On a new cephalosporin derivative, cephalexin (CEX), experimental and clinical studies were performed being compared with cephaloridine (CER) and cephalothin (CET). The results obtained were as, follows.
1. The sensitivity of CEX against
Staphylococcus aureus was slightly lower than other two cephalosporins. On the medium of pH 6.5 MIC values were smaller than on that of pH 7.2. In the case of Gram negative bacilli there was little difference of MIC value among three cephalosporins, but pH of medium gave the same influence on MIC in three drugs.
2. Effects of lysozyme added to CEX were examined on growth curve of several strains of Staphylococcus aureus and results of such treatment to experimental infection in mice were compared with control group, resulting occasionally favorable effects with lysozyme in both instances.
3. In the experimental subcutaneous staphylococcal infection in mice, effects of CEX oral administration for inhibiting abscess formation were compared with CER intramuscular injection, showing comparable results in both groups.
4. The bile level following oral administration to dog reached as high as five times of serum level, and moreover urinary levels rose to twenty to thirty times of it.
5. In the measurement of tissue distribution after oral administration to mice, very high level was obtained only in the kidney, while in other tissues the concentrations were lower than that of serum.
6. Daily urinary excretion rates were high in the serial dosing to human subjects, but fecal concentration was relatively low in general.
7. In summary of clinicla results, each of all four cases with pyelitis and colitis showed good response, further to one case of angina and three of four respiratory tract infections CEX was also effective. However in one patient with aubacute bacterial endocarditis clinical symptoms were persistent, although the number of Streptococci isolated from blood had been reduced gradually. Any side reaction was not observed except one case which complained of anorexia and epigastric fullness.
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