Centrifugation: When plasma is required, or when not using a serum gel separator tube, follow these instructions: 1  Draw 12 mL of whole blood for each 5 mL of serum or plasma needed. 2  Centrifuge for at least 15 minutes at 2200-2500 RPM. 3  Pipette the serum or plasma into a clean plastic screw-cap vial and attach the label.
Buccal administration; Naloxone; Naltrexone; opioid antagonist; Pharmacokinetics; First-pass metabolism Summary The opioid antagonists naloxone and naltrexone are both known to undergo extensive first-pass metabolism after oral dosing. The buccal route was investigated as a potential alternative to oral administration. Oral and buccal bioavailabilities of naloxone and naltrexone were determined in rats. Less than 1 % of oral naloxone or naltrexone was bioavailable, but buccal administration resulted in approximately 70% bioavailability for each drug.
Naltrexone blocks the effects of narcotic medicines and alcohol. Naltrexone injection is used to treat addiction to alcohol or narcotic drugs. It is also used to prevent narcotic addiction relapse. Naltrexone injection may also be used for purposes not listed in this medication guide.