Tegafur is a bioactivator of the hepatic microsomal cytochrome P450 enzyme, 5-FU. The active metabolites 5-fluorodeoxyuridine-monophosphate (FdUMP) and 5-fluorouridine-triphosphate (FUTP), which are embedded in cells and inhibit thymidylate synthase, are produced intracellularly from 5-FU mask. This leads to decreased thymidine synthesis, decreased DNA synthesis, disruption of RNA function, and toxicity to tumor cells.

Absorption, Distribution and Excretion
Tegafur displays a dose-proportional pharmacokinetic properties. Tegafur is rapidly and well absorbed into the systemic circulation, reaching the peak plasma concentration within 1 to 2 hours of administration.
Following oral administration, about less 20% of total tegafur is excreted unchanged in the urine.
The volume of distribution based on apparent volume of distribution and urinary excretion data of tegafur is 16 L/m^2.
No pharmacokinetic data available.

---

Metabolism / Metabolites
Hepatic CYP2A6 is the predominant enzyme that mediates 5-hydroxylation of tegafur to generate 5'-hydroxytegafur. This metabolite is unstable and undergoes spontaneous degradation to form 5-FU, which is an active antineoplastic agent that exerts a pharmacological action on tumours. 5-FU is rapidly metabolised by the liver enzyme dihydropyrimidine dehydrogenase (DPD).
Tegafur has known human metabolites that include 5-Fluorouracil.

---

Biological Half-Life
The elimination half life of tegafur is approximately 11 hours.

Protein Binding
Tegafur is 52.3% bound to serum proteins and 5-FU is 18.4% protein bound.

[1]. Association of right-sided tumors with high thymidine phosphorylase gene expression levels and the response to oral uracil and tegafur/leucovorin chemotherapy among patients with colorectal cancer. Cancer Chemotherapy and Pharmacology. 2012, 70 (2): 285-291.

[2]. Engineering of an antitumor (core/shell) magnetic nanoformulation based on the chemotherapy agent ftorafur. Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2011,384(1-3): 157-163.

[3]. A phase 2 study of a fixed combination of uracil and ftorafur (UFT) and leucovorin given orally in a 3-times-daily regimen to treat patients with recurrent metastatic breast cancer. Cancer. 2010, 116(6): 1440-1445.

[4]. Pharmacokinetics of 5-Fluorouracil in Elderly Japanese Patients with Cancer Treated with S-1 (a Combination of Tegafur and Dihydropyrimidine Dehydrogenase Inhibitor 5-Chloro-2,4-dihydroxypyridine). Drug Metab Dispos. 2009 Jul;37(7):1375-7. doi: 10.1124/dmd.109.027052. Epub 2009 Apr 23.

[5]. Tegafur-uracil.

Tegafur is an organohalogen compound and a member of pyrimidines.
Tegafur (INN, BAN, USAN) is a prodrug of [DB00544] (5-FU), an antineoplastic agent used as the treatment of various cancers such as advanced gastric and colorectal cancers. It is a pyrimidine analogue used in combination therapies as an active chemotherapeutic agent in conjunction with [DB09257] and [DB03209], or along with [DB00544] as [DB09327]. Tegafur is usually given in combination with other drugs that enhance the bioavailability of the 5-FU by blocking the enzyme responsible for its degradation, or serves to limit the toxicity of 5-FU by ensuring high concentrations of 5-FU at a lower dose of tegafur. When converted and bioactivated to 5-FU, the drug mediates an anticancer activity by inhibiting thymidylate synthase (TS) during the pyrimidine pathway involved in DNA synthesis. 5-FU is listed on the World Health Organization's List of Essential Medicines.
Tegafur is a congener of the antimetabolite fluorouracil with antineoplastic activity. Tegafur is a prodrug that is gradually converted to fluorouracil in the liver by the cytochrome P-450 enzyme. Subsequently, 5-FU is metabolized to two active metabolites, 5-fluoro-2-deoxyuridine monophosphate (FdUMP) and 5-fluorouridine triphosphate (FUTP) by both tumor cells and normal cells. FdUMP inhibits DNA synthesis and cell division by inhibiting thymidylate synthase and reducing normal thymidine production, while FUTP inhibits RNA and protein synthesis by competing with uridine triphosphate. (NCI04)
Congener of FLUOROURACIL with comparable antineoplastic action. It has been suggested especially for the treatment of breast neoplasms.

---

Drug Indication
Indicated for the treatment of cancer usually in combination with other biochemically modulating drugs. Indicated in adults for the treatment of advanced gastric cancer when given in combination with [DB00515]. Indicated for the first-line treatment of metastatic colorectal cancer with [DB03419] and calcium folinate.

---

Mechanism of Action
The transformation of 2'-deoxyurindylate (dUMP) to 2'-deoxythymidylate (dTMP) is essential in driving the synthesis of DNA and purines in cells. Thymidylate synthase catalyzes the conversion of dUMP to dTMP, which is a precursor of thymidine triphosphate (TTP), one of the four deoxyribonucleotides required for DNA synthesis. After administration into the body, tegafur is converted into the active antineoplastic metabolite, fluorouracil (5-FU). In tumour cells, 5-FU undergoes phosphorylation to form the active anabolites, including 5-fluorodeoxyuridine monophosphate (FdUMP). FdUMP and reduced folate are bound to thymidylate synthase leading to formation of a ternary complex which inhibits DNA synthesis. In addition, 5-fluorouridine-triphosphate (FUTP) is incorporated into RNA causing disruption of RNA functions.

---

Pharmacodynamics
Tegafur is an antineoplastic agent that belongs in the class of pyrimidine analogues. It interferes with the 2'-deoxythymidylate (DTMP) synthesis in the pyrimidine pathway, resulting in inhibition of DNA synthesis. In a phase III trial investigating the clinical efficacy of S-1 (tegafur/gimeracil/oteracil) in patients with advanced or recurrent gastric cancer, treatment resulted in a high response rate and was associated with a longer overall survival and longer progression-free survival rate when used in combination with cisplatin. In a meta analysis, triple combination therapy consisting of tegafur, gimeracil and oteracil showed longer survival times and well tolerance in patients with advanced gastric cancer. Tegafur and its active metabolites are potent myleosuppressive agents.

C8H9FN2O3

200.17

200.059

17902-23-7

5386

White to off-white solid powder

1.5±0.1 g/cm3

171-173 °C(lit.)

1.557

-0.77

1

4

1

14

316

0

WFWLQNSHRPWKFK-UHFFFAOYSA-N

InChI=1S/C8H9FN2O3/c9-5-4-11(6-2-1-3-14-6)8(13)10-7(5)12/h4,6H,1-3H2,(H,10,12,13)

5-fluoro-1-(oxolan-2-yl)pyrimidine-2,4-dione

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ≥ 48 mg/mL (~239.80 mM)
H2O : ≥ 20 mg/mL (~99.92 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (12.49 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 25.0 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.

---

Solubility in Formulation 2: ≥ 2.5 mg/mL (12.49 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

View More

Solubility in Formulation 3: ≥ 2.5 mg/mL (12.49 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 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

 (Please use freshly prepared in vivo formulations for optimal results.)