Evaluation of the clearance of a sublingual buprenorphine spray in the beagle dog using gamma scintigraphy.
OBJECTIVE
The aim of this study was to evaluate clearance from the buccal cavity and pharmacokinetic profiles of a sublingual spray formulation in the dog, to assist in interpretation of future pharmacokinetic studies.


METHODS
Radiolabelled buprenorphine in a spray formulation (400 microg/100 microl in 30% ethanol) was administered sublingually to four beagle dogs, and the residence in the oral cavity was determined using gamma scintigraphy. Pharmacokinetic sampling was performed to facilitate correlation of location of dose with significant pharmacokinetic events.


RESULTS
Scintigraphic imaging revealed that clearance of the formulation from the oral cavity was rapid, with a mean T 50% clearance of 0.86 +/- 0.46 min, and T 80% clearance of 2.75 +/- 1.52 min. In comparison, absorption of buprenorphine was relatively slow, with a T max of 0.56 +/- 0.13 h. Good buccal absorption despite short residence time can be explained by lipophilicity of buprenorphine enabling rapid sequestration into the oral mucosa, prior to diffusion and absorption directly into systemic circulation.


CONCLUSIONS
This study demonstrated rapid clearance of a sublingual solution from the canine oral cavity, with T 50% similar to results previously reported in man, providing initial confidence in using a conscious dog model to achieve representative residence times for a sublingual solution.
McInnes
Fiona
F
Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow, G4 0NR, UK. fiona.mcinnes@strath.ac.uk
Clear
Nicola
N
James
Gerry
G
Stevens
Howard N E
HN
Vivanco
Unai
U
Humphrey
Michael
M
D000042:Absorption; D000286:Administration, Sublingual; D000336:Aerosols; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D000818:Animals; D002047:Buprenorphine / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D004285:Dogs; D015902:Gamma Cameras; D008297:Male; D009055:Mouth / Q000000981:diagnostic imaging* / Q000378:metabolism*; D009061:Mouth Mucosa / Q000378:metabolism; D011877:Radionuclide Imaging; D015203:Reproducibility of Results
D000336:Aerosols; D000701:Analgesics, Opioid; D002047:Buprenorphine