title: Pharmacokinetics of intramuscularly administered ertapenem.
abstract: Ertapenem (INVANZ) is a new once-a-day parental beta-lactam antimicrobial agent that has been shown to be highly effective as a single agent for treatment of various community-acquired and mixed infections. The plasma pharmacokinetics of a 1-g intramuscular (i.m.) dose was compared with those of a 1-g intravenous (i.v.) dose infused over 30 min, the recommended rate of i.v. infusion for comparison, and over 120 min, which more closely mimicked the time course for absorption of the i.m. form. In a three-period crossover study (Part A), 26 healthy subjects received single doses of ertapenem administered i.m., i.v. infused over 30 min, and i.v. infused over 120 min. Blood for ertapenem analysis was collected over 24 h postdose for each treatment. In Part B, these fasted subjects received a 1-g i.m. dose of ertapenem once daily for 7 days. Following a 1-g i.m. dose and a 1-g i.v. dose infused over 120 min, the geometric mean area under the concentration curve from hour 0 to infinity (AUC(0- infinity )) was 541.8 micro g. hr/ml following i.m. administration and 591.4 micro g. hr/ml following a 120-min infusion; the geometric mean ratio was 0.92 with a 90% confidence interval of 0.88 to 0.95. The geometric mean AUC(0- infinity ) was nearly identical when 1-g doses were infused over 30 or 120 min. Although the maximum concentration of drug in serum was somewhat lower following i.m. administration than following i.v. administration, the shape of the plasma concentration profiles was roughly comparable at later time points. Ertapenem did not accumulate after multiple 1-g i.m. daily doses over 7 days. The geometric mean ratio for AUC(0-24) (day 7/day 1) was 0.98 with a 90% confidence interval of 0.94 to 1.02. Thus, the relative bioavailability of the 1-g i.m. dose was 92%. Ertapenem does not accumulate following multiple daily 1-g i.m. doses over 7 days.
authors.affiliation: Merck Research Laboratories, West Point, Pennsylvania 19486, USA. don_musson@merck.com
authors.forename: Donald G
authors.initials: DG
authors.lastname: Musson
authors.forename: Anup
authors.initials: A
authors.lastname: Majumdar
authors.forename: Kimberly
authors.initials: K
authors.lastname: Birk
authors.forename: Sherry
authors.initials: S
authors.lastname: Holland
authors.forename: Peter
authors.initials: P
authors.lastname: Wickersham
authors.forename: Susan X
authors.initials: SX
authors.lastname: Li
authors.forename: Goutam
authors.initials: G
authors.lastname: Mistry
authors.forename: Alison
authors.initials: A
authors.lastname: Fisher
authors.forename: Scott
authors.initials: S
authors.lastname: Waldman
authors.forename: Howard
authors.initials: H
authors.lastname: Greenberg
authors.forename: Paul
authors.initials: P
authors.lastname: Deutsch
authors.forename: J Douglas
authors.initials: JD
authors.lastname: Rogers
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D019540:Area Under Curve; D018592:Cross-Over Studies; D000077727:Ertapenem; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D007769:Lactams; D008297:Male; D008657:Metabolic Clearance Rate; D047090:beta-Lactams
chemical_list: D000900:Anti-Bacterial Agents; D007769:Lactams; D047090:beta-Lactams; D000077727:Ertapenem