Blood levels and tissue concentrations of cefazedone in animals.

In mice, dogs, and rabbits blood and serum levels were evaluated after parenteral application of (6R,7R)-7-(2-[3,5-dichloro-4-oxo-1(4H)-pyridyl]acetamido)-3-([(5-methyl-1,3,4-thiadiazol-2-yl)-thio]methyl)-8-oxo-5-thia-1-aza-bicyclo[4,2,0]oct-2-ene-2-carboxylic acid (cefazedone, Refosporen), cephalothin and cefazolin. In all three animal species cefazedone produced higher and more prolonged serum levels than did cefazolin. Evaluation of serum protein binding in mouse, dog and rabbit serum revealed marked differences between the species. Cefazedone and cefazolin tissue concentrations were evaluated in rabbits. Both antibiotics did not penetrate the CSF or brain tissue. In all other tissues examined (except bone marrow) higher and more prolonged tissue levels were attained with cefazedone than with cefazolin.