Opioids Codeine Phosphate solubility

[c2h60]

This is (no really) a purely academic question about relative solubility. I am familiar with and have read the threads/dissertations/haiku on CWE: I am not interested in that.

On to the meat course. I understand that paracetamol is very highly soluble in isopropyl alcohol at 15C. I also understand that codeine phosphate is only 'slightly soluble' in isopropyl alcohol at 15C.

I have two questions. 1) is my understanding of the relative solubility of paracetamol and codeine phosphate in isopropyl alcohol broadly correct? 2) If so, if one were to crush up a quantity of 500mg Paracetamol/8mg Codeine Phosphate pills and then 'rinse' the powder in small quantities of isopropyl alcohol, would the paracetamol dissolve and pass through the filter paper leaving the codeine phosphate behind?

 

[Ksa]

Unless you are rinsing large quantity of powder, such as 1Kg, I cannot approve the use of volatile solvents on a routine basis because it is a fire hazard. Also, use acetone because codeine is still soluble in alcohols, around 2.5mg/mL average at 24C.

Once you rinse that large quantity in acetone and filter, you should obtain a mix of codeine, pill fillers and traces of acetaminophen and caffeine. A kilogram of powder should be rinsed with 5L of acetone and stirred mechanically for 2 hours for the acetaminophen and caffeine to be fully dissolved at room temperature. You can then filter and dry the powder. This operation is highly hazardous due to risk of fire, and should only be done once every few years max, in a sand area, outdoors, away from things that can catch fire.

 

[SS373dOH]

It might work if it were 30mg acetaminphen/30mg codeine.. But I think a 62.5/1 ratio is too large for it to work.

 

[sekio]

It's important to realize that pills usually don't contain exclusively drugs: they usually contain a good amount of insoluble/very poorly soluble binders. Tylenol 1s/3s especially. So the real issue, and one you'll need to solve by experiment, is whether or not the isopropanol can free the codeine from the binders, and whether or not it results in a filterable liquid/solid mix.

Codeine phosphate's solubility in ethanol is actually closer to 0.75 g/mL. I'd expect it to also be soluble in isopropanol, too. So I agree that you'll end up washing otu both the codeine and acetaminophen.

PS. Acetone/isopropanol are flammable, but if you have a well ventilated area it is not worth being paralyzed with fear. Keep sparks and flames away and you'll be fine.

There really is no easy way to get codeine out. The ideal solvent is actually ether.... extracts freebase codeine but not caffeine...

 

[Ksa]

^ Yes, also OP keep in mind the reason why you're doing that extraction: To prevent harmful chemicals(acetaminophen) from harming your liver and organs. If in order to do that, you expose yourself to VOCs, breath in acetone vapors routinely etc. you partially defeat the purpose. Use VOCs when water will not do the job, if water does the job, use water, not VOCs.

 

[sekio]

That's strictly true, but the entire reason he's discussing this is because water doesn't extract what he wants it to.

Acetone and isopropanol are very excusable; your body makes acetone as a product of fatty acid metabolism and can even use it as a caloric source, after all. People on the Atkins diet should be familiar with that. And isopropanol is conveniently oxidised to acetone by alcohol dehydrogenase, with no pesky toxic acetaldehyde involved. Isopropanol also has a fairly low volatility due to hydrogen bonding. So in total I would rather breathe acetone vapours on a regular basis than consume acetaminophen, actually.

 

[Ksa]

That's strictly true, but the entire reason he's discussing this is because water doesn't extract what he wants it to.

Acetone and isopropanol are very excusable; your body makes acetone as a product of fatty acid metabolism and can even use it as a caloric source, after all. People on the Atkins diet should be familiar with that. And isopropanol is conveniently oxidised to acetone by alcohol dehydrogenase, with no pesky toxic acetaldehyde involved. Isopropanol also has a fairly low volatility due to hydrogen bonding. So in total I would rather breathe acetone vapours on a regular basis than consume acetaminophen, actually.

That's why I used the word "partially' lol. You're right, back in chemistry I liked how acetone vapors smelled, especially diethyl ether, I smelled these for very long and not much happened. With the flammability hazard I guess it varies on the person. Back in Chemistry, personally, I felt in more danger when shaking a 1L ether filled extraction flask, relieving pressure every 3 seconds, then when I was handling hydrofluoric acid, K2MnO7 or LDA. The reason why I don't like alcohol is because when it caches fire, the flame is blue and barely visible to the naked eye, so when you notice there's a fire it's cause you're on fire or it's too late.