Flumequine (formerly R-802; R 802; R802) is a synthetic quinolone, 1^st generation and broad-spectrum chemotherapeutic antibiotic that was once used to treat bacterial infections but has been removed from market. It functions by 15 μM inhibiting topoisomerase II. Both bacterial gyrase and eukaryotic topoisomerase II, which catalyzes the double-strand DNA breakage reaction, are inhibited by flumequine. The inhibitory effects of FL on topoisomerase II are greater than the influence on bacterial gyrase. Twelve clinical isolates of A. salmonicida have minimum inhibitory concentrations (MICs) for memequine ranging from 0.06 μg/mL to 32 μg/mL.

Physicochemical Properties

Molecular Formula	C14H12FNO3
Molecular Weight	261.25
Exact Mass	261.08
Elemental Analysis	C, 64.36; H, 4.63; F, 7.27; N, 5.36; O, 18.37
CAS #	42835-25-6
Related CAS #	42835-25-6
PubChem CID	3374
Appearance	White to off-white solid powder
Density	1.5±0.1 g/cm3
Boiling Point	439.7±45.0 °C at 760 mmHg
Melting Point	253-255°C
Flash Point	219.7±28.7 °C
Vapour Pressure	0.0±1.1 mmHg at 25°C
Index of Refraction	1.646
LogP	2.41
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	1
Heavy Atom Count	19
Complexity	462
Defined Atom Stereocenter Count	0
SMILES	FC1C([H])=C2C(C(C(=O)O[H])=C([H])N3C2=C(C=1[H])C([H])([H])C([H])([H])C3([H])C([H])([H])[H])=O
InChi Key	DPSPPJIUMHPXMA-UHFFFAOYSA-N
InChi Code	InChI=1S/C14H12FNO3/c1-7-2-3-8-4-9(15)5-10-12(8)16(7)6-11(13(10)17)14(18)19/h4-7H,2-3H2,1H3,(H,18,19)
Chemical Name	7-fluoro-12-methyl-4-oxo-1-azatricyclo[7.3.1.05,13]trideca-2,5,7,9(13)-tetraene-3-carboxylic acid
Synonyms	R-802; R 802; R802; Flumequine
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	Topoisomerase II ( IC50 = 15 μM ); Quinolone
ln Vitro	In vitro activity: Flumequine inhibits both bacterial gyrase and eukaryotic topoisomerase II, the latter of which is in charge of the double-strand DNA breakage reaction. The inhibitory effects of FL on topoisomerase II are greater than the influence on bacterial gyrase. [1] The minimum inhibitory concentration (MIC) of flumequine in 12 clinical isolates of A. salmonicida ranges from 0.06 μg/mL to 32 μg/mL. For the most resistant isolates, methamphetamine exhibits high E(max) values of 16, indicating a significant contribution of efflux to the resistance phenotype. The association between high E(max) values and a significantly lower level of accumulation is confirmed by flumequine accumulation experiments. [2]
ln Vivo	Flumequine (4000 ppm, oral diet) causes dose-dependent DNA damage in adult mice's stomach, colon, and bladder three hours after administration, but not twenty-four hours later.[1] Flumequine has a 44.7% bioavailability rate in Atlantic salmon after medicated feed is given orally. After being administered intravenously to Atlantic salmon, memequine causes distribution volumes at steady state of 3.5 L/kg, elimination half-life (t 1/2) of 22.8 hours, and area under plasma drug concentration-time curve (AUC) of 140 μg×hours/mL.[3] For the aquatic weed Lythrum salicaria L., memequine (100 mg/L) decreases the mean number of secondary roots, hypocotyle, cotyledon, and root length.[4] The oral dosage of flumequine (10 mg/kg) causes the steady-state volumes of distribution (Vss) to be 2.41 L/kg for cod and 2.15 L/kg for wrasse after intravenous entry. After administering 10 mg/kg of flumequine orally, the total body clearances (Cl) for cod and wrasse are 0.024 L/h.kg and 0.14 L/h.kg, respectively, and the elimination half-lives (t1/2 λ z) are calculated to be 75 hours. Flumequine administered orally results in oral bioavailabilities (F) of 65% for cod and 41% for wrasse.[5]
Cell Assay	The Chinese hamster lung cell line CHL/IU is routinely cultured in monolayer form at 37°C in a 5% CO2 environment using Dulbecco's modified MEM medium supplemented with 10% fetal bovine serum. For one hour, exponentially growing cells are exposed to a solution of flumequine (R-802) dissolved in DMSO. The dose range is selected to extract both severely damaged and undamaged cells. After being treated with Flumequine (R-802) the cells are embedded in 1% saline-dissolved GP42 agarose. For every dosage, the number and viability of cells are ascertained.
Animal Protocol	Once a week has passed for acclimatization, 4 and 7 week old male ddY infants and young adults are used. At less than 500 mg/kg, groups receive a single oral dose of flumequine (R-802). Eight organs—the stomach, colon, liver, kidney, bladder, lung, brain, and bone marrow—are removed from adult mice following their sacrifice three and twenty-four hours of therapy. Liver removal occurs when young mice are sacrificed three and twenty-four hours after treatment. Flumequine (R-802) genotoxicity in the developing liver of adult mice is investigated in a different study. The left lateral lobe, left medial lobe, and right lateral lobe of the liver are removed from male mice that are 8 weeks old after they are given ether anesthesia for this purpose. Mice are given Flumequine (R-802) orally once every four days following hepatectomy. After 3 hours of FL treatment, they are sacrificed, and samples of their regenerated livers are taken. At every predetermined time, slides for the comet assay are prepared.
ADME/Pharmacokinetics	Absorption, Distribution and Excretion Peak plasma levels occurred in male dogs between 2 and 4 hours after dosing. Peak plasma levels were approximately 55-65 ug flumequine equivalents/mL of plasma after an oral dose of 25 mg/kg bw. Approximately one-half the concentration of total radioactivity for the first 12 hours following administration corresponded to unchanged drug. The disappearance of flumequine from the plasma appeared to follow multi-exponential kinetics with an initial half-life of about 75 minutes and a terminal beta-phase half-life of 6.5 hours. Studies with (14)C-flumequine in dogs and rats indicated that flumequine is readily absorbed following oral administration. There was a significant difference in the mode of drug excretion between dogs and rats. In dogs, 55-75% of the dose was excreted in the faeces compared to only 10-15% in rats. Less than 5% of the dose was present in the urine of dogs as unchanged drug while another 13-15% was excreted as a conjugate of flumequine. In rats, 20-36% of the dose was excreted in urine as unchanged drug and very little as a conjugate of flumequine. The concentrations of free flumequine in the 24-hour urine sample were about the same for both species. Total recovery of the orally administered dose was achieved in the urine and feces within 5 days after dosing in both species /rats and dogs/, indicating that very little residual flumequine and/or metabolites were retained in the tissues. For more Absorption, Distribution and Excretion (Complete) data for FLUMEQUINE (8 total), please visit the HSDB record page. Metabolism / Metabolites In dogs, less than 5% of the dose was excreted in the urine as unchanged drug and 13-15% was excreted as an acid-labile urinary conjugate of flumequine (or a material fluorometrically similar to flumequine). In rats, 20-36% was excreted in the urine as unchanged drug and very little as an acid-labile conjugate. In a 13-week study designed to investigate hepatotoxic lesions and the activities of hepatic drug-metabolizing enzymes, flumequine was administered to male CD-1 mice in the feed at doses equal to 0, 25, 50, 100, 400, or 800 mg/kg bw per day and to females at 0, 100, 400, or 800 mg/kg bw per day. ... Flumequine caused little or no induction of hepatic cytochrome P450-dependent drug-metabolizing enzymes or glucuronyltransferase when given at doses up to 800 mg/kg bw per day. ... To determine the plasma and urine levels of flumequine and its metabolite, 7-hydroxyflumequine, 28 healthy male subjects were given single and multiple oral doses of 400, 800 and 1200 mg flumequine. Results showed mean concentrations at 2 hr of 13.5, 23.8 and 31.9 mg/L, respectively. These levels were sustained up to 6 hr postdose. Following a single 800 mg dose, peak plasma levels of 14-25 mg/L occurred between 2.5 and 3.5 hr. The mean elimination half-life was 7.1 hr. In plasma only minimal levels of 7-hydroxyflumequine were found. Following 800 mg of flumequine four times a day, mean trough plasma levels of unchanged drug ranged from 21-23 mg/L. Mean peak concentrations were 41 mg/L at steady-state. The half-life following the last dose (8.5 hr) was not significantly different from the 7.1 hr half-life following the first dose. Substantial drug levels were present in the urine for 24 hr following single oral doses of 400, 800 and 1200 mg of flumequine. Urine levels of 7-hydroxyflumequine were generally higher than the parent compound. In the multiple dose study, the overnight concentration of flumequine always exceeded 50 mg/L, and the overnight concentration of 7-hydroxyflumequine always exceeded 80 mg/L. Biological Half-Life ... /In rats/ after administration of the 25 mg/kg bw oral dose ... the plasma half-life for flumequine was 5.25 hours. ... /In male dogs/ after an oral dose of 25 mg/kg bw ... the disappearance of flumequine from the plasma appeared to follow multi-exponential kinetics with an initial half-life of about 75 minutes and a terminal beta-phase half-life of 6.5 hours. ... After IV and oral administration /in chickens/ (single-dose of 12 mg flumequine/kg bw ... elimination half-life and mean residence time of flumequine in plasma were 6.91 and 5.90 hr, respectively, after IV administration and 10.32 and 8.95 hr after oral administration. ... To determine the plasma and urine levels of flumequine and its metabolite, 7-hydroxyflumequine, 28 healthy male subjects were given single and multiple oral doses of 400, 800 and 1200 mg flumequine. ... Following a single 800 mg dose, peak plasma levels of 14-25 mg/L occurred between 2.5 and 3.5 hr. The mean elimination half-life was 7.1 hr. ... Following 800 mg of flumequine four times a day ... the half-life following the last dose (8.5 hr) was not significantly different from the 7.1 hr half-life following the first dose.
Toxicity/Toxicokinetics	Toxicity Summary IDENTIFICATION AND USE: Flumequine is a fluoroquinolone compound with antimicrobial activity against Gram-negative organisms. It is used in the treatment of enteric infections in food animals and in the treatment of bacterial infections in farmed fish. Flumequine also has limited use in humans for the treatment of urinary tract infections. HUMAN EXPOSURE AND TOXICITY: Ocular side effects in 3 patients being treated with flumequine for urinary infections were reported. All 3 patients had chronic renal failure and all exhibited bilateral symmetry. Complete recovery occurred within 2 days of withdrawing the drug. ANIMAL STUDIES: Flumequine was administered by gastric tube to female mice for 14 days. No signs of alopecia or other toxicity were noted. Rats were orally administered flumequine for 14 days. Marked alopecia was observed in both sexes after 3 to 5 days treatment, which persisted for the duration of the study. In other study rats were orally administered flumequine for 14 days. Clinical signs included bloating, cyanosis, dehydration, reduced weight gain, and shedding. Guinea pigs were given oral doses of flumequine for 14 days. Mortality was noted. Beagle dogs were given daily oral doses of flumequine. All dogs survived the one-year treatment period. A decrease in food consumption was noted in all treatment groups throughout the study. A dose-dependent incidence of convulsive episodes was observed in treated dogs. The convulsions were relatively severe, of short duration (15-30 seconds), and almost always followed by ataxia and tremors. Normal behavior returned within about ten minutes after treatment. Other drug-related clinical signs observed included ataxia, hypoactivity, tremors, emesis, decreased food consumption, and body-weight loss. In an 18-month study, flumequine was administered in the feed to mice of each sex. A slight depression in body weight occurred in the high-dose group from the sixth week to termination of the study. Incidences of liver tumors seen grossly at necropsy were dose-related and more prevalent in males than in females. The incidence of hepatic toxic changes paralleled the liver tumor incidence. Chi-square analysis of the number of tumor-bearing animals indicated significant increases for the low- and high-dose males considering all tumors and benign tumors. The number of high-dose males with both benign and malignant liver tumors was also statistically significant. In females, the only significant increases occurred in the high-dose group for numbers of animals with any type or benign only tumors. In a 13-week study designed to investigate hepatotoxic lesions and the activities of hepatic drug-metabolizing enzymes, flumequine was administered to mice. The effects observed were reduced body weight, significantly increased plasma activities of alanine and aspartate aminotransferases, alkaline phosphatase and lactic dehydrogenase, and increased liver weights. Pregnant mice were orally administered flumequine from the second to fifteenth days of gestation. Incomplete ossification, invaginated trachea, dilatation of the renal pelvis, and cleft palate were observed in fetuses. These observations were interpreted as evidence of fetotoxic, not teratogenic, responses to exposure to flumequine. Pregnant rats were dosed orally with flumequine from the sixth through fifteenth days of gestation. There was a dose-related reduction of mean body weight in the treated dams and the difference from controls was significant at 400 mg/kg bw/day. The mean fetal weights of the mid- and high-dose groups were significantly lower as compared to controls. Dose-related incomplete ossification of sternebra, vertebrae, and skull bones were also noted in fetuses. No drug-related visceral or skeletal malformations were found and there was no embryotoxic effect noted in this study. Flumequine was negative in the following genotoxicity tests: Ames test, HGPRT test, Gene Mutation Assay and the Chromosome Aberration Assay. Interactions The combined effects of various carcinogens found in food products are a concern for human health. In the present study, the effects of flumequine (FL) on the in vivo mutagenicity of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) in the liver were investigated. Additionally, we attempted to clarify the underlying mechanisms through comprehensive gene analysis using a cDNA microarray. Male gpt delta mice were fed a diet of 0.03 % MeIQx, 0.4 % FL, or 0.03 % MeIQx + 0.4 % FL for 13 weeks. The effects of cotreatment with phenobarbital (PB) were also examined. Treatment with MeIQx alone increased gpt and Spi(-) mutant frequencies, and cotreatment with FL, but not with PB, further exacerbated these effects, despite the lack of in vivo genotoxicity in mice treated with FL alone. FL caused an increase in Cyp1a2 mRNA levels and a decrease in Ugt1b1 mRNA levels, suggesting that the enhancing effects of FL may be due in part to modification of MeIQx metabolism by FL. Moreover, FL induced an increase in hepatocyte proliferation accompanied by hepatocellular injury. Increases in the mRNA levels of genes encoding cytokines derived from Kupffer cells, such as Il1b and Tnf, and cell cycle-related genes, such as Ccnd1 and Ccne1, suggested that FL treatment increases compensatory cell proliferation. Thus, the present study clearly demonstrated the combined effects of 2 different types of carcinogens known as contaminants in foods. Non-Human Toxicity Values LD50 Dog iv >120 mg/kg body weight LD50 Rabbit oral >2000 mg/kg body weight LD50 Mouse (female) iv 822 (718-944) mg/kg body weight LD50 Mouse (female) iv 90 (86-93) mg/kg body weight For more Non-Human Toxicity Values (Complete) data for FLUMEQUINE (12 total), please visit the HSDB record page.
References	[1]. Toxicol Sci . 2002 Oct;69(2):317-21. [2]. J Med Microbiol . 2004 Sep;53(Pt 9):895-901. [3]. Antimicrob Agents Chemother . 1995 May;39(5):1059-64. [4]. Chemosphere . 2000 Apr;40(7):741-50. [5]. J Vet Pharmacol Ther . 2000 Jun;23(3):163-8.
Additional Infomation	9-fluoro-5-methyl-1-oxo-6,7-dihydro-1H,5H-pyrido[3,2,1-ij]quinoline-2-carboxylic acid is a member of the class of pyridoquinolines that is 1-oxo-6,7-dihydro-1H,5H-pyrido[3,2,1-ij]quinoline carrying additional carboxy, methyl and fluoro substituents at positions 2, 5 and 9 respectively. It is a pyridoquinoline, a 3-oxo monocarboxylic acid, an organofluorine compound and a quinolone antibiotic. Flumequine is a synthetic chemotherapeutic antibiotic of the fluoroquinolone drug class used to treat bacterial infections. Therapeutic Uses Anti-Infective Agents, Urinary; Topoisomerase II Inhibitors Flumequine is a fluoroquinolone compound with antimicrobial activity against Gram-negative organisms. It is used in the treatment of enteric infections in food animals and in the treatment of bacterial infections in farmed fish. Flumequine also has limited use in humans for the treatment of urinary tract infections. Drug Warnings The efficacy and safety of flumequine were evaluated in the treatment of 121 cases uncomplicated (65.5%) and complicated (34.5%) urinary tract infections (UTI) when given as a dose of 400 mg bd. Duration of treatment ranged from 7-15 days, with a mean of 10. Thirty days post-therapy, cure persisted in 92.3% of the patients with uncomplicated UTI and in 53.7% of those with complicated UTI. Relapse or re-infection occurred in 34.1% of the patients with complicated UTI, and in 12.2%, the infecting organism did not respond to treatment. Flumequine was generally well tolerated. In 27.3% of patients gastrointestinal, and neurological disorders and skin rashes developed which in most cases were mild. Only two patients were withdrawn from the treatment. It is concluded that flumequine, administered at 800 mg daily, is highly effective in treating uncomplicated and complicated UTI.

Solubility Data

Solubility (In Vitro)

DMSO: 3~7.7 mg/mL (~11.5~29.4 mM) Water: <1 mg/mL Ethanol: <1 mg/mL

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	3.8278 mL	19.1388 mL	38.2775 mL
	5 mM	0.7656 mL	3.8278 mL	7.6555 mL
	10 mM	0.3828 mL	1.9139 mL	3.8278 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.