[Studied on protein binding of cefadroxil and some other cephalosporins (author's transl)]

1. Human serum protein binding of cefadroxil and some other cephalosporins were determined by centrifugal ultrafiltration (U.F.) method and equilibrium dialysis (E.D.) method. The binding rates of cefadroxil were 28.1% by U.F. method and 3.8% (beta 1*), 11.6% (beta 2*) by E.D. method. 2. Protein binding of cefadroxil with sera of various animal species were also determined by E.D. method. The binding rates were low as well as that with human serum. 3. With two popular calculation formula for E.D. method, binding rate was considered on the alteration of the ratio of V2/V1.