Semisynthetic drugs cephalosporins

It is a parenteral, semisynthetic third generation cephalosporin. It is not metabolised and approximately 90 percent of drug is excreted by the kidney in unchanged form. It is indicated in lower respiratory tract, skin and soft tissue infection, septicaemia, urinary tract infection and gonorrhoea. 

If a drug fails to meet present day standards because of low in vitro potency, metabolic, or chemical instability, poor oral absorption or high degree of serum and tissue binding, experience teaches that the prospects for improvement via structural modification are good—if systematic structural modification with retention of biological activity is feasible. The clinically established semisynthetic cephalosporins, rifamycin SV and rifampicin represent precisely this kind of improvement, while laboratory data indicate that it has also been achieved in the coumermycin series as well (96, 97). 

Here as with the tetracyclines, the solution of difficult chemical problems was a prerequisite to successful new drug discovery. At first the counterpart of 6-aminopenicillanic acid could be made only in very low yields by chemical hydrolysis. A practical enzymatic hydrolysis of cephalosporin C to 7-aminocephalosporanic acid (7-ACA) was not found. R. B. Morin and co-workers provided the elegant solution (Figure 21) (101), which made the preparation of 7-ACA and semisynthetic cephalosporins possible on a practical scale. The impetus to persevere in this... 

Mechanism of Action. The drug has been specifically designed as an orally active semisynthetic cephalosporin. Importantly, there are two vital reasons that are solely responsible for the oral inactivation of cephalosporins, namely ... 

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