Structure-related effect of pH on the bioassay sensitivity of five thiadiazole cephalosporins (a note)

Using the buffered disc agar-diffusion method with Bacillus subtilis as test organism' a direct relationship was found between the pH, incubation temperature and the structure-dependent activity of five thiadiazole cephalosporins. This appears to be related to the ionizable group(s) of the molecules.