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Kinetics of a naltrexone sustained‐release preparation
Author(s) -
Chiang C N,
Hollister L E,
Kishimoto Akiri,
Barnett G
Publication year - 1984
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1984.243
Subject(s) - naltrexone , pharmacology , chemistry , medicine , opioid , receptor
A biodegradable sustained‐release naltrexone bead preparation containing 70% naltrexone in a physical mixture with a copolymer of 90% lactic acid and 10% glycolic acid was evaluated in three male subjects. Each subject received a 10‐mg iv dose of naltrexone HCl and a 63‐mg dose by subcutaneous implantation of naltrexone beads. Kinetics of naltrexone estimated from the intravenous dose indicated a plasma clearance range of 3.1 to 3.4 l/min and a t½ range of 1.7 to 3.7 hr. After bead implantation, average plasma naltrexone levels were maintained at 0.3 to 0.4 ng/ml and naltrexol levels were at 0.4 to 1.0 ng/ml for a period of approximately 1 mo, during which urine naltrexone and naltrexol levels were about 20 to 30 and 70 to 200 ng/ml. It was estimated that approximately 70% to 77% of the dose was absorbed after bead implantation. There were no serious adverse effects other than tissue irritation in two of the three subjects. Clinical Pharmacology and Therapeutics (1984) 36, 704–708; doi: 10.1038/clpt.1984.243