Background
Two phase I studies assessed the pharmacokinetics of buprenorphine, its metabolite norbuprenorphine, and naloxone following administration of buprenorphine/naloxone sublingual tablets in Chinese participants.
Methods
In the first phase I, open-label, single ascending-dose (SAD) study, 82 opioid-naïve volunteers received a single buprenorphine/naloxone dose ranging from 2 mg/0.5 mg to 24 mg/6 mg while under naltrexone block. In a second phase I, open-label, multiple ascending-dose (MAD) study, 27 patients with opioid dependence in withdrawal received buprenorphine/naloxone doses of either 16 mg/4 mg or 24 mg/6 mg for 9 consecutive days. Serial blood samples were collected after a single dose (SAD study) and at steady-state (MAD study). Pharmacokinetic parameters were calculated using non-compartmental analysis. Safety assessments included adverse events monitoring and laboratory tests.
Results
The pharmacokinetic profiles of buprenorphine and naloxone were consistent between single- and multiple-dose studies. Peak plasma concentrations (
C
max
) were reached early for buprenorphine (0.75–1.0 h) and naloxone (0.5 h), supporting rapid absorption. In the SAD study, increases in plasma exposures to buprenorphine and naloxone were less than dose proportional, in line with previous observations in Western populations. Buprenorphine-to-naloxone ratios for
C
max
and area under the curve (AUC) were constant over the dose range investigated and also consistent with Western populations data. Steady state was reached within 7 days of daily dosing, with slight accumulation over repeated doses. No serious adverse events were observed.
Conclusions
The present data suggest that buprenorphine/naloxone pharmacokinetic profiles in Chinese participants are consistent, overall, with those in Western populations, supporting no differences in dosing.
Clinical Trial Registration
The protocols were registered on the official website of the China Food and Drug Administration (CFDA):
http://www.chinadrugtrials.org.cn/
; Registration numbers CTR20132963 (RB-CN-10-0012), CTR20140153 (RB-CN-10-0015)....

Pharmacokinetics of Sublingual Buprenorphine Tablets Following Single and Multiple Doses in Chinese Participants With and Without Opioid Use Disorder

10.1007/s40268-019-0277-9