Sanfetrinem cilexetil (formerly known as GV 118819), a beta-lactam antibiotic, is the oral prodrug of sanfetrinem. Experiments on rodents have revealed that sanfetrinem cilexetil had strong antibacterial activity in vitro and good pharmacokinetic behavior in mice. This drug was suitable for the treatment of infections caused by a variety of bacteria and participated in a phase II clinical trial. However, this study was discontinued.

Thiphencillin is a penicillin analog patented by Abbott Laboratories as an antibacterial agent. Thiphencillin shows potent antibacterial activity against various species and genera of pathogenic bacteria.

Oximonam (also known as SQ 82,291) was developed as a monobactam antibiotic that had shown good activity against different bacteria of the family Enterobacteriaceae and Haemophilus influenzae and was no activity at all against staphylococci and against Pseudomonas aeruginosa.

Sanfetrinem cilexetil (formerly known as GV 118819), a beta-lactam antibiotic, is the oral prodrug of sanfetrinem. Experiments on rodents have revealed that sanfetrinem cilexetil had strong antibacterial activity in vitro and good pharmacokinetic behavior in mice. This drug was suitable for the treatment of infections caused by a variety of bacteria and participated in a phase II clinical trial. However, this study was discontinued.

Amifloxacin [WIN 49375] is a fluoroquinolone antibacterial with a broad range of activity against aerobic Gram-negative and some aerobic Gram-positive organisms. Amifloxacin is a DNA gyrase inhibitor. The 50% inhibiory concentration for supercoiling activity of E.coli KL16 DNA gyrase of amifloxacin (MIC, 0.10 ug/ml) was 2.47 ug/ml. Amifloxacin was in trials for the treatment of gram-negative infections, septic shock and urinary tract infections. However, development of amifloxacin has been discontinued.

Rosamaricin is a macrolide antibiotic similar to erythromycin. This compound is more effective against Gram-negative bacteria than erythromycin, especially in the prostate where rosamaricin was shown to be more concentrated than erythromycin in dogs. Rosamaricin has antibiotic activity against Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis. When the drug was compared with penicillin G in the treatment of pneumococcal meningitis in rabbits it was found to be less effective than penicillin G, as measured by bacterial clearance from cerebrospinal fluid and by treatment outcome. No information on the current use of this compound is available.

Pirbenicillin is a broad-spectrum semisynthetic penicillin with activity against both gram-positive cocci and gram-negative bacilli. Pirbenicillin is less active than either carbenicillin or ticarcillin against Proteus spp. It is as active as carbenicillin against Serratia spp. and Enterobacter spp. Pirbenicillin demonstrated eight- and fourfold better minimal bactericidal concentration values towards Pseudomonas isolates than those of carbenicillin and ticarcillin, respectively. Pirbenicillin binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. The drug is somewhat more stable in serum than carbenicillin. Pirbenicillin does not appear to inactivate gentamicin as rapidly as carbenicillin.

Cefazaflur (INN) is a semisynthetic first-generation cephalosporin antibiotic patented by Smithkline Corp. For treatment of bacterial infections.

Rosamaricin is a macrolide antibiotic similar to erythromycin. This compound is more effective against Gram-negative bacteria than erythromycin, especially in the prostate where rosamaricin was shown to be more concentrated than erythromycin in dogs. Rosamaricin has antibiotic activity against Neisseria gonorrhoeae, Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis. When the drug was compared with penicillin G in the treatment of pneumococcal meningitis in rabbits it was found to be less effective than penicillin G, as measured by bacterial clearance from cerebrospinal fluid and by treatment outcome. No information on the current use of this compound is available.

Trospectomycin is an aminocyclitol antibiotic similar in structure to spectinomycin. The drug was originally developed by Pharmacia & Upjohn. It is a 6'-propyl analogue of spectinomycin, and lacks the aminosugars in glycosidic linkage which are thought to be responsible for the ototoxicity and nephrotoxicity associated with the aminoglycosides. The mechanism of action of trospectomycin is similar to that of its parent compound, spectinomycin: it binds to the bacterial 30S ribosome and inhibits protein synthesis. The transport mechanism for its delivery to its target site does not appear to be oxygen dependent, and this explains the in-vitro activity of trospectomycin against anaerobic organisms. Trospectomycin has activity against a broad spectrum of pathogenic organisms including Streptococcus, Haemophilus, Gardnerella, Neisseria, Peptococcus, Peptostreptococcus, Bacteroides, Mobiluncus, Chlamydia, Mycoplasma and Ureaplasma spp. Results of in-vivo testing suggest potential utility in a variety of clinical conditions including non-gonococcal urethritis, chlamydial cervicitis, gonorrhoea, pelvic inflammatory disease, pneumonia, anaerobic infections and meningitis. Trospectomycin progressed to late stage clinical trials for treatment of pelvic inflammatory disease (chlamydia) before being abandoned for commercial reasons as the third generation cephalosporins and second generation macrolides in development and use were judged superior at the time.