% oral
Protein binding 13%
Metabolism Liver
Half-life biphasic: 10 min, 1-3 hr
Excretion Renal
CAS number 147-94-4 YesY
ATC code L01BC01
PubChem CID 6253
DrugBank DB00987
ChemSpider 6017 YesY
UNII 04079A1RDZ YesY
KEGG D00168 YesY
ChEBI CHEBI:28680 YesY
Chemical data
Formula C9H13N3O5 
Mol. mass 243.217 g/mol
 YesY (what is this?)  (verify)

Cytarabine or cytosine arabinoside (Cytosar-U or Depocyt) is a chemotherapy agent used mainly in the treatment of cancers of white blood cells such as acute myeloid leukemia (AML) and non-Hodgkin lymphoma.[1] It is also known as Ara-C (Arabinofuranosyl Cytidine).[2] It kills cancer cells by interfering with DNA synthesis.

It is called cytosine arabinoside because it combines a cytosine base with an arabinose sugar. Cytosine normally combines with a different sugar, deoxyribose, to form deoxycytidine, a component of DNA. Certain sponges, where it was originally found, use arabinoside sugars to form a different compound (not part of DNA). Cytosine arabinoside is similar enough to human cytosine deoxyribose (deoxycytidine) to be incorporated into human DNA, but different enough that it kills the cell. This mechanism is used to kill cancer cells. Cytarabine is the first of a series of cancer drugs that altered the sugar component of nucleosides. Other cancer drugs modify the base.[3]