Preliminary results suggest that a new sublingual buprenorphine wafer may offer higher bioavailability and faster absorption compared with earlier sublingual formulations of the drug for patients treated for acute and chronic pain.
In this open-label 2-way randomized crossover study published in Pain Medicine, 14 healthy participants receiving naltrexone block were randomly assigned to receive 300 μg intravenous (IV) buprenorphine (constant infusion for 5 minutes; n=8), or 800 μg sublingual buprenorphine (2 treatments with a 7-day washout interval between each treatment; n=8).
Blood samples were taken before treatment and at time points ranging from 10 minutes to 48 hours postdose for plasma drug assay.
According to the drug assay results, absolute bioavailability of the sublingual buprenorphine dose was 45.4% (95% CI, 37.8%-54.3%), which is higher than the 35% bioavailability offered by Temgesic, a currently approved sublingual buprenorphine formulation. The time to peak buprenorphine plasma concentration was 60 minutes with sublingual buprenorphine and 10 minutes with the IV treatment; maximum plasma concentration of the drug was 0.74 ng/mL with the sublingual wafer and 2.65 ng/mL after IV administration.
In addition, the half-life was longer with the sublingual formulation (11.2 hours) compared with the IV administration (9.1 hours). Overall, 79% of participants (57% in each group) reported any treatment-emergent adverse effects, which included lymphadenopathy, headache, and migraine.
The main limitation associated with this study was its small number of participants, which precluded the ability to derive conclusive or significant findings related to either treatment regimen.
According to the investigators, the rapid “disintegration of the sublingual wafer and the release of the pharmaceutical active ingredient active into the mucosa” results in a relatively fast absorption of the sublingual buprenorphine formulation.
Disclosure: This study was supported by iX Biopharma Pty Ltd, Australia, manufacturer of sublingual buprenorphine (Bnox).
Lim SCB, Schug S, Krishnarajah J. The pharmacokinetics and local tolerability of a novel sublingual formulation of buprenorphine [published online January 3, 2018]. Pain Med. doi: 10.1093/pm/pnx321