Opioids Oxycodone question

[Whosajiggawaaa]

I've always wondered why it says 18 mg oxycodone as 20 mg oxycodone hydrochloride on both the boxes of contins and ir's, are they just blatently giving less than advertised or is there something to the chemistry ?

Thanks

 

[sekio]

Oxycodone hydrochloride is a mixture of oxycodone freebase, and hydrochloric acid. Only the freebase is active though, and that makes up 9/10 by weight oxycodone HCl molecule.

Don't worry about it.

 

[Whosajiggawaaa]

Oxycodone hydrochloride is a mixture of oxycodone freebase, and hydrochloric acid. Only the freebase is active though, and that makes up 9/10 by weight oxycodone HCl molecule.

Don't worry about it.

Cool, thanks. Just like to know I'm getting my money's (my health insurance's lol) worth cos it's absurdly expensive.

 

[tricomb]

It's probably the amount of OC in freebase form, just like my 5mg percs are actually like 4.8mg or 4.1mg I forget.

 

[xxxyyy]

this is common in prescription drugs, not just oxycodone.

 

[Jrhguitarist1]

Yea those drug company's are good at the rounding up...

 

[sekio]

Yea those drug company's are good at the rounding up...

This is not "rounding up" and shouldn't be construed as such. The reasons the "smaller" freebase weight is provided is because the hydrochloric acid in oxycodone HCl is not active, and because dfifferent chemical compounds contain differen proportions of acid in them. That is to say, 20 milligrams of oxycodone freebase is stronger than 20 mg of salt.

Oxycodone freebase MW 315.36
Hydrochloric acid MW 36.46
Oxycodone hydrochloride 351.82
= 89.64% of oxycodone HCl is the freebase, 10.36% is the hydrochloric acid by mass.

This is where you get the figure that a 20mg oxycodone HCl pill contains 17.928 mg of oxycodone freebase.
And in actuality a 5mg Percocet with oxycodone HCl has 4.482mg of oxycodone freebase.

It just happens that most people are talking about salts of drugs when they talk about dosage.

 

[tricomb]

^Yeah, 4.8-and-some-change milligrams per perc, that's the figure I was trying to remember.

Yea those drug company's are good at the rounding up...

sarcasm maybe?