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Clinafloxacin (formerly also known as CI-960, PD-127391, AM-1091; CI 960, PD127391, AM1091) is a broad-spectrum and investigational antibiotic of the fluoroquinolone class with promising antibiotic activity against gram-positive, gram-negative, and anaerobic pathogens. It effectively prevents Streptococcus pneumonia from using DNA gyrase and topoisomerase IV. The quinolone carboxylic acid class of broad-spectrum antibiotics is presently being developed for oral and intravenous treatment of serious infections.
Physicochemical Properties
| Molecular Formula | C17H17CLFN3O3 | |
| Molecular Weight | 365.79 | |
| Exact Mass | 365.094 | |
| Elemental Analysis | C, 55.82; H, 4.68; Cl, 9.69; F, 5.19; N, 11.49; O, 13.12 | |
| CAS # | 105956-97-6 | |
| Related CAS # | 105956-99-8 | |
| PubChem CID | 60063 | |
| Appearance | Light yellow to brown solid powder | |
| Density | 1.573 g/cm3 | |
| Boiling Point | 592.3ºC at 760 mmHg | |
| Melting Point | 253-258ºC | |
| Flash Point | 312ºC | |
| Vapour Pressure | 7.14E-15mmHg at 25°C | |
| Index of Refraction | 1.684 | |
| LogP | 3.129 | |
| Hydrogen Bond Donor Count | 2 | |
| Hydrogen Bond Acceptor Count | 7 | |
| Rotatable Bond Count | 3 | |
| Heavy Atom Count | 25 | |
| Complexity | 626 | |
| Defined Atom Stereocenter Count | 0 | |
| SMILES | O=C(C1=CN(C2CC2)C3=C(C=C(F)C(N4CC(N)CC4)=C3Cl)C1=O)O |
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| InChi Key | QGPKADBNRMWEQR-UHFFFAOYSA-N | |
| InChi Code | InChI=1S/C17H17ClFN3O3/c18-13-14-10(5-12(19)15(13)21-4-3-8(20)6-21)16(23)11(17(24)25)7-22(14)9-1-2-9/h5,7-9H,1-4,6,20H2,(H,24,25) | |
| Chemical Name | 7-(3-aminopyrrolidin-1-yl)-8-chloro-1-cyclopropyl-6-fluoro-4-oxoquinoline-3-carboxylic acid | |
| Synonyms |
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| 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 |
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| 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 IV; DNA gyrase | |
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| ln Vivo |
Clinafloxacin susceptible pneumococcal meningitis that is resistant to penicillin responds well to clinafloxacin therapy in the rabbit model. Clinafloxacin produces an initial reduction at 6 hours when used with the CS strain (2349) (Clinafloxacin MIC=0.12 μg/ml) at doses of 10 mg/kg and 20 mg/kg. The final reduction in mean log cfu/ml at 24 hours is 22.30 and 23.83, respectively. Both are bactericidal at this point, but show regrowth at that time. But in this meningitis model in rabbits, even at 20 mg/kg per day, clinafloxacin (MIC=0.5 μg/ml) does not reduce bacterial titers[3]. This is because the CR strain (4371) exhibits this property. |
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| Enzyme Assay | The antibacterial activities and target inhibition of 15 quinolones against grlA and gyrA mutant strains were studied. The strains were obtained from wild-type Staphylococcus aureus MS5935 by selection with norfloxacin and nadifloxacin, respectively. The antibacterial activities of most quinolones against both mutant strains were lower than those against the wild-type strain. The ratios of MICs for the gyrA mutant strain to those for the grlA mutant strain (MIC ratio) varied from 0.125 to 4. The ratios of 50% inhibitory concentrations (IC50s) of quinolones against topoisomerase IV to those against DNA gyrase (IC50 ratios) also varied, from 0.177 to 5.52. A significant correlation between the MIC ratios and the IC50 ratios was observed (r = 0.919; P < 0.001). These results suggest that the antibacterial activities of quinolones against the wild-type strain are involved not only in topoisomerase IV inhibition but also in DNA gyrase inhibition and that the target preference in the wild-type strain can be anticipated by the MIC ratios. Based on the MIC ratios, the quinolones were classified into three categories. Type I quinolones (norfloxacin, enoxacin, fleroxacin, ciprofloxacin, lomefloxacin, trovafloxacin, grepafloxacin, ofloxacin, and levofloxacin) had MIC ratios of <1, type II quinolones (sparfloxacin and nadifloxacin) had MIC ratios of >1, and type III quinolones (gatifloxacin, pazufloxacin, moxifloxacin, and clinafloxacin) had MIC ratios of 1. Type I and type II quinolones seem to prefer topoisomerase IV and DNA gyrase, respectively. Type III quinolones seem to target both enzymes at nearly the same level in bacterial cells (a phenomenon known as the dual-targeting property), and their IC50 ratios were approximately 2[1]. | |
| Animal Protocol | The increasing incidence of ciprofloxacin resistance in Streptococcus pneumoniae may limit the efficacy of the new quinolones in difficult-to-treat infections such as meningitis. The aim of the present study was to determine the efficacy of clinafloxacin alone and in combination with teicoplanin and rifampin in the therapy of ciprofloxacin-susceptible and ciprofloxacin-resistant pneumococcal meningitis in rabbits. When used against a penicillin-resistant ciprofloxacin-susceptible strain (Clinafloxacin MIC 0.12 microg/ml), clinafloxacin at a dose of 20 mg/kg per day b.i.d. decreased bacterial concentration by -5.10 log cfu/ml at 24 hr. Combinations did not improve activity. The same clinafloxacin schedule against a penicillin- and ciprofloxacin-resistant strain (Clinafloxacin MIC 0.5 microg/ml) was totally ineffective. Our data suggest that a moderate decrease in quinolone susceptibility, as indicated by the detection of any degree of ciprofloxacin resistance, may render these antibiotics unsuitable for the management of pneumococcal meningitis[3]. | |
| References |
[1]. Target preference of 15 quinolones against Staphylococcus aureus, based on antibacterial activities and target inhibition.Antimicrob Agents Chemother. 2001 Dec;45(12):3544-7. [2]. DNA Gyrase and Topoisomerase IV Mutations and their effect on Quinolones Resistant Proteus mirabilis among UTIs Patients. Pak J Med Sci. Sep-Oct 2020;36(6):1234-1240. [3]. Experimental study of clinafloxacin alone and in combination in the treatment of ciprofloxacin-susceptible and -resistant pneumococcal meningitis.Microb Drug Resist. 2003;9 Suppl 1:S53-9. |
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| Additional Infomation |
7-(3-amino-1-pyrrolidinyl)-8-chloro-1-cyclopropyl-6-fluoro-4-oxo-3-quinolinecarboxylic acid is a member of quinolines. Clinafloxacin is a fluoroquinolone antibacterial currently under research. It has been proven to present good antibiotic properties. However, its approval and release have been halted due to the presence of serious side effects. |
Solubility Data
| Solubility (In Vitro) |
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| 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 | 2.7338 mL | 13.6690 mL | 27.3381 mL | |
| 5 mM | 0.5468 mL | 2.7338 mL | 5.4676 mL | |
| 10 mM | 0.2734 mL | 1.3669 mL | 2.7338 mL |