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#1

Given you can precipitate dissolved solids from reasonably dosed gear by placing in the freezer, is it viable to use this as a method for extracting the dissolved solids for a subsequent m.p. test? I was thinking; precipitate in freezer, filter, wash with chilled hexane to remove oil. Would this be enough to get pure solids, or would it need further recrystallisation?


#2

I don't know about the last part but I have read about people that have tested gear that way, although I have never done it myself.... Why would you want to get the pure solids from already made test anyway? If you want to test it why not just test it then heat it up so its back to normal...


#3

I don't know if you'd need to wash it. You'll get precipitation if you put it in a freezer probably, but it might not form solids, you might just get cloudy oil. If you're trying to test out a source, what you could do is get some wintrol or testosterone suspension. Then you wouldn't need to wash it, and since it's suspended instead of dissolved, maybe it'll be easier to seperate from the water.

What do you plan to do with it once you get it? Melting point test, or do you have access to something fancy, like mass spectrometry?


#4

Just the M.P. test, and possibly an optical rotation. If it turns out its a viable way of extracting gear then I would be able to get hold of optical equipment. The suspension idea is a good one, although I think they add PEG or something to micronize the particle size in suspension, so it wouldn't be ideal. I put a few vials of test enanthate in the freezer last night and they crystallised quite well so I might give it a shot. I'd like a solid plan in place before I risk throwing away decent gear though!


#5

I think that usually that would not work, but depending on the ester you probably could extract successfully with DMSO, and then recrystallize by adding water to the DMSO.

I did this successfully for the purpose of NMR analysis a long while back (more than 10 years) but don't recall what the compound was.

The compound would have to have a melting point well above room temperature for this to work. So for example, testosterone propionate could be a suitable choice, but nandrolone decanoate would not be.

For whatever reason, it can be surprisingly (to me) hard to get recrystallization in some instances from adding water. One could wind up with a cloudy mixture that stays that way. Patience will be a virtue.

In cases where the oil would remain clear in the refrigerator or freezer, but hard solids precipitate out, then yes those could be isolated as you describe.

In some instances you might aid the process by adding hexane, perhaps at equal volume, before putting into the freezer. This would be reasonably likely where a product is particularly concentrated, meaning that there is a substantial percentage of solubility enhancers. The solubility of the steroid could become much less on addition of hexane, even enough so to more than compensate for the added volume. However that would be something to try not with an entire batch but just as its own side experiment.


#6

Also: if I tried the DMSO extraction followed by addition of water -- probably 10 parts of water to each part of DMSO -- and there was a resulting cloudy mixture that never gave precipitate, I'd try extracting with chloroform. It might take a fairly large amount of chloroform to yield two distinct layers, as DMSO is miscible either with chloroform or water and I don't know the relevant partition coefficient.

Water washes of the chloroform layer would then be required to get rid of the DMSO.


#7

I like the DMSO idea, its definately a good choice since it should pull out the steroid and allow separation from the oil layer when adding water. Adding hexane BEFORE precipitation in the freezer is also a great idea too, and would make the resulting precipitate easier to wash.

I was quite surprised at how well the enanthate crystallised out of solution in the freezer, with hexane it could be even better. Thanks for the input Bill, your insights are appreciated.
I was also wondering if any crystallised samples would be pure enough to get a decent m.p. and optical rotation from. I was thinking that since we are doing a recrystallisation, that this should yield quite a pure sample, but then again I don't know much about likely impurities in steroid hormones.


#8

I don't know, it is possible that benzyl alcohol or BB might intersperse themselves in the steroid crystals.

I don't think that would happen with BA and the DMSO/water method, but it might be an issue with BB no matter what one does. But probably not a big deal, especially as you did obtain a good crystallization anyway.

In any case traces of BA, BB, or vegetable oil won't affect optical rotation.