Tilmicosin is a macrolide antibiotic was prepared by chemical modifications of desmycosin, and is used in veterinary. It is recommended for treatment and prevention of pneumonia in cattle, sheep and pigs, associated with Pasteurella haemolytica, P. multocida, Actinobacillus pleuropneumoniae, mycoplasma species and other microorganisms found sensitive to this compound. Tilmicosin belongs to 16-membered ring group of class macrolides. The antimicrobial mechanism seems to be the same for all of the macrolides. They interfere with protein synthesis by reversibly binding to the 50S subunit of the ribosome. They appear to bind at the donor site, thus preventing the translocation necessary to keep the peptide chain growing. The effect is essentially confined to rapidly dividing bacteria and mycoplasmas. Macrolides are regarded as being bacteriostatic but demonstrate bactericidal activity at high concentrations.

Lenampicillin is a prodrug of ampicillin that inhibits bacterial penicillin binding proteins (transpeptidase) and thus is effective against a wide range of bacterial infections. The drug was developed and marketed in Japan (Takacillin, Varacillin), however its current marketing status is unknown and supposed to be discontinued.

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.

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).

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.

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).

Ceftezole sodium is a cephalosporin antibiotic. Ceftezole was found to be a broad-spectrum antibiotic, active in vitro against many species of gram-positive and gram-negative bacteria except Pseudomonas aeruginosa, Serratia marcescens and Proteus vulgaris. Ceftezole sodium is used as an injectable or through an intravenous mode of delivery. The bactericidal activity of ceftezole results from the inhibition of cell wall synthesis via affinity for penicillin-binding proteins (PBPs). The PBPs are transpeptidases which are vital in peptidoglycan biosynthesis. Therefore, their inhibition prevents this vital cell wall component from being properly synthesized. Ceftezole has been shown to exhibit potent alpha-glucosidase inhibitory activity. In in vitro alpha-glucosidase assays, ceftezole was shown to be a reversible, non-competitive inhibitor of yeast alpha-glucosidase with a Ki value of 5.78 x 10(-7) M when the enzyme mixture was pretreated with ceftezole. Ceftezole is used for the treatment of susceptible bacterial infections including septicemia, respiratory, biliary or GU tract, skin and skin structure, endocarditis. Surgical prophylaxis.

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).

Cefpirome is a semisynthetic, broad-spectrum, fourth-generation cephalosporin with antibacterial activity. Cefpirome binds to and inactivates penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. PBPs are enzymes involved in the terminal stages of assembling the bacterial cell wall and in reshaping the cell wall during growth and division. Inactivation of PBPs interferes with the cross-linkage of peptidoglycan chains necessary for bacterial cell wall strength and rigidity. This results in the weakening of the bacterial cell wall and causes cell lysis. Cefpirome is an injectable extended-spectrum or 'fourth generation' cephalosporin. Its antibacterial activity encompasses many of the pathogens involved in hospital-acquired infections such as Enterobacteriaceae, methicillin-susceptible Staphylococcus aureus, coagulase-negative staphylococci and viridans group streptococci. Cefpirome also has in vitro activity against Streptococcus pneumoniae regardless of penicillin susceptibility. It is stable against most plasmid- and chromosome-mediated beta-lactamases, with the exception of the extended-spectrum plasmid-mediated SHV enzymes. Intravenous cefpirome 2g twice daily has shown clinical efficacy comparable to that of ceftazidime 2g 3 times daily in the treatment of hospitalised patients with moderate to severe infections. Clinical response and bacteriological eradication rates were similar in patients with severe pneumonia or septicaemia treated with either cefpirome or ceftazidime. Cefpirome appeared more effective than ceftazidime in the eradication of bacteria in patients with febrile neutropenia in 1 study; however, clinical response rates were similar in the 2 treatment groups. The tolerability of cefpirome appears similar to that of ceftazidime and other third generation cephalosporins, diarrhoea being the most frequently observed event. Thus, cefpirome is likely to be a valuable extended-spectrum agent for the treatment of severe infections. Cefpirome offers improved coverage against some Gram-positive pathogens and Enterobacteriaceae producing class I beta-lactamases compared with the third generation cephalosporins, although this has yet to be demonstrated in clinical trials.

Cefodizime is a third-generation cephalosporin with a broad spectrum of antibacterial activity. Administered intravenously or intramuscularly 1 to 4 g of cefodizime daily for an average of 7 to 10 days produces a clinical cure in 80 to 100% of patients (adults, elderly or children) with upper or lower respiratory tract infections or urinary tract infections. In comparative trials cefodizime was as effective as other third generation cephalosporins. A single dose of cefodizime (1 or 2 g) is also useful in treating lower urinary tract infections. Urogenital gonorrhoea, whether caused by beta-lactamase producing or non-beta-lactamase producing Neisseria gonorrhoeae, is very effectively treated by single dose therapy with intramuscular cefodizime. Preliminary data from a small number of patients indicates that cefodizime may also be useful in the treatment of otitis media, sinusitis and gynaecological infections, and for the prophylaxis or treatment of surgical infections. The clinical efficacy of cefodizime compared to other third generation cephalosporins is superior to that predicted from in vitro results. This superior activity of cefodizime may be related to the relatively long elimination half-life of the drug or its ability to modify some functions of the immune system--a potentially important finding awaiting further investigation. Cefodizime is well tolerated and has a tolerability profile similar to other members of its class with systemic adverse events being primarily gastrointestinal or dermatological. Cefodizime may be more convenient to administer than some other agents of its class as it may be given once or twice daily. While there are no trials comparing cefodizime to other third generation cephalosporins in immunosuppressed populations, preliminary information indicates cefodizime may be useful in this group. Cefodizime targets penicillin-binding proteins (PBPs) 1A/B, 2, and 3 resulting in the eventual death of the bacterial cell. In vivo experimental models of infection showed that bacterial clearance by this drug is at least as effective compared with other 3rd generation cephalosporins. It has a similar adverse effect profile to other 3rd generation cephalosporins which is mainly being limited to gastrointestinal or dermatological side effects. It is not currently approved by the FDA for use in the United States.