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.
As a result, NB32 (naltrexone 32 mg/day+bupropion 360 mg/day) was chosen as the primary dose for Phase 3 and was evaluated in all four pivotal studies. â¢ Study NB-201 demonstrated the naltrexone 16 mg/bupropion SR 400 mg combination to also be efficacious with somewhat lower nausea rates compared with NB32.t doses up to 300 mg/day, which includes the indication for smoking cessation, the seizure incidence is approximately 0.1% (Dunner et al., 1998). Doses up to 450 mg/day of bupropion IR have a reported seizure incidence of 0.4% (Johnston et al., 1991).