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.
Answered by The Community. Making the world better, one answer at a time. Yes Naltrexone has been known to test positive for opiates in almost all at-home drug screens. I was baffled when I tested my daughter, until I called her doctor and confirmed that Naltrexone can indeed cause a false-positive.uboxone can test positive for opiates, as it contains buprenorphine, a mixed agonist-antagonist opiate. Suboxone also contains naloxone, an opiate antag onist.