Garenoxacin is an antibacterial agent active against a range of aerobic Gram-positive and Gram-negative bacteria. It exerts its action by inhibiting bacterial DNA gyrase and topoisomerase IV. The drug was withdrawn from the market in Europe and was never approved in the USA. Garenoxacin is still marketed in Japan under the name Geninax.

Bacmecillinam is the orally active 1’-ethoxycarbonyloxyethyl ester of macillinam. It is rapidly absorbed and hydrolyzed, liberating the antibacterially active drug mecillinam. Protective effects of bacmecillinam was tested in experimental mouse intraperitoneal infection model. Drug demonstrated the potent protective effects against E. coli GN 2411-5, E. coli 2848, K. pneumoniae 8045, E. cloacae F-1510 and P. mirabilis F-783 infection.

Rokitamycin is a macrolide antibiotic against Gram-positive bacteria. Synthesized from strains of Streptomyces kitasatoensis. Rokitamycin is an inhibitor of protein synthesis by specifically binding to the 50 S subunit of the ribosome. Specificity towards prokaryotes relies upon the absence of 50S ribosomes in eukaryotes.

Iclaprim is an investigational broad-spectrum diaminopyrimidine antibiotic in development for the treatment of acute bacterial skin and skin structure infections (ABSSSIs). Iclaprim acts on bacterial cells by competitively inhibiting dihydrofolate reductase (DHFR), a key enzyme in the folate cycle; the same mode of inhibition is exerted by trimethoprim. Iclaprim resistance is mainly determined by point mutations in the dfr gene as studied in S. aureus and S. pneumoniae. Surveillance studies demonstrate that the spectrum of activity of iclaprim includes many organisms indicated in cSSSI including S. aureus and S. pyogenes. Iclaprim is bactericidal in vitro, generally at concentrations equal to the MIC that are maintained in human plasma for several hours after a therapeutic dose. Bactericidal activity is primarily time-dependent and concentration independent. Due to its structural similarity with trimethoprim, iclaprim is synergistic with sulfonamides against a broad spectrum of bacterial species. The antimicrobial mechanism of action of iclaprim is mediated by competitive inhibition of bacterial DHFR, the same mode of inhibition exerted by TMP. The activity of iclaprim against TMP-R mutants of S. aureus and S. pneumoniae is attributable to additional hydrophobic interaction between iclaprim and the enzyme. The same mechanism of action of iclaprim, competitive inhibition with the natural substrate DHF, is seen against both TMP-S and -R enzymes. Iclaprim is well suited for use as a first-line empiric monotherapy in patients with ABSSSI who are comorbid with renal impairment for the following reasons. n July 2015, the U.S. Food and Drug Administration, or FDA, designated the IV formulation of iclaprim as a Qualified Infectious Disease Product (QIDP) for ABSSSI and HABP. QIDP status grants iclaprim regulatory Fast Track designation, Priority Review and, if approved, a five-year extension to the statutory market exclusivity period in the United States, resulting in 10 years of market exclusivity from the date of approval.

Toltrazuril (Baycox, Procox, Tolcox, Toltrazuril) is a veterinary drug approved in Europe for the treatment of parasitic infections caused by roundworms and coccidia. In dogs it is used in combination with emodepside (Procox).

Thiocarlide (or tiocarlide or isoxyl) is a drug which was used in the treatment of tuberculosis. In addition was preclinical experiments, which showed, that it purely bacteriostatic against M. leprae. The precise mechanism is still unknown but was shown, that Delta9-desaturase could be a target for it. The more recent experiments have revealed, that Thiocarlide inhibits the dehydration step by the (3R)-hydroxyacyl dehydratases HadAB and HadBC.

Alafosfalin is a phosphonodipeptide with significant activity as an antibacterial agent and as a potentiator of beta-lactam antibiotics. Alafosfalin shows good activity both in vitro and in vivo, particularly against Enterobacteriaceae. The compound acts by interfering with bacterial cell wall biosynthesis and also potentiates the activity of beta-lactam antibiotics. Alafosfalin was found to be highly active against Escherichia coli and moderately active against Serratia, Klebsiella, Enterobacter, and Citrobacter, but less active against gram-positive organisms than were beta-lactams such as cephazolin or ampicillin and inactive against indole-positive Proteus, Pseudomonas, and Acinetobacter.

Morinamide is a second line anti-tuberculous agent. In vitro morinamide demonstrated clear dose-dependent bacteriostatic and bactericidal activities. The anti-mycobacterial effect of morinamide was the same as pyrazinamide and was dependent on the acidity of medium (pH 5.6). Liver function test abnormalities following morinamide therapy are usually mild, and onset of jaundice is extremely uncommon. It has been given orally as the hydrochloride in the treatment of tuberculosis.

Metyridine has been shown to possess anthelmintic activity, particularly for the nematodes of the alimentary canal. Methyridine is able to pass freely through most of the barriers, which maintain body integrity. It produces neuromuscular block of the decamethonium type. There appears to be sufficient difference between the sensitivity of nematode and vertebrate nervous systems to this drug to allow a wide safety margin for its use in animals. Signs of toxicity, principally dullness and lassitude, may be produced by overdosage of the drug. When given subcutaneously methyridine may cause local pain, and swelling.

Thiamphenicol is a broad-spectrum antibiotic, which is active against gram-positive and gram-negative organisms. The drug is marketed in Asia and Latin America for the treatment of various infections, including sexually transmitted diseases. As many phenicols, thiamphenicol inhibits the protein synthesis in bacterias by binding to 23S ribosomal subunit. In Europe and USA the drug is used in a veterinary practice.