The pharmacokinetics of orally administered S-carboxymethyl-l-cysteine in the dog, calf and sheep

The aim of this study was to investigate the feasibility of employing S-carboxymethyl-l-cysteine as a treatment of chronic obstructive pulmonary disease in dogs. To this end the pharmacokinetic parameters of orally administered S-carboxymethyl-l-cysteine were determined in the dog, cow and sheep. Six healthy beagle dogs, six endogenous Greek sheep and four Holstein Fresian calves were orally dosed with 10 mg/kg body weight of S-carboxymethyl-l-cysteine. No significant differences in Tmax and T1/2 were reported between the species. However, significantly higher AUC(0–last), 21.56 ± 6.67 μg h ml−1 and AUC(0–∞), 21.63 ± 6.68 μg h ml−1 were seen in the dogs compared to the sheep and calves. The calculated VD was significantly higher in the sheep (10.4 ± 2.7 L kg−1) and the calves (3.8 ± 0.7 L kg−1) compared to the dogs (1.0 ± 0.6 L kg−1). The rank order of increasing CL was sheep (3.4 ± 2.7 L h−1 kg−1) > calves (2.7 ± 0.4 L h−1 kg−1) > dogs (0.5 ± 0.2 L h−1 kg−1). The result for the dogs was significantly lower that the calculated CL for the sheep and calves.All these results indicate that the oral administration of S-carboxymethyl-l-cysteine may be useful during the therapeutic management of chronic obstructive pulmonary disease in dogs.