In prostate cancer cell lines, abacavir (15 and 150 μM, 0-120 h) monosulfate suppresses cell proliferation, modifies the expression of LINE-1 mRNA, influences the progression of the cell cycle, and promotes senescence[1]. Abacavir monosulfate (15 and 150 μM, 18 h) dramatically decreases cell migration and prevents cell invasion[1]. Fat apoptosis is induced by abacavir monsulfate[4].

Abacavir (0.7–7.5 μg/mL, 100 μL, intrascrotal injection; 100 and 200 mg/kg, po; 4 h) increased the formation of thrombus in a dose-dependent manner[2]. In high-risk mice carrying medulloblastoma, abacavir (50 mg/kg/d; ip; 14 days) monosulfate combined with 0.1 mg/kg/d Decitabine improves survival[3].

Cell Proliferation Assay[1]
Cell Types: PC3, LNCaP and WI-38
Tested Concentrations: 15 and 150 μM
Incubation Duration: 0, 24, 48, 72 and 96 h
Experimental Results: demonstrated a dose-dependent growth inhibition on PC3 and LNCaP.

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Cell Cycle Analysis[1]
Cell Types: PC3 and LNCaP
Tested Concentrations: 150 μM
Incubation Duration: 0, 18, 24, 48, 72, 96 and 120 h
Experimental Results: Caused a very high accumulation of cells in S phase in PC3 and LNCaP cells, and G2/M phase increment was observed in PC3 cells.

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Cell Migration Assay [1]
Cell Types: PC3 and LNCaP
Tested Concentrations: 15 and 150 μM
Incubation Duration: 18 h
Experimental Results: Dramatically decreased cell migration. Cell Invasion Assay[1]
Cell Types: PC3 and LNCaP
Tested Concentrations: 15 and 150 μM
Incubation Duration: 18 h
Experimental Results: Dramatically inhibited cell invision.

Animal/Disease Models: Male mice (9-weeks old, 22-30 g) - wild-type (WT) C57BL/ 6 or homozygous knockout (P2rx7 KO, B6.129P2-P2rx7tm1Gab/J)[2]
Doses: 2.5, 5 and 7.5 μg/mL, 100 μL or 100 and 200 mg/kg
Route of Administration: Intrascrotal or oral administration for 4 h
Experimental Results: Dose-dependently promoted thrombus formation.

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Animal/Disease Models: NSGTM mice, patient-derived xenograft (PDX) cells of non-WNT/non-SHH, Group 3 and of SHH/ TP53-mutated medulloblastoma[3]
Doses: 50 mg/kg/ d with 0.1 mg/kg/d Decitabine
Route of Administration: intraperitoneal (ip)injection, daily for 14 days
Experimental Results: Inhibited tumor growth and enhanced mouse survival.

Absorption, Distribution and Excretion
Following oral administration of a 600-mg dose of radiolabeled abacavir, 82.2% of the dose is excreted in urine and 16% of the dose is excreted in feces. The 5-carboxylic acid metabolite, 5-glucuronide metabolite, and unchanged abacavir accounted for 30, 36, and 1.2%, respectively, of recovered radioactivity in urine; unidentified minor metabolites accounted for 15% of recovered radioactivity in urine.
It is not known whether abacavir is distributed into human milk; the drug is distributed into milk in rats.
Abacavir crosses the placenta in rats.
The oral bioavailability of abacavir is high with or without food; the CSF-to-plasma AUC ratio is approximately 0.3.
For more Absorption, Distribution and Excretion (Complete) data for ABACAVIR SULFATE (7 total), please visit the HSDB record page.

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Metabolism / Metabolites
Abacavir is partially metabolized by alcohol dehydrogenase (to form the 5'-carboxylic acid) and glucuronidation (to form the 5'-glucuronide).
The metabolic fate of abacavir has not been fully determined, but the drug is metabolized in the liver. Abacavir is metabolized by alcohol dehydrogenase to form the 5-carboxylic acid and by glucuronyltransferase to form the 5-glucuronide; these metabolites do not appear to have any antiviral activity. Any involvement of cytochrome p450 isoenzymes in the metabolism of abacavir is limited.
Intracellularly, abacavir is phosphorylated to abacavir monophosphate by adenosine phosphotransferase; abacavir monophosphate is then converted to carbovir monophosphate in a reaction catalyzed by cytosolic enzymes and then to carbovir triphosphate by cellular kinases. Intracellular (host cell) conversion of abacavir to carbovir triphosphate is necessary for the antiviral activity of the drug. The in vitro intracellular half-life of carbovir triphosphate in CD4+ CEM cells is 3.3 hours.

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Biological Half-Life
The in vitro intracellular half-life of carbovir triphosphate /SRP: a metabolite of abacavir sulfate,/ in CD4+ CEM cells is 3.3 hours.
The plasma elimination half-life of abacavir following a single oral dose (given as abacavir sulfate) is about 1.5 hours. In HIV-infected children 3 months to 13 years of age who received 8 mg/kg of abacavir every 12 hours (given as an oral solution containing abacavir sulfate), steady-state plasma elimination half-life averaged 1.3 hours and was essentially the same as that reported after a single dose. Following oral administration of a single 300-mg dose of abacavir to an individual with renal failure (glomerular filtration rate less than 10 mL/minute) undergoing peritoneal dialysis, the plasma elimination half-life of the drug was 1.33 hours.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Abacavir appears in breastmilk in small quantities. Very little information is available on the safety of its use during breastfeeding. Achieving and maintaining viral suppression with antiretroviral therapy decreases breastfeeding transmission risk to less than 1%, but not zero. Individuals with HIV who are on antiretroviral therapy with a sustained undetectable viral load and who choose to breastfeed should be supported in this decision. If a viral load is not suppressed, banked pasteurized donor milk or formula is recommended.
◉ Effects in Breastfed Infants
An HIV-positive mother took a combination tablet containing dolutegravir 50 mg, abacavir sulfate 600 mg and lamivudine 300 mg (Triumeq) once daily. Her infant was exclusively breastfed for about 30 weeks and partially breastfed for about 20 weeks more. No obvious side effects were noted.
◉ Effects on Lactation and Breastmilk
Gynecomastia has been reported among men receiving highly active antiretroviral therapy. Gynecomastia is unilateral initially, but progresses to bilateral in about half of cases. No alterations in serum prolactin were noted and spontaneous resolution usually occurred within one year, even with continuation of the regimen. Some case reports and in vitro studies have suggested that protease inhibitors might cause hyperprolactinemia and galactorrhea in some male patients, although this has been disputed. The relevance of these findings to nursing mothers is not known. The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

[1]. The reverse transcription inhibitor abacavir shows anticancer activity in prostate cancer cell lines. PLoS One. 2010 Dec 3;5(12):e14221.

[2]. Abacavir Induces Arterial Thrombosis in a Murine Model. J Infect Dis. 2018 Jun 20;218(2):228-233.

[3]. Enhanced Survival of High-Risk Medulloblastoma-Bearing Mice after Multimodal Treatment with Radiotherapy, Decitabine, and Abacavir. Int J Mol Sci. 2022 Mar 30;23(7):3815.

[4]. Improvements in lipoatrophy, mitochondrial DNA levels and fat apoptosis after replacing stavudine with abacavir or zidovudine. AIDS. 2005 Jan 3;19(1):15-23.

Abacavir (brand name: Ziagen) is a prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of HIV infection in adults, children, and infants. Abacavir is always used in combination with other HIV medicines. 
See also: Abacavir Sulfate (annotation moved to).

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Drug Indication
Ziagen is indicated in antiretroviral combination therapy for the treatment of Human Immunodeficiency Virus (HIV) infection in adults, adolescents and children. The demonstration of the benefit of Ziagen is mainly based on results of studies performed with a twice daily regimen, in treatment-naïve adult patients on combination therapy. Before initiating treatment with abacavir, screening for carriage of the HLA-B*5701 allele should be performed in any HIV-infected patient, irrespective of racial origin. Abacavir should not be used in patients known to carry the HLA-B*5701 allele.

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Mechanism of Action
Like dideoxynucleoside reverse transcriptase inhibitors (e.g., didanosine, lamivudine, stavudine, zalcitabine, zidovudine), the antiviral activity of abacavir appears to depend on intracellular conversion of the drug to a 5-triphosphate metabolite; thus, carbovir triphosphate (carbocyclic guanosine triphosphate) and not unchanged abacavir appears to be the pharmacologically active form of the drug. Substantial differences exist in the rates at which human cells phosphorylate various nucleoside antiviral agents and in the enzymatic pathways involved.
Enzymatic conversion of abacavir to carbovir triphosphate appears to be complex and involves certain steps and enzymes that differ from those involved in the enzymatic conversion of dideoxynucleoside reverse transcriptase inhibitors. Abacavir is phosphorylated by adenosine phosphotransferase to abacavir monophosphate, which is converted to carbovir monophosphate by a cytosolic enzyme. Subsequently, carbovir monophosphate is phosphorylated by cellular kinases to carbovir triphosphate. Abacavir is not a substrate for enzymes (i.e., thymidine kinase, deoxycytidine kinase, adenosine kinase, mitochondrial deoxyguanosine kinase) known to phosphorylate other nucleoside analogs. Because phosphorylation of abacavir depends on cellular rather than viral enzymes, conversion of the drug to the active triphosphate derivative occurs in both virus-infected and uninfected cells. Carbovir triphosphate is a structural analog of deoxyguanosine-5-triphosphate (dGTP), the usual substrate for viral RNA-directed DNA polymerase. Although other mechanisms may be involved in the antiretroviral activity of the drug, carbovir triphosphate appears to compete with deoxyguanosine-5-triphosphate for viral RNA-directed DNA polymerase and incorporation into viral DNA. Following incorporation of carbovir triphosphate into the viral DNA chain instead of deoxyguanosine-5-triphosphate, DNA synthesis is prematurely terminated because the absence of the 3-hydroxy group on the drug prevents further 5 to 3 phosphodiester linkages.
The complete mechanism(s) of antiviral activity of abacavir has not been fully elucidated. Following conversion to a pharmacologically active metabolite, abacavir apparently inhibits replication of retroviruses, including human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2), by interfering with viral RNA-directed DNA polymerase (reverse transcriptase). The drug, therefore, exerts a virustatic effect against retroviruses by acting as a reverse transcriptase inhibitor.

C14H20N6O5S

384.410800933838

384.121

216699-07-9

Abacavir;136470-78-5;Abacavir sulfate;188062-50-2;Abacavir hydrochloride;136777-48-5

9843042

White to off-white solid

5

10

4

26

496

2

S(O)(O)(=O)=O.N(C1CC1)C1N=C(N)N=C2N([C@H]3C=C[C@@H](CO)C3)C=NC=12

MBFKCGGQTYQTLR-SCYNACPDSA-N

InChI=1S/C14H18N6O.H2O4S/c15-14-18-12(17-9-2-3-9)11-13(19-14)20(7-16-11)10-4-1-8(5-10)6-21;1-5(2,3)4/h1,4,7-10,21H,2-3,5-6H2,(H3,15,17,18,19);(H2,1,2,3,4)/t8-,10+;/m1./s1

[(1S,4R)-4-[2-amino-6-(cyclopropylamino)purin-9-yl]cyclopent-2-en-1-yl]methanol;sulfuric acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

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

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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