Pharmacology - Why should it be impossible to do a CWE with effervescent tablets?

[kant]

Whenever SWIM looks this up, he can only find overly dramatic warnings "NOT!!!" to do a CWE on effervescent tablets instead of a clear explanation based on scientific reasons. Now, as far as SWIM knows, the solubility of paracetamol in water is very low. Why should it be any higher in soluble tablets? SWIM has always believed that they produce soluble tablets simply for more comfortable use. He imagines that upon dissolving a sufficient amount of effervescent tablets the resulting solution should be no different from one that dissolving regular tablets yields, in terms of filtering required etc.
Please let me know if I am mistaken and why.

[Sushi]

Madlab tried to find an answer to the same question recently.
After digging through a whole host of CWE threads she reached an opposite conclusion that it's quite possible to do it as paracetamol (and codeine) solubility in cold water would be the same and the most troublesome obstacle to the extraction procedure would rather be keeping a churning fluid in a container of choice.
But there's another, apparently more serious problem, posed by inactive ingredients of effervescent tablets, namely salts. All the warnings she read were related to their effect on kidneys but she would really like to know what's the foundation of those fears and what's the (approximate) amount of inactive ingredients in effervescent tablets that can be ingested relatively safely.

Could someone knowledgeable expand on it?

[kant]

This is finally something informative, thanks!

Perhaps the salts can be removed from the solution by filtering through activated carbon. Since it removes caffeine (SWIM can confirm this from experience) and any remaining paracetamol (but this he has only heard), it might also filter out the rest of the unwanted stuff. Unfortunately, SWIM does not have enough knowledge of chemistry to know whether it would work or not.

By the way, SWIM has now come to the conclusion that fears about codeine loss with the activated carbon method are mainly unjustified. SWIM performed his first carbon filtering with only 160 mg (no tolerance) and, although initially weak and disappointing, a while later the effects peaked unexpectedly and lasted for a long time. SWIM did a bit of subjective analysis based on previous experiences and believes that no more than 20-25% of the codeine can be lost with the carbon method. Which is a very reasonable price to pay for the almost perfectly clear liquid that carbon filtering yields. For this reason, SWIM does a final carbon filtering on no caffeine containing tablets as well.

kant added 22 Minutes and 25 Seconds later...

Originally Posted by Synchronium

If the entire tablet dissolves, paracetamol 'n' all, then you can't separate the wheat from the chaff by their solubilities.

Common sense really.

Well, as far as my chemical intuitions go, I think a particle that happens to be in water is not yet a particle really dissolved in it. So you can grind your paracetamol in as fine a powder as you can and pour it in water, but only 500 mg will still be dissolved in 50 ml. So, if a soluble tablet simply turns into very small bits of paracetamol, these particles are still floating passively in the liquid and will still filter out through a coffee filter or carbon, while the amount of paracetamol that properly "dissolves" is determined by a chemical constant.

But these are just guesses. I don't know what water solubility really is and how it is determined.

[Synchronium]

My original post was wrong:

If the entire tablet dissolves, paracetamol 'n' all, then you can't separate the wheat from the chaff by their solubilities.

Common sense really.

Please see this post for the right answer: LINK

[davestate]

Originally Posted by Synchronium

If the entire tablet dissolves, paracetamol 'n' all, then you can't separate the wheat from the chaff by their solubilities.

Common sense really.

Sorry bud SWIY is wrong there. SWIyou is thinking of dispersible aspirin, which includes a compound which makes the aspirin actually soluble. The illusion that effervescent co-codamol is actually water soluble is because most people take 2 in a large glass of water.
Small amount of paracetamol + large amount of water means it will dissolve, in CWE amounts this ain't the case.


Now, the MAIN and most important reason not to use fizzy tabs is because of the INSANE sodium content, approx 400mg's of sodium PER TABLET! This cannot be removed, and is bad bad BAD for SWIyour kidneys.
SWIM has made a post on this before
http://www.drugs-forum.com/forum/sho...2&postcount=22

The maximum recommended level of sodium intake is 2,300 mg per day. It seems like a good idea on paper, and if it wern't for the sodium, it'd be the best! However take it from SWIM, it tastes vile, even more so than usual and makes you feel like crap after. Lesson learned for swim.


He will say however that adding 2 fizzy tabs into a cwe of normal tabs helps break up even small chunks of paracetamol, meaning the extraction is more efficient, if a little longer and more prone to clog filters

Reputation Comments on this post:

Thanks for clarifying things and answering questions. Level up! :)

[kant]

That is the answer I was looking for. Thank you!

[Synchronium]

Originally Posted by davestate

Sorry bud SWIY is wrong there. SWIyou is thinking of dispersible aspirin, which includes a compound which makes the aspirin actually soluble. The illusion that effervescent co-codamol is actually water soluble is because most people take 2 in a large glass of water.
Small amount of paracetamol + large amount of water means it will dissolve, in CWE amounts this ain't the case.

Yeah, I figured they'd be like the aspirin. I edited my original post, thanks for pointing that out.

[Sushi]

Originally Posted by Synchronium

If the entire tablet dissolves, paracetamol 'n' all, then you can't separate the wheat from the chaff by their solubilities.

What happens if the tablet is put into cold water? Is paracetamol in effervescent tablets more soluble in cold water than paracetamol in non-effervescent tablets? And what if the solution is put in a freezer? Will paracetamol precipitate or not?

In my first post I just summed up what Madlab read about the issue and my guess is that such questions as above can bother many people pondering on possibility of CWE with effervescent tablets. Using boldface and talking about wheat and chaff explains nothing and is not helpful at all.

[malsat]

Taking a potassium supplement would help balance your Na/K ratio, plus drinking a lot of water to prevent dehydration. Even so if it's just the occasional time you do it I doubt it would cause any hassle. I believe I've read that a high sodium intake is only a problem for people who already have high blood pressure. I eat insane amounts of table salt every day (for about the past decade) and recent bloodwork I've had done showed that my kidneys are just fine. YMMV.

That said, why bother with effervescent tabs? It only saves a little bit of time.

One more thing, why bother with charcoal filtration if you've no caffeine in your tabs? If you've only got a gram of APAP it seems a little redundant.

Bit of speculation next... passing the solution through an ion exchange resin could potentially replace the sodium with a less harmful ion...

[kant]

Okay, so SWIM, encouraged by the replies in this thread, has extracted about 8 soluble tablets in addition to the regular Co-Codamol ones he had left in an insufficient amount. So, according to davestate, there should be about 400x8=3.2 g sodium, or whatever they is meant by "fizzy base" in the instruction. The solution tastes disgustingly sweet, apparently the carbon didn't filter any of the base out.

3.2 g isn't anything, right? SWIM did a research on reccommended sodium doses, it was something like 2.4 g a day. That's good, SWIM will now imagine he's neglected his sodium during the week and is now making up for valuable chemicals lost.

[Sushi]

^^^
Ability to admit one was mistaken is always highly commendable

Originally Posted by malsat

That said, why bother with effervescent tabs? It only saves a little bit of time.

Because it can happen one will have a chance to acquire some of them. For example, SWIM could get some effervescent tabs as a gift and was wondering whether they would be useful at all. And their codeine content (30mg) is very tempting when compared to non-prescription pills (15mg).

[malsat]

Originally Posted by Sushi

^^^
Ability to admit one was mistaken is always highly commendable




Because it can happen one will have a chance to acquire some of them. For example, SWIM could get some effervescent tabs as a gift and was wondering whether they would be useful at all. And their codeine content (30mg) is very tempting when compared to non-prescription pills (15mg).

That makes perfect sense! TBH, just this week SWIM got ahold of some 30/500 effervescent tabs and was pleased that he didn't have to spend any time grinding them. Thought they were wonderful really! And considering that few tabs need to be used I don't think the sodium content is of any significance. But should one come across 8/500 effervescents then SWIM would ignore them unless they were the only option.

BTW, out of interest, where in the world are 15mg tabs available OTC?

[smeghead]

You could get 15/325's and 30/500 effervescent's in Spain (or at least SWIM did ~2 years ago) OTC, dunno if they've changed that now.

SWIM did a CWE using 32 effervescent 8/500's... If you leave the mixture in a cup for an hour or two the paracetamol sinks to the bottom just as normal.
The finished product tasted so vile SWIM puked before it had chance to take effect. not recommended.
Every time SWIM thinks about the taste of that horrible mixture he feels like puking - just like when SWIM overdid the cider by a litre or two and now can't touch another drop!

If you even put 2 tablets in a small glass of water, when the "fizziness" stops, you can see the paracetamol has sunk to the bottom of the glass. It's certainly possible to CWE them but as above SWIM's body puked up the mixture for a reason, I doubt it would have done him any good.

Doing 10 30/500's might be alright, no more than 10.

[Sushi]

Originally Posted by malsat

BTW, out of interest, where in the world are 15mg tabs available OTC?

In Poland, of course. One preparation is Antidol (15mg codeine + 500mg paracetamol), the other is Thiocodin (15mg codeine + 300mg guaiacolsulfonate). Both are non-prescription behind the counter and there are also other similar medications (Ascodan, Codespan, Nurofen Plus, Solpadeine) although their codeine content is lower (8, 10, 12.8mg).

Originally Posted by smeghead

SWIM did a CWE using 32 effervescent 8/500's... If you leave the mixture in a cup for an hour or two the paracetamol sinks to the bottom just as normal.

Madlab did a CWE using 2 effervescent Efferalgan tabs (30mg codeine + 500mg paracetamol), proceeding just like with CWE of any other pill, i.e putting the solution in a freezer first, then filtering it in a refrigerator. An amount of precipitated para (eyeballed, she admits) was definitely smaller then 1g, however. It was 300-400mg at the most. And yes, the taste was vile, much worse than the obviously bitter taste of a solution obtained from Antidol pills.

Originally Posted by Piglet

There is a pH buffering agent in there that keeps the APAP in solution. Make the whole thing acidic and it will drop out of solution.

This could be an explanation of the small amount of precipitated para. What could be done to make the solution acidic? Some simple tips for a layman would be greatly appreciated!

[Piglet]

There is a pH buffering agent in there that keeps the APAP in solution. Make the whole thing acidic and it will drop out of solution.

[malsat]

^^ Citric acid can be bought in Asian food stores, or else a person could add vinegar or lemon juice. Easy acidification!

[konshuss]

My flying squirrel has the same question as Sushi -- will altering the pH of the effervescent solution help precipitate out the Paracetamol?

The squirrel happened upon a nice pharmacy that had OTC 30/500's whilst gliding between trees in Asia.