Pharmacokinetic properties of fentanyl effervescent buccal tablets: a phase I, open-label, crossover study of single-dose 100, 200, 400, and 800 microg in healthy adult volunteers

Abstract

Background: The fentanyl effervescent buccal tablet (FEBT) is designed to enhance the rate and extent of the absorption of fentanyl, an opioid, through the buccal mucosa.

Objectives: The purposes of this study were to assess the dose proportionality of FEBT in healthy volunteers over the potential therapeutic dose range (100-800 microg) and characterize the pharmacokinetic (PK) profile of 4 doses (100, 200, 400, and 800 microg) of FEBT.

Methods: This Phase I, randomized, open-label, 4-period crossover study was conducted at Radiant Research, Honolulu, Hawaii. Healthy adult volunteers with intolerance to opioids were randomly assigned to receive 1 of 4 single-dose sequences of FEBT: 100, 200, 400, and 800 microg (selected to encompass the anticipated therapeutic dose range), with each successive administration separated by a washout period of >or=7 days. Naltrexone hydrochloride (50-mg tablet) was administered-15 and 3 hours before and 9 hours after FEBT administration to block opioid receptor-mediated effects of fentanyl. Plasma fentanyl concentrations were measured from venous samples obtained over 72 hours after FEBT administration. Early fentanyl exposure was assessed using AUC from time 0 to 0.75 hour (the median T(max) of the reference dose [100 microg]) (AUC(0-Tmax')). Adverse events (AEs) were monitored and recorded throughout the study by medically qualified personnel.

Results: Thirty-two subjects (26 men, 6 women; mean [SD] age, 29.3 [7.2] years [range, 19-44 years]; mean [SD] weight, 74.7 [10.7] kg) were enrolled. Median T was between 35 and 45 minutes after FEBT administration. AUC(0-infinity) and C(max) increased approximately linearly with increasing doses of FEBT. Mean plasma fentanyl concentrations decreased from C(max) in a biexponential manner at the 100- and 200-microg doses and decreased in a triexponential manner at the 800-mug dose. Despite the triexponential decrease in the mean profile observed with the 400-microg dose, a biexponential decrease was observed in approximately half of the individual profiles. AUC(0-Tmax') ranged from 0.09 ng x h/mL with the 100-microg dose to 0.52 ng x h/mL with the 800-microg dose. The most commonly reported AEs in the 100-, 200-, 400-, and 800-microg dose groups were as follows: application-site erythema, 3, 3, 4, and 3 subjects, respectively; nausea, 3, 2, 5, and 4 subjects; somnolence, 3, 2, 3, and 2 subjects; and headache, 3, 2, 1, and 4 subjects. None of the AEs were serious.

Conclusions: In this study of the dose proportionality of FEBT in healthy volunteers, the PK profile of FEBT was characterized by a high early systemic exposure of fentanyl (0.09-0.52 ng x h/mL). Dose-dependent parameters (C(max) and AUC) increased in an approximately dose-proportional manner from 100 to 800 microg FEBT.