This pharmacokinetic investigation was based on the determination of serum and urinary levles of
cephacetrile in 50 subjects given single intramuscular or intravenous doses of 0.5 or 1 gm of the
antibiotic; 30 normal subjects, 10 patients with
renal insufficiency, and 10 patients with chronic
nephritis undergoing maintenance haemodialysis were included in this study. In normal subjects, mean serum half-life was 1.09 hours (Ke = 0.6337) after
intramuscular injection of 0.5 gm
cephacetrile, 1.31 hours (Ke = 0.5276) after
intramuscular injection of 1 gm, and 0.89 hours (Ke = 0.7806) after
intravenous injection of 1 gm. Absorption half-life was 0.45 hours after
intramuscular injection of 1 gm
cephacetrile. The urinary elimination of
cephacetrile over the first 6 hours after injection was on the average 72.7% of the administered dose. After
intravenous injection of 1 gm of the
antibiotic, the plasma clearance of
cephacetrile was 407 ml/min., and its renal clearance 313 ml/min. A linear correlation was found between the values of overall elimination rate constant (Ke) and
creatinine clearance in the subjects under investigation (Ke = 0.0080 + 0.0061 ClCr). The established pharmacokinetic characteristics were used to calculate the maintenance and loading doses as well as the intervals between
injections adjusted to
creatinine clearance. These data constitute true dosage schemes adapted to the particular case of each patient according to his kidney function.