Free Base vs Hydrochloride Bupe

[dirzted]

Hello,
I hope this warrants a post here, otherwise mods feel free to move to whatever lower rung of forum you prefer. Reason I desired this forum is I wanted as detailed an explanation as possible.

So, I essentially want someone to translate exactly what this means (as found on my generic subutex bottle): "Each sublingual tablet contains 8.64mg buprenorphine HCl equivalent to 8mg of buprenorphine"

I tried googling all this stuff about free base vs Hydrochloric acids on google, but, seeing as chemistry is not my strong suit, I was unable to find out how the statement is to be interpreted. Is the "8mg of bupe" simply denoting the free base? In which case does that imply clinical trials were done with the free base form? If not, why is this relevant enough information to be printed on the bottle itself and not kept in the laboratory? I am curious but confused.

Thanks for your time.

 

[S.J.B.]

The clinical trials were most likely done with the hydrochloride salt (or another salt). It seems odd that they felt the need to denote the freebase equivalent. The only thing that I can think of is that it has something to do with a prescription quota. DEA manufacturing quotas are based on freebase amounts. Being Schedule III, buprenorphine doesn't have an overall manufacturing quota, but perhaps physicians are only allowed to prescribe a certain amount?

 

[Hodor]

Hello,
I hope this warrants a post here, otherwise mods feel free to move to whatever lower rung of forum you prefer. Reason I desired this forum is I wanted as detailed an explanation as possible.

So, I essentially want someone to translate exactly what this means (as found on my generic subutex bottle): "Each sublingual tablet contains 8.64mg buprenorphine HCl equivalent to 8mg of buprenorphine"

I tried googling all this stuff about free base vs Hydrochloric acids on google, but, seeing as chemistry is not my strong suit, I was unable to find out how the statement is to be interpreted. Is the "8mg of bupe" simply denoting the free base? In which case does that imply clinical trials were done with the free base form? If not, why is this relevant enough information to be printed on the bottle itself and not kept in the laboratory? I am curious but confused.

Thanks for your time.

Bottles typically list the weight of the whole salt (ex. buprenorphine hydrochloride), which includes the weight of the freebase + the weight of the acid, as well as the freebase equivalent.

In the event that somebody should at one point market a different salt of buprenorphine (ex. "buprenorphine hydrobromide") or the freebase itself, then you could use the freebase equivalent to compare the two products: for example, 10 mg of buprenorphine HBr would be equivalent to less bupe freebase than 10 mg of buprenorphine HCl, since a molecule of HBr weighs more than twice as much as a molecule of HCl.

In general, many drugs are almost exclusively available as one salt (usually HCl), though there might be situations where a doctor would want to check e.g. how much morphine HCl is equivalent to 10 mg of morphine sulfate.

 

[dirzted]

Bottles typically list the weight of the whole salt (ex. buprenorphine hydrochloride), which includes the weight of the freebase + the weight of the acid, as well as the freebase equivalent.

In the event that somebody should at one point market a different salt of buprenorphine (ex. "buprenorphine hydrobromide") or the freebase itself, then you could use the freebase equivalent to compare the two products: for example, 10 mg of buprenorphine HBr would be equivalent to less bupe freebase than 10 mg of buprenorphine HCl, since a molecule of HBr weighs more than twice as much as a molecule of HCl.

In general, many drugs are almost exclusively available as one salt (usually HCl), though there might be situations where a doctor would want to check e.g. how much morphine HCl is equivalent to 10 mg of morphine sulfate.

Ahhhhh I see, so not an everyday situation perhaps but still interesting to know about.
Thanks for the response.