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Development of Chronomers tm for narcotic antagonists
National Institute on Drug Abuse Research Monograph Series
|January 1, 1976
Summary
This study developed a bioerodable naltrexone implant for long-term opioid blockade. The CHRONOMER™ matrix delivers naltrexone effectively, blocking morphine
Area of Science:
- Pharmacology
- Biomaterials Science
- Drug Delivery Systems
Background:
- Naltrexone is a narcotic antagonist used to block the effects of opioid drugs.
- Existing delivery systems may not provide sustained release for the required duration.
- Bioerodable matrices offer potential for controlled drug release via surface erosion.
Purpose of the Study:
- To develop a bioerodable, subcutaneously implantable naltrexone delivery system.
- To achieve naltrexone release over 1-6 months at constant and sufficient rates.
- To block the euphoric effects of morphine-based drugs.
Main Methods:
- Formulation of naltrexone within a solid, hydrophilic CHRONOMER™ matrix.
- In vitro kinetic studies to optimize system composition.
- In vivo efficacy testing using the tail-flick test in rats.
- Toxicological and preliminary sterilization studies (60Co irradiation).
Main Results:
- The CHRONOMER™ matrix demonstrated predictable surface erosion in aqueous media.
- Intravenous naltrexone showed dose-dependent antagonism of morphine analgesia (54-89% antagonism).
- Toxicological studies revealed no limiting adverse effects from CHRONOMER™ or its hydrolysis products.
- Sterilization with 2.5 or 5.0 mrads of 60Co irradiation did not adversely affect the system.
Conclusions:
- A bioerodable naltrexone delivery system using a CHRONOMER™ matrix is feasible for long-term subcutaneous implantation.
- The system has the potential to provide sustained naltrexone release for effective opioid blockade.
- Further development is warranted based on promising efficacy, safety, and sterilization data.
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