Delafloxacin (CAS registry number 189279-58-1) was described as WQ-3034 by Wakunaga Pharmaceutical Co., Ltd., Osaka & Hiroshima, Japan. It was first licensed in 1999 to Abbott Park, IL, and further developed as ABT-492. Delafloxacin (Baxdela), a fluoroquinolone antibiotic, is currently being developed by Melinta Therapeutics. It is a novel investigational fluoroquinolone in development for the treatment of uncomplicated gonorrhea, and acute bacterial skin and skin structure infections. Delafloxacin shows MICs remarkably low against Gram-positive organisms and anaerobes and similar to those of ciprofloxacin against Gram-negative bacteria. It remains active against most fluoroquinolone-resistant strains, except enterococci. Its potency is further increased in acidic environments (found in many infection sites). Delafloxacin is active on staphylococci growing intracellularly or in biofilms. Delafloxacin is a dual-targeting fluoroquinolone, capable of forming cleavable complexes with DNA and topoisomerase IV or DNA gyrase and of inhibiting the activity of these enzymes in both Gram-positive and Gram-negative bacteria. On Oct 24, 2016, Melinta Therapeutics Submitted Baxdela New Drug Application for hospital-treated skin infections.

LCB01-0371, an oxazolidinone derivative, shows good activity against Gram-positive pathogens, including Staphylococcus aureus. It is also effective against multidrug-resistant tuberculosis and is currently under clinical development.

Gemifloxacin is an oral broad-spectrum quinolone antibacterial agent used in the treatment of acute bacterial exacerbation of chronic bronchitis and mild-to-moderate pneumonia. Gemifloxacin mesylate is marketed under the brand name Factive, indicated for the treatment of bacterial infection caused by susceptible strains such as S. pneumoniae, H. influenzae, H. parainfluenzae, or M. catarrhalis, S. pneumoniae (including multi-drug resistant strains [MDRSP]), M. pneumoniae, C. pneumoniae, or K. pneumoniae. Gemifloxacin has in vitro activity against a wide range of Gram-negative and Grampositive microorganisms. Gemifloxacin is bactericidal with minimum bactericidal concentrations (MBCs) generally within one dilution of the minimum inhibitory concentrations (MICs). Gemifloxacin acts by inhibiting DNA synthesis through the inhibition of both DNA gyrase and topoisomerase IV (TOPO IV), which are essential for bacterial growth. Streptococcus pneumoniae showing mutations in both DNA gyrase and TOPO IV (double mutants) are resistant to most fluoroquinolones. Gemifloxacin has the ability to inhibit both enzyme systems at therapeutically relevant drug levels in S. pneumoniae (dual targeting), and has MIC values that are still in the susceptible range for some of these double mutants.

Sparfloxacin is a synthetic fluoroquinolone broad-spectrum antimicrobial agent in the same class as ofloxacin and norfloxacin. Sparfloxacin has in vitro activity against a wide range of gram-negative and gram-positive microorganisms. Sparfloxacin exerts its antibacterial activity by inhibiting DNA gyrase, a bacterial topoisomerase. DNA gyrase is an essential enzyme which controls DNA topology and assists in DNA replication, repair, deactivation, and transcription. Quinolones differ in chemical structure and mode of action from (beta)-lactam antibiotics. Quinolones may, therefore, be active against bacteria resistant to (beta)-lactam antibiotics. Although cross-resistance has been observed between sparfloxacin and other fluoroquinolones, some microorganisms resistant to other fluoroquinolones may be susceptible to sparfloxacin. In vitro tests show that the combination of sparfloxacin and rifampin is antagonistic against Staphylococcus aureus. The bactericidal action of sparfloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination. Sparfloxacin is used for the treatment of adults with the following infections caused by susceptible strains microorganisms: community-acquired pneumonia (caused by Chlamydia pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, or Streptococcus pneumoniae) and acute bacterial exacerbations of chronic bronchitis (caused by Chlamydia pneumoniae, Enterobacter cloacae, Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis,Staphylococcus aureus, or Streptococcus pneumoniae). Sparfloxacin has trade names Spacin in Bangladesh, Zagam and Zagam Respipac. Zagam is no longer available in the United States.

Clofoctol [2-(2,4-dichlorobenzyl)-4-(tetramethyl-1,1,3,3-butyl)phenol] is a synthetic antibacterial agent with bactericidal activity on various Gram-positive (especially S. pyogenes and S. pneumoniae, but also Corynebacterium spp. and Propionibacterium acnes) and some Gram-negative bacteria (including Haemophilus influenzae, Bordetella spp., Neisseria meningitides, and Neisseria gonorrhea). A peculiar property of clofoctol is the rapidity of the antimicrobial effect, similar to that of antiseptic compounds, which makes the development of resistance less likely. Following rectal administration of clofoctol, absorption is rapid and nearly complete (about 98%), with a good penetration in the lung tissue. Clofoctol is primarily metabolized by hepatic glucuronidation and excreted through the biliary system; renal elimination is negligible. Clofoctol compound has been used mainly in France (under the trade name Octoplus ) and Italy (as Gramplus) for the treatment of mild upper respiratory tract infections, especially in pediatric patients

Flomoxef is a cephamycin antibiotic with a difluoromethylthio-acetamido group at the 7-beta position of the cephem nucleus, commonly used for postoperative prophylaxis. Flomoxef has activity against epidermides, streptococci, propionibacteria, and both methicillin-resistant and -susceptible Staphylococcus aureus. Flomoxef exhibits a broad spectrum of antibacterial activity against G(+), G(-) and even anaerobes such as Staphylococcus sp., Escherichia coli, and Bacteroides sp., and it can be used singly to treat infection caused by aerobes and anaerobes (Mixed infection) effectively. Flomoxef belongs to the cephamycin, so it is very stable against β-lactamase as well as Extended Spectrum β-lactamase (ESBL), a novel resistance induced by Enterobacteriaceae. There is no Oxyimino group in the structure of Flomoxef, so it won’t derive ESBL and it is also effective for the treatment to ESBL infection. No disulfiram-like reaction and less incidence of vitamin K deficiency than that of Latamoxef. Marketed in Japan as FLUMARIN.

Delafloxacin (CAS registry number 189279-58-1) was described as WQ-3034 by Wakunaga Pharmaceutical Co., Ltd., Osaka & Hiroshima, Japan. It was first licensed in 1999 to Abbott Park, IL, and further developed as ABT-492. Delafloxacin (Baxdela), a fluoroquinolone antibiotic, is currently being developed by Melinta Therapeutics. It is a novel investigational fluoroquinolone in development for the treatment of uncomplicated gonorrhea, and acute bacterial skin and skin structure infections. Delafloxacin shows MICs remarkably low against Gram-positive organisms and anaerobes and similar to those of ciprofloxacin against Gram-negative bacteria. It remains active against most fluoroquinolone-resistant strains, except enterococci. Its potency is further increased in acidic environments (found in many infection sites). Delafloxacin is active on staphylococci growing intracellularly or in biofilms. Delafloxacin is a dual-targeting fluoroquinolone, capable of forming cleavable complexes with DNA and topoisomerase IV or DNA gyrase and of inhibiting the activity of these enzymes in both Gram-positive and Gram-negative bacteria. On Oct 24, 2016, Melinta Therapeutics Submitted Baxdela New Drug Application for hospital-treated skin infections.

Gemifloxacin is an oral broad-spectrum quinolone antibacterial agent used in the treatment of acute bacterial exacerbation of chronic bronchitis and mild-to-moderate pneumonia. Gemifloxacin mesylate is marketed under the brand name Factive, indicated for the treatment of bacterial infection caused by susceptible strains such as S. pneumoniae, H. influenzae, H. parainfluenzae, or M. catarrhalis, S. pneumoniae (including multi-drug resistant strains [MDRSP]), M. pneumoniae, C. pneumoniae, or K. pneumoniae. Gemifloxacin has in vitro activity against a wide range of Gram-negative and Grampositive microorganisms. Gemifloxacin is bactericidal with minimum bactericidal concentrations (MBCs) generally within one dilution of the minimum inhibitory concentrations (MICs). Gemifloxacin acts by inhibiting DNA synthesis through the inhibition of both DNA gyrase and topoisomerase IV (TOPO IV), which are essential for bacterial growth. Streptococcus pneumoniae showing mutations in both DNA gyrase and TOPO IV (double mutants) are resistant to most fluoroquinolones. Gemifloxacin has the ability to inhibit both enzyme systems at therapeutically relevant drug levels in S. pneumoniae (dual targeting), and has MIC values that are still in the susceptible range for some of these double mutants.

Sparfloxacin is a synthetic fluoroquinolone broad-spectrum antimicrobial agent in the same class as ofloxacin and norfloxacin. Sparfloxacin has in vitro activity against a wide range of gram-negative and gram-positive microorganisms. Sparfloxacin exerts its antibacterial activity by inhibiting DNA gyrase, a bacterial topoisomerase. DNA gyrase is an essential enzyme which controls DNA topology and assists in DNA replication, repair, deactivation, and transcription. Quinolones differ in chemical structure and mode of action from (beta)-lactam antibiotics. Quinolones may, therefore, be active against bacteria resistant to (beta)-lactam antibiotics. Although cross-resistance has been observed between sparfloxacin and other fluoroquinolones, some microorganisms resistant to other fluoroquinolones may be susceptible to sparfloxacin. In vitro tests show that the combination of sparfloxacin and rifampin is antagonistic against Staphylococcus aureus. The bactericidal action of sparfloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination. Sparfloxacin is used for the treatment of adults with the following infections caused by susceptible strains microorganisms: community-acquired pneumonia (caused by Chlamydia pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, or Streptococcus pneumoniae) and acute bacterial exacerbations of chronic bronchitis (caused by Chlamydia pneumoniae, Enterobacter cloacae, Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis,Staphylococcus aureus, or Streptococcus pneumoniae). Sparfloxacin has trade names Spacin in Bangladesh, Zagam and Zagam Respipac. Zagam is no longer available in the United States.

Flomoxef is a cephamycin antibiotic with a difluoromethylthio-acetamido group at the 7-beta position of the cephem nucleus, commonly used for postoperative prophylaxis. Flomoxef has activity against epidermides, streptococci, propionibacteria, and both methicillin-resistant and -susceptible Staphylococcus aureus. Flomoxef exhibits a broad spectrum of antibacterial activity against G(+), G(-) and even anaerobes such as Staphylococcus sp., Escherichia coli, and Bacteroides sp., and it can be used singly to treat infection caused by aerobes and anaerobes (Mixed infection) effectively. Flomoxef belongs to the cephamycin, so it is very stable against β-lactamase as well as Extended Spectrum β-lactamase (ESBL), a novel resistance induced by Enterobacteriaceae. There is no Oxyimino group in the structure of Flomoxef, so it won’t derive ESBL and it is also effective for the treatment to ESBL infection. No disulfiram-like reaction and less incidence of vitamin K deficiency than that of Latamoxef. Marketed in Japan as FLUMARIN.