Hydrolysis of cefamandole nafate to cefamandole in vivo.

The hydrolysis of cefamandole nafate, and the O-formyl ester of cefamandole, to cefamandole was studied in vivo in dogs and normal human subjects. After administration of cefamandole nafate to dogs or humans, the parent compound disappeared rapidly from plasma. Disappearance was slightly faster in dogs (half-life [t1/2], 4--6 min) than in humans (t1/2, 6--9 min). The calculated rate constant for hydrolysis of cefamandole nafate was also higher in dogs than in humans, yielding t1/2 values of 6--7 min and 10--17 min, respectively. The rapid hydrolysis of cefamandole nafate to cefamandole in vivo, combined with the partial hydrolysis of cefamandole nafate in vitro before administration (caused by Na2CO3 in the formulation), resulted in circulating levels of cefamandole nafate lower than those of cefamandole. In humans the disappearance of cefamandole nafate was not significantly altered after administration of large (4.0 g) or multiple (4.0g every 6 hr) doses of cefamandole nafate.

Nephrotoxicity of cephaloridine in newborn rabbits: role of the renal anionic transport system.

The nephrotoxicity of cephaloridine, cefazolin and mercuric chloride was studied in rabbits of various ages. Cephaloridine produced dose-related elevations in serum urea nitrogen, creatinine and renal tubular necrosis in adult and 30-day-old rabbits, only slight changes at 15 days of age and no effect in 5-day-old rabbits. Cefazolin also produced dose-related nephrotoxicity in adult rabbits but no effect in 15-day-old rabbits. Mercuric chloride administration resulted in similar nephrotoxicity in 5-, 15- and 30-day-old rabbits and adults. The development of susceptibility to cephaloridine nephrotoxicity paralleled the maturation of the renal anionic transport system as determined by the accumulation of p-aminohippurate by renal cortical slices in vitro. Substrate stimulation of the anionic transport system by p-aminohippurate or penicillin increased the nephrotoxicity of cephaloridine in between rabbits. The authors concluded that the lack of cephaloridine nephrotoxicity in newborn rabbits is due to the incomplete development of the renal anionic transport system.