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Fiacitabine(also known as NSC 382097; DRG-0077) is a novel, potent and selective inhibitior of DNA replication of herpes simplex virus(HSV) with IC50 values of 2.5 nM and 12.6 nM for HSV1 and HSV2, respectively. Fiacitabine is a pyrimidine nucleoside analog reported to elicit potent anti-VZV activity both in vitro and in vivo. Fiacitabine has potent antiviral activity in vivo against herpes simplex virus types 1 and 2 and cytomegalovirus. Fiacitabine is therapeutically superior to ara-A for the treatment of varicella-zoster virus infections in immunosuppressed subjects.
Physicochemical Properties
| Molecular Formula | C9H11N3O4FI |
| Molecular Weight | 371.10374 |
| Exact Mass | 370.977 |
| CAS # | 69123-90-6 |
| PubChem CID | 50312 |
| Appearance | White to off-white solid powder |
| Density | 2.4±0.1 g/cm3 |
| Boiling Point | 524.6±60.0 °C at 760 mmHg |
| Flash Point | 271.1±32.9 °C |
| Vapour Pressure | 0.0±3.1 mmHg at 25°C |
| Index of Refraction | 1.791 |
| LogP | -0.27 |
| Hydrogen Bond Donor Count | 3 |
| Hydrogen Bond Acceptor Count | 5 |
| Rotatable Bond Count | 2 |
| Heavy Atom Count | 18 |
| Complexity | 430 |
| Defined Atom Stereocenter Count | 4 |
| SMILES | C1=C(C(=NC(=O)N1[C@H]2[C@H]([C@@H]([C@H](O2)CO)O)F)N)I |
| InChi Key | GIMSJJHKKXRFGV-BYPJNBLXSA-N |
| InChi Code | InChI=1S/C9H11FIN3O4/c10-5-6(16)4(2-15)18-8(5)14-1-3(11)7(12)13-9(14)17/h1,4-6,8,15-16H,2H2,(H2,12,13,17)/t4-,5+,6-,8-/m1/s1 |
| Chemical Name | 4-amino-1-((2R,3S,4R,5R)-3-fluoro-4-hydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)-5-iodopyrimidin-2(1H)-one |
| Synonyms | DRG-0077; DRG 0077; DRG0077; FIAC; FOAC; NSC 382097; NSC-382097; NSC382097; Fluoroiodoaracytidine. Fluorviodoaracytidine. |
| HS Tariff Code | 2934.99.9001 |
| Storage |
Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition | Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs) |
Biological Activity
| Targets |
Fiacitabine (FIAC) inhibits herpes simplex virus type 1 (HSV-1), type 2 (HSV-2), and herpes zoster virus (HZV) replication. Its antiviral selectivity is attributed to preferential phosphorylation by the virus-specified thymidine (or pyrimidine nucleoside) kinase, rather than cellular enzymes. [2] |
| ln Vitro |
Fiacitabine (FIAC) suppressed replication of four strains of HSV-1 (Patton, HFEM, MacIntyre, 2931) and two strains of HSV-2 (333, G) by 90% at concentrations ranging from 0.0025 to 0.0126 µM in Vero cell monolayers. [2] Compared to other antiviral drugs against HSV-1 (strain 2931), the 90% effective dose (ED₉₀) for FIAC was substantially lower: acycloguanosine was 0.6 times, arabinosylcytosine was 14.1 times, 5-iododeoxyuridine was 421 times, and arabinosyladenine was 5,263 times higher than the ED₉₀ for FIAC. [2] FIAC inhibited plaque formation of the Ellen strain of HZV in WI-38 cells by 50% at a concentration of 0.01 µM. [2] A thymidine kinase-deficient mutant strain of HSV-1 was about 8,000-fold less susceptible to FIAC (ED₉₀: 78 µM) compared to the wild-type (thymidine kinase-positive) virus, indicating the importance of the viral kinase for its activity. [2] The anti-HSV-1 activity of FIAC was not reversed by equimolar or 10-fold excess concentrations of deoxycytidine. However, high concentrations of thymidine (10-fold excess) partially reversed the antiviral activity (33% reversal at 1 µM FIAC; 19% reversal at 10 µM FIAC). [2] The minimal cytotoxicity of FIAC on normal uninfected cells (WI-38) was completely reversed by the presence of an equimolar concentration of deoxycytidine (e.g., toxicity of 100 µM FIAC reduced from 98% inhibition to 7% inhibition). [2] |
| Enzyme Assay |
Standard DNA polymerase activity assay: The activity of purified DNA polymerases (HSV-1, HSV-2, EBV, human α and β) was assayed in a 50 µl reaction mixture containing Tris-HCl buffer (pH specific to each enzyme), dithiothreitol, MgCl₂, dATP, dTTP, dGTP, [³H]dCTP as the labeled precursor, activated calf thymus DNA template, bovine serum albumin, glycerol, and enzyme. Incubation was at 37°C for 30 min. The reaction was stopped, and acid-insoluble radioactivity was collected on nitrocellulose filters, washed with trichloroacetic acid and ethanol, dried, and counted in a liquid scintillation counter. [1] Kinetics of competitive inhibition: To determine the mode of inhibition and calculate KI values, assays were performed with activated DNA template and [³H]dCTP as the rate-limiting substrate in the presence of increasing concentrations of the inhibitor FIACTP. The data were analyzed using Lineweaver-Burk plots. [1] Alternate substrate assay: To test if FIACTP could be incorporated into DNA, the standard assay was modified by omitting dCTP from the reaction mixture and adding varying concentrations of FIACTP (or araCTP as a control). [³H]dGTP was used as the labeled precursor to monitor DNA synthesis. [1] |
| Cell Assay |
Virus replication inhibition assay: Vero cell monolayers in multi-well plates were inoculated with virus (1 PFU/cell). After a 2-hour absorption period, maintenance medium containing various concentrations of FIAC was added. After 18-20 hours, supernatant was collected, centrifuged, and stored at -70°C. Virus titers were later quantified on fresh Vero cell monolayers in microwell plates. [2] Plaque reduction assay: Monolayers of susceptible cells were inoculated with 10-20 PFU/well. After virus adsorption, the inoculum was washed off, and the cells were overlaid with maintenance medium containing 1% methylcellulose and various concentrations of FIAC. After plaque development, plaques were counted, and the drug concentration required for 50% plaque reduction was calculated. [2] Cellular cytotoxicity assay: Uninfected adherent cells (WI-38, Vero) were plated at 5 x 10⁴ cells/mL/well, and suspension cells (NC-37 lymphoblastoid line) at 4 x 10⁴ cells/mL/well. FIAC was added at final concentrations ranging from 0.1 to 100 µM. After 4 days of culture, adherent cells were harvested using trypsin, and all cell types were mixed with trypan blue dye. Viable cells were counted using a hemacytometer. The concentration causing 50% inhibition of cell replication (ID₅₀) was determined. [2] |
| Toxicity/Toxicokinetics |
Cytotoxicity: In a 4-day assay, Fiacitabine (FIAC) showed minimal cytotoxicity against uninfected normal cell lines. The 50% inhibitory dose (ID₅₀) was 5 µM for Vero cells, 4 µM for WI-38 human fibroblasts, and 10 µM for NC-37 human lymphoblastoid cells. [2] |
| References |
[1]. Selective inhibition of DNA replication in herpes simplex virus infected cells by 1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-5-iodocytosine. J Biol Chem. 1982 Oct 25;257(20):11879-82. [2]. 2'-fluoro-5-iodo-aracytosine, a potent and selective anti-herpesvirus agent. Antimicrob Agents Chemother. 1980 May;17(5):803-6. |
| Additional Infomation |
Fiacitabine has been used in trials studying the treatment of HIV Infections and Cytomegalovirus Infections. Fiacitabine is a pyrimidine nucleoside analog with activity against various herpesviruses. Fiacitabine is converted to its triphosphate form in vivo and inhibits viral DNA polymerase. Fiacitabine (FIAC) is a pyrimidine nucleoside analog, specifically a 5-substituted 1-(2'-deoxy-2'-fluoro-β-D-arabinofuranosyl) cytosine. [2] It is a potent and selective anti-herpesvirus agent, equally effective against HSV-1, HSV-2, and HZV. [2] Its selectivity is proposed to result from preferential phosphorylation by the virus-specified thymidine/pyrimidine nucleoside kinase in infected cells, leading to selective activation and antiviral activity. [2] The hydrochloride salt of FIAC is highly soluble in water (>150 mg/mL). [2] The minimal cytotoxicity observed in normal cells can be reversed by deoxycytidine, suggesting a potential strategy to manage toxicity in vivo without compromising antiviral efficacy. [2] |
Solubility Data
| Solubility (In Vitro) | DMSO : ~37 mg/mL (~99.70 mM) |
| Solubility (In Vivo) |
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. Injection Formulations (e.g. IP/IV/IM/SC) 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). 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) Oral Formulations 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). 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 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. (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 2.6947 mL | 13.4735 mL | 26.9469 mL | |
| 5 mM | 0.5389 mL | 2.6947 mL | 5.3894 mL | |
| 10 mM | 0.2695 mL | 1.3473 mL | 2.6947 mL |