Fentanyl buccal absorption increases with pH

[manoso]

I was doing some research on fentanyl for a friend of mine who ran out of breakthrough meds and was going to chew one of his plastic (non-gel, the kind with the glue on the back side) patches to control BT pain. I discovered this interesting study on dogs showing a marked increase in absorption and bioavailability via the buccal route with an increase in pH in the mouth. Pretty sweet. I'm going to ask him to try this with some baking soda and report back.

http://www.ncbi.nlm.nih.gov/pubmed/7879944

 

[sekio]

This makes sense, typically e.g. nicotine, cocaine, arecoline and other amine drugs are much more completely and rapidly absorbed in alkaline environments (c.f. chewing betel/coca with lime (calcium hydroxide))

 

[nuke]

Yep, these results are as expected. With higher pH values, the equilibrium for amines is driven towards the freebase (deprotonated) form. The deprotonated form of these amines much more readily enters through cellular membranes, facilitating drug absorption.

 

[sekio]

I seem to recall there was a study comparing rectal morphine at pH 5 vs 7, and noting that absorption was retarded at the lower pH, too - so it's not just oral absorption.
http://www.ncbi.nlm.nih.gov/pubmed/4054201

 

[ebola?]

what range of pHs do you think a human ass can comfortably tolerate?

ebola