Disposition of ibuprofen in nephrectomized dogs

The pharmacokinetics of ibuprofen were studied in four nephrectomized and three normal dogs after administration of 214.3-227.6 mg iv of ibuprofen. Blood samples were collected at various time intervals for up to 10 h and serum concentrations of ibuprofen were assayed by an HPLC method. The elimination of serum ibuprofen followed first-order kinetics, with mean half-lives of 2.51 +/- 1.10 and 2.81 +/- 0.72 h in normal and nephrectomized dogs, respectively. Mean serum clearance of ibuprofen in nephrectomized dogs, 31.0 +/- 5.2 mL/h/kg, was higher than that in normal dogs, 12.2 +/- 8.6 mL/h/kg, (p less than 0.02). The difference may be attributed to the greater volume of distribution for ibuprofen in nephrectomized dogs, 125.2 +/- 39.0 (88.8-160.4) mL/kg as compared with 53.4 +/- 57.8 (26.0-119.9) mL/kg in the normal group (p less than 0.2).