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In vitro and in vivo evaluation of MDL 19,592, an oral cephalosporin
Abstract:
MDL 19,592 is a new semisynthetic cephalosporin with a good therapeutic potential against Gram-positive bacterial infections when administered orally or parenterally. In the oral treatment of benzylpenicillin-resistant Staphylococcus aureus infections in mice, MDL 19,592 was superior to cephalexin, cephradine, cefaclor, cefadroxil and cefroxadine. These in vivo results reflect the in vitro superiority expressed by MDL 19,592 over the other oral cephalosporins against staphylococci. Additionally, MDL 19,592 orally was superior to cefazolin and cephalothin administered subcutaneously and to a number of penicillinase-resistant penicillins given orally or subcutaneously in the treatment of S. aureus mouse infections. MDL 19,592 killed S. aureus cells at the same or faster rate than did cephalexin or cephradine. As compared to cephalexin, MDL 19,592 was marginally superior in vitro against Streptococcus pyogenes and Streptococcus pneumoniae. In vivo, MDL 19,592 was significantly the more effective of the two against S. pyogenes and marginally more effective against S. pneumoniae. Against Gram-negative organisms, with the exception of Haemophilus influenzae, cephalexin was the more potent of the two antibiotics both in vitro and in vivo. Administered orally to mice, MDL 19,592 was absorbed as rapidly as cephalexin with both drugs attaining similar concentrations in the blood. MDL 19,592, like cephalexin, was minimally bound by mouse serum.
Insights
MDL 19,592, a new semisynthetic cephalosporin, shows strong potential against Gram-positive bacteria like Staphylococcus aureus. It demonstrated superior efficacy in mouse models compared to other oral cephalosporins and penicillins.
Area of Science:
- Microbiology
- Pharmacology
- Infectious Diseases
Background:
- Antibiotic resistance in Gram-positive bacteria poses a significant clinical challenge.
- Semisynthetic cephalosporins are a crucial class of antibiotics for treating bacterial infections.
- Evaluating novel antibiotic candidates is essential for combating evolving pathogens.
Purpose of the Study:
- To assess the therapeutic potential of MDL 19,592 against Gram-positive bacterial infections.
- To compare the efficacy of MDL 19,592 with existing cephalosporins and penicillins in vivo and in vitro.
- To investigate the pharmacokinetic properties of MDL 19,592.
Main Methods:
- In vitro susceptibility testing against Staphylococcus aureus, Streptococcus pyogenes, and Streptococcus pneumoniae.
- In vivo efficacy studies in mouse models of bacterial infections.
- Pharmacokinetic analysis of MDL 19,592 absorption and serum binding.
Main Results:
- MDL 19,592 demonstrated superior oral efficacy against benzylpenicillin-resistant Staphylococcus aureus in mice compared to multiple cephalosporins.
- The new cephalosporin showed comparable or faster killing rates of S. aureus than cephalexin and cephradine.
- MDL 19,592 exhibited marginal in vitro and significant in vivo superiority against Streptococcus pyogenes and Streptococcus pneumoniae compared to cephalexin.
- Against Gram-negative organisms, cephalexin was generally more potent, except for Haemophilus influenzae.
- MDL 19,592 exhibited rapid oral absorption and minimal serum protein binding in mice, similar to cephalexin.
Conclusions:
- MDL 19,592 possesses significant therapeutic potential, particularly against Gram-positive bacterial infections, including resistant strains of Staphylococcus aureus.
- Its efficacy in vivo and favorable pharmacokinetic profile suggest it as a promising candidate for further clinical development.
- MDL 19,592 offers a valuable alternative or addition to the current antibiotic armamentarium for specific Gram-positive infections.