Rac1

Azathioprine (oral gavage, 25–400 mg/kg, daily, 10 days) can cause apoptosis in female CD-1 and ICR mice and has a dose-dependent effect on bone marrow cells, red blood cells, peripheral blood cytokines, and other relevant parameters[3].

Cell Line: Rat hepatocytes, Human hepatocytes
Concentration: 0-50 μM
Incubation Time: 24-48 hours
Result: Showed the decrease in cell viability and intracellular GSH levels in rat hepatocytes as low concentration of 0.5 μM but no significant decrease in cell viability at concentrations below 50 μM as well as GSH depletion was obviously noted at a concentration as low as 1 μM in human hepatocytes.

Outbred female CD-1 mice, Female ICR mice
25-400 mg/kg
Oral gavage; everyday; 10days

Absorption, Distribution and Excretion
Oral azathioprine is well absorbed, with a Tmax of 1-2h. Further data regarding the absorption of azathioprine is not readily available.
Azathioprine and mercaptopurine are not detectable in urine after 8 hours. Further data regarding the route of elimination of azathioprine are not available.
Data regarding the volume of distribution of azathioprine is not readily available.
Data regarding the clearance of azathioprine is not readily available.
Azathioprine and mercaptopurine are moderately bound to plasma proteins and are partially dialyzable. They are rapidly removed from the blood by oxidation or methylation in the liver and/or erythrocytes. Renal clearance is of little impact in biological effectiveness or toxicity, but dose reduction is practiced in patients with renal failure.
Azathioprine is well absorbed orally and reaches maximum blood levels within 1 to 2 hours after administration.
Azathioprine is well absorbed from the gastrointestinal tract and has an oral bioavailibility of approximately 60%.
Azathioprine is rapidly cleared from the blood; both azathioprine and mercaptopurine are approximately 30% bound to serum proteins, both appear dialyzable, and both appear to cross the placenta.
The metabolites are excreted in the urine, largely as 6-mercaptopurine. Less than 2% of azathioprine and 20 to 40% of 6-mercaptopurine are excreted as unchanged drugs in the urine.

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Metabolism / Metabolites
Azathioprine is converted to 6-mercaptopurine nonenzymatically. 6-mercaptopurine is then metabolized to 6-methylmercaptopurine by thiopurine methyltransferase, 6-thiouric acid by xanthine oxidase, or 6-thiosine-5'-monophosphate by hypoxanthine phosphoribosyltransferase. 6-thiosine-5'-monophosphate is metabolized to 6-methylthiosine-5'-monophosphate by thiopurine methyltransferase or 6-thioxanthylic acid by inosine monophosphate dehydrogenase. 6-thioxanthylic acid is metabolized by guanosine monophosphate synthetase to 6-thioguanine monophosphate, the first of the 6-thioguanine nucleotides. 6-thioguanine monophosphate is phosphorylated to produce the remaining 6-thioguanine nucleotides, 6-thioguanine diphosphate and 6-thioguanine triphosphate.
Orally administered azathioprine is rapidly divided in vivo to form 6-mercaptopurine.
Metabolized in vivo to 6-mercaptopurine, q.v.
Azathioprine is metabolized to 6-mercaptopurine.
Primarily converted to the active metabolites 6-mercaptopurine and 6-thioinosinic acid via a non-enzymatica process and glutathione transferases. Activation of 6-mercaptopurine occurs via hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and a series of multi-enzymatic processes involving kinases to form 6-thioguanine nucleotides (6-TGNs) as major metabolites
Route of Elimination: Both compounds are rapidly eliminated from blood and are oxidized or methylated in erythrocytes and liver; no azathioprine or mercaptopurine is detectable in urine after 8 hours.

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Biological Half-Life
The half life of azathioprine is approximately 5 hours.
The elimination half-life of azathioprine is approximately 12 to 15 minutes, and that of 6-mercaptopurine is approximately 30 minutes to 4 hours. The total boby clearance of azathioprine is 60 ml/min/kg, and that of 6-mercaptopurine, 10 ml/min/kg.
The half-life of azathioprine itself is about 10 minutes, and that for mercaptopurine is about an hour.

Toxicity Summary
IDENTIFICATION: Group: Other Immunosuppressive agents. Azathioprine: pale yellow, odorless powder. The drug is insoluble in water and very slightly soluble in ethanol. HUMAN EXPOSURE: Summary: Main risks and target organs: Azathioprine is a myelotoxic and hepatotoxic immunosuppressive agent. Bone marrow and liver are the main targets but gastrointestinal tract, kidney, lungs, CNS and skin may also be affected. Transient gastroenteritis may be observed with massive overdose. Leukopenia is the main toxic effect which may occur during azathioprine therapy and in the overdose patient. Liver and kidney function tests may be altered but usually returned to normal after discontinuation of the drug. Summary of clinical effects: Oral ulceration occurs rarely with therapeutic doses but may be seen with large doses. Gastrointestinal disturbances such as nausea, vomiting, abdominal pain and diarrhea can appear mainly at higher doses. Acute pancreatitis was also reported following long term azathioprine treatment. Suppression of the bone marrow mainly leukopenia and occasionally pancytopenia may be seen after therapeutic doses and overdoses of azathioprine. Septic shock due to this immunosuppression may occur. Hepatic dysfunction (hepatocellular and cholestatic), venocclusive disease and hemangioma of the liver following azathioprine therapy were documented. Acute restrictive lung disease, interstitial nephritis and a case of progressive leukoencephalopathy after 4 years azathioprine therapy were reported. Skin rash, alopecia and urticaria and a case of palmar-plantar erythema with desquamation and pain were also documented. Diagnosis: Diagnosis of azathioprine overdose is based on history of the drug taken and clinical findings mainly gastrointestinal dysfunction, leukopenia and liver dysfunction. Peripheral cell blood counts and liver function tests are required. Estimation of 6-thioguanine nucleotide, a cytotoxic metabolite of azathioprine in red blood cell may confirm the diagnosis and could also be used to predict bone marrow toxicity of azathioprine. Indications: Uses: Azathioprine is used as an adjunct for the prevention of the rejection of kidney allografts. The drug is used in conjunction with other immunosuppressive therapy including local radiation therapy, corticosteroids, and other cytotoxic agents. Azathioprine may be used for the treatment of conditions which involve derangement of the immune system including chronic active hepatitis, severe rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, pemphigus vulgaris, polyarteritis nodosa, acquired hemolytic anemia, Crohn's disease and idiopathic thrombocytopenia. Contraindications: Azathioprine is contraindicated in patients who are hypersensitive to the drug. Azathioprine is also contraindicated in those patients with renal failure, impaired hepatic function and in pregnant women. Routes of entry: Oral: Azathioprine is usually administered orally. Parenteral: Following renal transplantation, azathioprine may initially be given intravenously to patients unable to tolerate oral medication. Oral therapy should replace parenteral therapy as soon as possible. Kinetics: Absorption by route of exposure: Azathioprine is readily absorbed from the gastrointestinal tract with only 12.6% of the dose being detected in the stool over a 48 hour period. Distribution by route of exposure: Azathioprine is rapidly distributed throughout the body with peak plasma concentrations being reached at 1 to 2 hours after dosing. Small amounts of azathioprine bind to plasma proteins (to a maximum of 30%) and only very small amounts enter the brain. Azathioprine crosses the placenta and trace amounts of the 6-mercaptopurine metabolite have been detected in fetal blood. Biological half-life by route of exposure: The plasma half-life of azathioprine is 3 to 5 hours. Metabolism: Azathioprine is metabolized in vivo to mercaptopurine, apparently by sulfhydryl compounds such as glutathione. Mercaptopurine is oxidized and methylated to several derivatives among which 6-thiouric acid predominates; the proportion of metabolites varies amongst individuals. The fate of the nitromethylimidazole portion of azathioprine has not been completely elucidated. Small amounts of azathioprine are also split to give 1-methyl-4-nitro-5-thioimidazole. The active metabolites, 6-thioguanine nucleotides, responsible for the therapeutic action, are formed intracellularly and appear to have very long half-lives. Elimination by route of exposure: The metabolites of azathioprine are excreted by the kidneys; only small amounts of azathioprine and mercaptopurine are excreted intact. In the 24 hour period after administration up to 50% of the dose is excreted in the urine with 10% as the parent drug. There is no data concerning azathioprine excretion in breast milk. Pharmacology and toxicology: Mode of action: Toxicodynamics: The principal toxic effect of azathioprine is bone marrow depression manifested by leukopenia, macrocytic anemia, pancytopenia, and thrombocytopenia, which may result in prolongation of clotting time and eventual hemorrhage. Pharmacodynamics: The exact mechanism of immunosuppressive activity of azathioprine has not been determined. Azathioprine which is an antagonist to purine metabolism may inhibit RNA and DNA synthesis. The drug may also be incorporated into nucleic acids resulting in chromosome breaks, malfunctioning of the nucleic acids, or synthesis of fraudulent proteins. The drug may also inhibit coenzyme formation and functioning, thereby interfering with cellular metabolism. Mitosis may be inhibited by the drug. In patients who undergo renal transplantation, azathioprine suppresses hypersensitivities of the cell-mediated type and causes variable alterations in antibody production. Human data: Adults: Severe pancytopenia has been observed in about 1% of the patients. Children: Lymphopenia, decreased IgG and IgM concentrations, cytomegalovirus infection. Cytogenetic damage was observed in human lymphocytes in vitro. Acute myelogenous leukemia and solid tumours have occurred in patients with rheumatoid arthritis who received the drug. Mutagenicity: Azathioprine is mutagenic in animals and humans, chromosomal abnormalities have been documented in humans receiving azathioprine, but the abnormalities were reversed following discontinuance of the drug. Interactions: Azathioprine dose should be reduced 75% when administered with allopurinol, as allopurinol affects the metabolism of mercaptopurine, a metabolite of azathioprine. Azathioprine may reduce the effect of certain neuromuscular blocking agents including curare and related non-depolarizing drugs. Certain cytotoxic agents may be additive or synergistic in producing toxicity when used in conjunction with azathioprine. The Committee on Safety of Medicines have advised that azathioprine and penicillamine should not be used concurrently. The effects of azathioprine and corticosteroids could be synergistic. Azathioprine may reduce the anticoagulant effect of warfarin. ANIMAL/PLANT STUDIES: Studies with animals have shown that the haemopoietic system is affected by azathioprine with depression of granulopoiesis, megakaryocytes and, hence, platelet formation. Reversible hepatoxicity has been observed in dogs. Various teratogenic effects have been observed in rabbits, showing skeletal abnormalities. In mice embryolethalite was observed. Carcinogenicity: Azathioprine is carcinogenic in animals. Teratogenicity: Azathioprine is teratogenic in rabbits and mice when given in dosages equivalent to the human dosage. Abnormalities included skeletal malformations and visceral anomalies. Mutagenicity: Azathioprine is mutagenic in the Ames test.
Azathioprine antagonizes purine metabolism and may inhibit synthesis of DNA, RNA, and proteins. It may also interfere with cellular metabolism and inhibit mitosis. Its mechanism of action is likely due to incorporation of thiopurine analogues into the DNA structure, causing chain termination and cytotoxicity.

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Toxicity Data
The oral LD₅₀ for single doses of azathioprine in mice and rats are 2500 mg/kg and 400 mg/kg, respectively.

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Interactions
Xanthine oxidase, an enzyme of major importance in the catabolism of metabolites of azathioprine, is blocked by allopurinol. If azathioprine and allopurinol are used in the same patient, the azathioprine dose must be decreased to 25 to 33% of the usual dose, but it is best not to use these two drugs together. Adverse effects resulting from coadministration of azathioprine with other myelosuppressive agents or ACE inhibitors include leukopenia, thrombocytopenia, and/or anemia ...
Allopurinol inhibits the principal metabolic pathway of azathioprine, the oxidative metabolism of mercaptopurine by xanthine oxidase. This may lead to toxic accumulation of azathioprine with concomitant bone marrow depression.
Therapeutic use may lead to bone marrow depression, hepatic dysfunction infection, drug fever, rash, urticarial eruption, hypersensitivity vasculitis, nausea, vomiting, and diarrhea, and possibly an increase in non-Hodgkin's lymphoma when used with corticosteroids in rheumatoid arthritis.
Allopurinol-induced inhibition of xanthine oxidase-mediated metabolism may result in greatly increased azathioprine activity and toxicity; concurrent use should be avoided if possible, especially in renal transplant patients, because of the high risk of 6-mercaptopurine (azathioprine metabolite) accumulation and consequent azathioprine toxicity if the transplanted kidney is rejected; if concurrent use is essential, it is recommended that azathioprine dosage be reduced to one quarter to one third of the usual dosage, the patient be carefully monitored, and subsequent dosage adjustments be based on patient response and evidence of toxicity.
For more Interactions (Complete) data for AZATHIOPRINE (8 total), please visit the HSDB record page.

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Non-Human Toxicity Values
LD50 Rat oral 535 mg/kg
LD50 Rat intraperitoneal 300 mg/kg
LD50 Rat intraduodenal 630 mg/kg
LD50 Mouse oral 1389 mg/kg
For more Non-Human Toxicity Values (Complete) data for AZATHIOPRINE (7 total), please visit the HSDB record page.

[1]. Azathioprine in dermatology: the past, the present, and the future. J Am Acad Dermatol, 2006. 55(3): p. 369-89.

[2]. Azathioprine: old drug, new actions. J Clin Invest, 2003. 111(8): p. 1122-4.

[3]. Azathioprine, 6-mercaptopurine in inflammatory bowel disease: pharmacology, efficacy, and safety. Clin Gastroenterol Hepatol, 2004. 2(9): p. 731-43.

Therapeutic Uses
Azathioprine also is indicated in the treatment of other immunological diseases including regional and ulcerative colitis, biliary cirrhosis, systemic dermatomyositis (polymyositis), glomerulonephritis, chronic active hepatitis, systemic lupus erythematosus (SLE), inflammatory myopathy, myasthenia gravis, nephrotic syndrome, pemphigus and pemphigoid. /NOT included in US product labeling/
Azathioprine is indicated for the management of severe, active, and erosive rheumatoid arthritis unresponsive to rest or conventional medications. /Included in US product labeling/
It /azathioprine/ is also also indicated in the prevention of rejection in cardiac, hepatic, and pancreatic transplantation. /NOT included in US product labeling/
Azathioprine is indicated as an adjunct for prevention of rejection in renal homotransplantation. /Included in US product labeling/
For more Therapeutic Uses (Complete) data for AZATHIOPRINE (12 total), please visit the HSDB record page.

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Drug Warnings
Azathioprine is a toxic drug and must be used only under close medical supervision. Other immunosuppressive therapy given concomitantly with azathioprine therapy may increase the toxic potential of the drug.
Azathioprine may also cause rash, infection, drug fever, serum sickness, alopecia, arthralgia, retinopathy, Raynaud's disease, and pulmonary edema. Some of these adverse effects can occur as manifestations of rare hypersensitivity reactions. Azathioprine-induced hypersensitivity reactions are often characterized by a combination of symptoms, including fever, rigors, musculuskeletal symptoms (arthralgias, myalgias), and/or cutaneous effects (generalized erythematous or maculopapular rash with nonspecific inflammatory changes demonstrated on biopsy); pulmonary manifestations (eg, cough and/or dyspnea) and hypotension (which may be severe and, in the presence of fever, mimic septic shock) may also occur.
Hepatotoxicity manifested by increased serum alkaline phosphatase, bilirubin, and/or aminotransferase concentrations may occur in patients receiving azathioprine, principally in allograft recipients. Azathioprine-induced hepatotoxicity following transplantation occurs most frequently within 6 months of transplantation and is generally reversible following discontinuance of the drug. Rare, but life-threatening hepatic veno-occlusive disease has occurred during chronic azathioprine therapy in several renal allograft recipients and in a patient with panuveitis; serious complications, including progressive portal hypertension, progressive liver failure requiring a portacaval shunt, progressive chronic liver failure with portal hypertension and esophageal varices, and/or rapid deterioration resulting in death, occurred in most of these patients. Veno-occlusive disease was associated with cytomegalovirus infection in some of these patients and with use of azathioprine but not with dosage of the drug, type or duration of renal allograft, or type of underlying renal disease. Reports to date suggest that the onset of hepatic veno-occlusive disease generally occurs after 1-2 years of therapy and that the disease occur principally in males. The clinical syndrome is usually manifested initially by jaundice, often followed by the development of ascites and other signs of partal hypertension. Serum alkaline phosphatase and bilirubin concentrations are usually elevated. Prognosis is poor. Because hepatic veno-occlusive disease may result in rapid clincial deterioration, prompt diagnosis and therapeutic intervention are necessary. Many clinicians suggest that liver biopsy to diagnose veno-occlusive disease should be performed in renal allograft recipients receiving azathioprine at the first sign of mild hepatic dysfunction. If veno-occlusive disease is evident, azathioprine therapy should be promptly and permanently discontinued; alternative immunosuppressive therapy should be considered and, if liver failure is progressive anticoagulation, a partacaval shunt, or hepatic allotransplantation should be considered. Hepatotoxicity occurs in less than 1% of patients with rheumatoid arthritis who receive azathioprine.
Nausea, vomiting, anorexia, and diarrhea may occur in patients receiving large doses of azathioprine. Adverse GI effects may be minimized by giving the drug in divided doses and/or after meals. Vomiting with abdominal pain may occur rarely with a hypersensitivity pancreatitis. A GI hypersensitivity reaction characterized by severe nausea and vomiting has been reported. This reaction also may be accompanied by diarrhea, rash, fever, malaise, myalgias, elevations in liver enzymes, and, occasionally, hypotension. Symptoms of GI toxicity most often develop within the first several weeks of azathioprine therapy and are reversible upon discontinuance of the drug. The reaction can occur within several hours after rechallange with a single dose of the drug. Other adverse GI effects include ulceration of the mucous membranes of the mouth, esophagitis with possible ulceration, and steatorrhea.
For more Drug Warnings (Complete) data for AZATHIOPRINE (33 total), please visit the HSDB record page.

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Pharmacodynamics
Azathioprine is an immunosuppressive agent which functions through modulation of rac1 to induce T cell apoptosis, as well as other unknown immunosuppressive functions. It has a long duration of action as it is given daily, and has a narrow therapeutic index. Patients should be counselled regarding the risk of malignancies of the skin and lymphomas.

C9H7N7O2S

277.26

277.038

C, 38.99; H, 2.54; N, 35.36; O, 11.54; S, 11.56

446-86-6

Azathioprine-d3;2702733-53-5;Azathioprine sodium;55774-33-9;Azathioprine-13C4;1346600-71-2

2265

Light yellow to yellow solid powder

1.9±0.1 g/cm3

685.7±55.0 °C at 760 mmHg

243-244°C

368.5±31.5 °C

0.0±2.1 mmHg at 25°C

1.924

0.67

1

7

2

19

354

0

S(C1C2=C(N=C([H])N=1)N=C([H])N2[H])C1=C([N+](=O)[O-])N=C([H])N1C([H])([H])[H]

LMEKQMALGUDUQG-UHFFFAOYSA-N

InChI=1S/C9H7N7O2S/c1-15-4-14-7(16(17)18)9(15)19-8-5-6(11-2-10-5)12-3-13-8/h2-4H,1H3,(H,10,11,12,13)

6-(3-methyl-5-nitroimidazol-4-yl)sulfanyl-7H-purine

BW57-322; BW-57-322; Azathioprine; BW 57-322; BW 57 322; trade name: Imuran; Azasan; Imurel. Abbreviations: AZA; AZTP

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)

Solubility in Formulation 1: ≥ 2.08 mg/mL (7.50 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 20.8 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.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (7.50 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 20.8 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.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (7.50 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 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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