Pharmacokinetics of Naltrexone Following Intravenous and Oral Routes of Administration in Healthy Volunteers
The purpose of the study is to compare the pharmacokinetics of naltrexone following i.v. and oral administration in healthy volunteers, and to assess the bioavailability of naltrexone following oral administration. Moreover, safety is assessed.
|Study Design:||Allocation: Randomized
Endpoint Classification: Pharmacokinetics Study
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||Pharmacokinetics of Naltrexone Hydrochloride (HCl) Following Intravenous (i.v.) and Oral Routes of Administration in Healthy Subjects|
- Evaluate the pharmacokinetics of naltrexone following i.v. and oral routes of administration in healthy volunteers, and to assess the absolute bioavailability of naltrexone following oral administration.
- Assessment of safety. Vital signs, Physical examination, clinical laboratory tests, and electrocardiogram were performed at screening and study termination. Additionally, vital signs were recorded on Days 1 and 2 of both treatment periods.
|Study Start Date:||May 2003|
|Study Completion Date:||June 2003|
Naltrexone blocks the effects of opioid (morphine-like) drugs by competitive binding at the opioid receptors in the brain. Naltrexone does not possess morphine-like properties and exhibits minimal pharmacologic activity. Naltrexone is marketed as an oral tablet. A wide range of oral bioavailability values have been reported for naltrexone. The wide range in oral bioavailability of naltrexone appears to be due to differences in assay specificity and the method of estimation of bioavailability (use of total drug, free drug, or urinary excretion data rather than plasma level). This was a single-center, randomized (study drug assigned by chance), open-label, 2-treatment, 2-period crossover study in healthy volunteers. Healthy volunteers were randomly assigned to 1 of 2 treatment sequences (AB or BA) with a washout period of 6 to 14 days between treatments. The washout period commenced the day of dosing, after drug administration. Blood samples for determination of blood naltrexone levels were collected at scheduled time points from the arm opposite to the 1 selected for naltrexone i.v. administration. Pulse, blood pressure, breathing rate, body temperature were measured at the times listed in the study schema. Healthy volunteers remained at the research facility for blood sample collection periods and were monitored for adverse events throughout the treatment periods.
Treatment A: 1 mg naltrexone HCl administered i.v. over 15 minutes (naltrexone i.v.). Treatment B: 50 mg naltrexone HCl administered orally (naltrexone oral).