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.

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.

Cefozopran hydrochloride is a third-generation cephalosporin that was launched for the treatment of severe infections in immunocompromised patients caused by staphylococci and enterococci. While it shows a very broad antibacterial spectrum against Gram-positive and Gram-negative organisms, it is particularly potent against S. aureus, Enterococcus faecalis, P. aeruginosa, and Citrobacter freundii. It is resistant to hydrolysis by most chromosomal and plasmid mediated β-lactamases and is reported to be active against respiratory, urinary tract, obstetrical, gynecological, soft tissue, and surgical infections. Similar to β-lactams, cephalosporins interfere with PBP (penicillin binding protein) activity involved in the final phase of peptidoglycan synthesis. PBP’s are enzymes which catalyze a pentaglycine crosslink between alanine and lysine residues providing additional strength to the cell wall. Without a pentaglycine crosslink, the integrity of the cell wall is severely compromised and ultimately leads to cell lysis and death. Resistance to cephalosporins is commonly due to cells containing plasmid encoded β-lactamases.

Temocillin was marketed by Beecham Pharmaceuticals in the UK in the 1980s but achieved little commercial success and was withdrawn, though it remained available via the manufacturer’s medical department. Presently licensed to Eumedica, temocillin is being re-launched in the UK and Belgium for treating UTI, sepsis, and respiratory infections by ESBL (Extended-spectrum beta-lactamases) and AmpC-producing Enterobacteriaceae. It acts by inhibiting the synthesis of the peptidoglycan layer of bacterial cell walls. It irreversibly binds to the active site of specific transpeptidases and carboxypeptidases known as Penicillin Binding Proteins (PBP), preventing peptidoglycan production.

Metampicillin is the approved name for the penicillin resulting from the reaction of ampicillin with formaldehyde. Metampicillin is hydrolysed in aqueous solution with the formation of ampicillin. Metampicillin has broad spectrum of activity coupled with a marked degree of stability to bacterial penicillinase. Furthermore, metampicillin is reported to be absorbed to a greater extent than ampicillin, resulting in superior blood levels in human subjects, and also giving high levels of antibiotic in bile following parenteral administration. Metampicillin showed a spectrum and level of activity similar to that of ampicillin in vitro, and both compounds were inactive against penicillinase-producing strains of bacteria. The activity of metampicillin was markedly reduced by human serum, and the compound was less active than ampicillin in the presence of human serum. Following the oral administration of metampicillin to man, metampicillin was not detected in the blood stream nor in urine, and ampicillin alone was demonstrated in these subjects. The serum concentrations of ampicillin that were produced following the oral administration of metampicillin were somewhat lower than those obtained with equivalent doses of ampicillin. Adminstration of metampicillin by the intramuscular (i.m.) route to volunteers resulted in the appearance of both ampicillin and metampicillin in the blood, and of ampicillin alone in the urine of these subjects. When parenteraly administered, metampicillin appeared to be a particularly suitable penicillin for the treatment of biliary tract infections. Metampicillin is a cell wall biosynthesis inhibitor.

Sulfaperine is a long-acting sulfonamide antibiotic.

Brodimoprim, is a new 2,4-diaminobenzylpyrimidine that , that selectively inhibits bacterial and resistance plasmid dihydrofolate reductases to a similar or greater extent than trimethoprim. Brodimoprim is two to three times more potent than trimethoprim and has more than 100-fold the affinity for dihydrofolate reductase with analogous enzymatic activity of eukaryotic cells. Brodimoprim’s in vitro activity is similar to that of trimethoprim. Brodimoprim is decidedly superior to trimethoprim in vivo in the mouse acute infection model, due to its much longer elimination half-life and better tissue diffusion. Acute and subacute toxicity tests in traditional laboratory animals show that there is little difference between brodimoprim and trimethoprim. Brodimoprim had no teratogenic or embryotoxic effects and mutagenic analysis was negative

Cefminox is a broad-spectrum, bactericidal cephalosporin antibiotic. It is especially effective against Gram-negative and anaerobic bacteria. It is indicated in treatment of the following infections caused by sensitive bacteria: 1. Respiratory infections: Amygdalitis, circumtonsillar abscess, bronchitis, bronchiolitis, bronchiectasis (in fection), secondary infections of chronic respiratory diseases, pneumonia, and pulmonary suppuration; 2. Infection in urinary system: Nephropyelitis, cystitis; 3. Infections in abdominal cavity: Cholecystitis' angiocholitis'peritonitis; 4. Infections in pelvic cavity: Pelvic peritonitis, adnexitis, intrauterine infection, inflammation in pelvic dead space, and parametritis; 5. Septicaemia.

Cefetamet pivoxil is an oral third-generation cephalosporin which is hydrolysed to form the active agent, cefetamet. Cefetamet has excellent in vitro activity against the major respiratory pathogens Streptococcus pneumoniae, Haemophilus influenzae, Moraxella (Branhamella) catarrhalis and group A beta-haemolytic streptococci; it is active against beta-lactamase-producing strains of H. influenzae and M. catarrhalis, but has poor activity against penicillin-resistant S. pneumoniae. Cefetamet has marked activity against Neisseria gonorrhoeae and possesses a broad spectrum of activity against Enterobacteriaceae. Both staphylococci and Pseudomonas spp. are resistant to cefetamet. Cefetamet pivoxil has been investigated in the treatment of both upper and lower community-acquired respiratory tract infections and has demonstrated equivalent efficacy to a number of more established agents, namely cefaclor, amoxicillin and cefixime. In complicated urinary tract infections, cefetamet pivoxil showed similar efficacy to cefadroxil, cefaclor and cefuroxime axetil. Cefetamet pivoxil was effective in the treatment of otitis media, pneumonia, pharyngotonsillitis and urinary tract infections in children. Cefetamet is not extensively bound to plasma proteins. Cefetamet has a relatively small apparent volume of distribution consistent with that of other beta-lactam antibiotics. The absorption and disposition of cefetamet in human subpopulations [i.e. children, elderly (< 75 years of age), renal impairment, liver disease and patients taking concomitant drugs] have been studied extensively. Only impaired renal function appears to significantly alter the elimination of this drug. Cefetamet pivoxil exerts its bactericidal action by inhibition the final transpeptidation step of peptidoglycan synthesis in the bacterial cell wall by binding to one or more of the Penicillin-binding Proteins (PBPs).