Rosoxacin (0.03-8 µg/mL; 24 h) has good sensitivity to 32 species of Neisseria gonorrhoeae, with a MIC range of 0.03-0.125 µg/mL[1]. Rosoxacin (0.03-8 µg/mL; 48 h) has antibacterial activity against Chlamydia trachomatis (11 strains) with a MIC of 5 µg/mL [1]. Rosoxacin (0.03-8 µg/mL; 6 days) has antibacterial activity against Ureaplasma urealyticum (7 strains) with a MIC range of 2-8 µg/mL [1].

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Rosoxacin demonstrated high activity against 32 clinical isolates of Neisseria gonorrhoeae by agar dilution method. The minimal inhibitory concentration (MIC) for 50% of isolates was 0.03 μg/ml, and over 90% of strains were inhibited by 0.06 μg/ml. For comparison, MIC50 values of other drugs were: amoxicillin 0.125 μg/ml, ampicillin 0.125 μg/ml, erythromycin 0.25 μg/ml, tetracycline 0.25 μg/ml, penicillin G 0.25 U/ml, and spectinomycin 16 μg/ml. MIC90 values were: rosoxacin 0.06 μg/ml, amoxicillin and ampicillin 0.25 μg/ml, erythromycin and tetracycline 1.0 μg/ml, penicillin G 1.0 U/ml, and spectinomycin 16 μg/ml. [1]
Against 30 strains of Chlamydia trachomatis, the first 19 strains tested were resistant to rosoxacin at concentrations up to 1.0 μg/ml. The subsequent 11 strains all had MICs of 5.0 μg/ml. Erythromycin inhibited 97% of C. trachomatis strains at 0.5 μg/ml or less. [1]
Against seven Ureaplasma urealyticum strains from urine sediments, the initial MIC of rosoxacin ranged from 2 to 8 μg/ml (median 2 μg/ml), and the final MIC ranged from 2 to >8 μg/ml (median 4 μg/ml). Six of seven isolates showed equal initial MICs, and final MICs varied by only two dilutions. [1]

Cell viability assay [1]
Cell Types: Neisseria gonorrhoeae (32 strains)
Tested Concentrations: 0.03-8 µg/mL
Incubation Duration: 24 hrs (hours)
Experimental Results: demonstrated good anti-gonococcal activity. Neisseria gonorrhoeae, 50% (32 strains) of the strains had an MIC of 0.03 µg/mL, and 90% of the strains had an MIC of 0.06 µg/mL. Cell viability determination [1]
Cell Types: Chlamydia trachomatis (11 strains)
Tested Concentrations: 0.03-8 µg/mL
Incubation Duration: 48 h
Experimental Results: 11 strains of Chlamydia trachomatis were inhibited, and the MIC was 5 µg/mL.

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Cell viability assay [1]
Cell Types: Ureaplasma urealyticum (7 strains)
Tested Concentrations: 0.03-8 µg/mL
Incubation Duration: 6 days
Experimental Results: Inhibited 7 strains of Ureaplasma urealyticum, MIC range was 2-8 µg/mL.

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For Chlamydia trachomatis susceptibility testing, McCoy cell monolayers were infected with 100 to 200 inclusion-forming units per coverslip prepared by dilution in antibiotic-free culture medium. The cell culture vials were centrifuged, and the medium was removed and replaced with fresh medium containing the test antibacterial drug. Each concentration of antibacterial drug was tested in four cell culture vials. After 48 hours of incubation, the cell cultures were stained with iodine to identify chlamydial inclusion bodies. The minimal inhibitory concentration (MIC) was read as the lowest concentration of antibacterial drug preventing the appearance of any inclusion bodies in the cell monolayer. [1]

In initial oral dose-ranging studies in human volunteers, administration of 250 mg of rosoxacin produced peak serum levels of 6.4 μg/ml after 2 hours. Even after 8 hours, the serum level exceeded 2.9 μg/ml, and after 24 hours the serum level was 0.34 μg/ml. [1]
In dog studies (cited from reference), relatively high drug concentrations were found in prostatic, urethral, and vaginal tissues. [1]

[1]. Dobson RA, et al. In vitro antimicrobial activity of rosoxacin against Neisseria gonorrhoeae, Chlamydia trachomatis, and Ureaplasma urealyticum. Antimicrob Agents Chemother. 1980 Nov;18(5):738-40.

Rosoxacin is a quinolone monocarboxylic acid with the structure 1,4-dihydroquinolone-3-carboxylic acid, substituted with an ethyl group at position 1 and a pyridin-4-yl group at position 7. It is an antibacterial drug effective against Neisseria gonorrhoeae and has been used to treat urinary tract infections and certain sexually transmitted diseases. It is both an antibacterial and anti-infective agent. Rosoxacin belongs to the quinolone antibiotic class, quinolone monocarboxylic acid class, and pyridine class of compounds. Rosoxacin is a quinolone derivative antibiotic used to treat bacterial infections of the respiratory tract, urinary tract, gastrointestinal tract, central nervous system, and in immunocompromised patients. Rosoxacin is effective against penicillin-resistant strains and is a single-dose oral medication, avoiding all the complications of parenteral penicillin administration, especially anaphylactic shock.

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Drug Indications
For the treatment of bacterial infections of the respiratory tract, urinary tract, gastrointestinal tract, central nervous system, and in immunocompromised patients.
Mechanism of Action Rosoxacin binds to and inhibits the activity of topoisomerase II (DNA gyrase) and topoisomerase IV, both of which are essential for bacterial DNA replication, transcription, repair, and recombination. Pharmacodynamics Rosoxacin is a non-fluoroquinolone antibiotic. Its mechanism of action is to block bacterial DNA replication by binding to DNA gyrase, thereby preventing the unwinding of the DNA double helix and allowing one DNA double helix to replicate into two. Rosoxacin is a broad-spectrum antibiotic effective against both Gram-positive and Gram-negative bacteria.

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Rosoxacin has the chemical structure shown in Figure 1 (1-ethyl-1,4-dihydro-4-oxo-7-(4-pyridinyl)-3-quinolinecarboxylic acid). The high serum levels achieved in humans relative to the very low MICs against penicillin-susceptible N. gonorrhoeae indicate potential usefulness in treating gonorrhea, supported by an initial clinical trial (Limson et al., 1979). The in vitro susceptibility of Chlamydia (MIC ~5 μg/ml) and Ureaplasma (MIC ~2-8 μg/ml) to rosoxacin, coupled with serum concentrations and tissue distribution expected from multiple doses, suggests it may be possible to treat infections with these organisms using acceptable doses of rosoxacin. [1]

C17H14N2O3

294.3047

294.1

40034-42-2

287180

Typically exists as solid at room temperature

1.317g/cm3

500.8ºC at 760 mmHg

290°

256.7ºC

1.633

2.781

1

5

3

22

482

0

O=C1C(C(=O)O[H])=C([H])N(C([H])([H])C([H])([H])[H])C2C([H])=C(C3C([H])=C([H])N=C([H])C=3[H])C([H])=C([H])C=21

XBPZXDSZHPDXQU-UHFFFAOYSA-N

InChI=1S/C17H14N2O3/c1-2-19-10-14(17(21)22)16(20)13-4-3-12(9-15(13)19)11-5-7-18-8-6-11/h3-10H,2H2,1H3,(H,21,22)

1-ethyl-4-oxo-7-pyridin-4-ylquinoline-3-carboxylic 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)

DMSO : ~20.83 mg/mL (~70.78 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (7.07 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 (7.07 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.)