Buprenorphine bioavailabilities:
intravenous: 98%-100%
intranasal: 50%
"Studies of buprenorphine bioavailability have also examined the [...] intranasal (bioavailability, 48%)
"The bioavailability of buprenorphine, HCl (BPP) in sheep after nasal administration of two formulations has been studied. 0.9 mg BPP in 150 microl was administered nasally and compared to 0.6 mg i.v. The test solutions were formulated with 30% polyethylene glycol 300 (PEG 300) and 5% dextrose, respectively. The bioavailability for PEG 300 was 70% (S.D.+/-27%, n=6), whereas the bioavailability for 5% dextrose was 89% (S.D.+/-23%, n=6)."
"Mean intranasal bioavailability was 48.2 +/- 8.35% (mean +/- s.e.m.) of the intravenous value"
intramuscular: 68%
"The observed mean intramuscular bioavailability was 68%"
"Studies of buprenorphine bioavailability have also examined the intramuscular (bioavailability, 50%–100%)"
intrarectal: 54%
"bioavailability of the drug was found to be: [... ]intrarectal (54%)..."
"Relative to the 100% bioavailability from the intraarterial route the mean bioavailabilities were [...] intrarectal, 54%..."
sublingual: ~30%
"Buprenorphine is well absorbed sublingually, with 60% to 70% of the bioavailability of intravenous doses"
"Study results indicate that bioavailability of sublingual buprenorphine is approximately 30%"
"Literature on bioavailability of sublingual buprenorphine presents variable numbers ranging from. 19–58% of the administered dose."
"Relative to the 100% bioavailability from the intraarterial route the mean bioavailabilities were [...] sublingual, 13%"
oral: 10%
"the oral bioavailability for buprenorphine is state to be 10%"
"due to extensive first-pass metabolism, buprenorphine has very poor oral bioavailability (10% of the intravenous route) if swallowed"
intrahepatoportal: 49%
intraduodenal: 9.7%