Q for Bill Roberts, purification of AAS

[BA69]

What solvent system does one use to recrystallize raw testosterone enanthate for example? My research is indicating that an aqueous methanol solution would work... in what ratios? What about boiling the raw test in hot water and adding drops of warm methanol gradually until it dissolves? What about short esters like prop?

Would I need to rince my product in ice-cold water several times to remove any trace of methanol? What would be the best way to dry the product?

Thanks for any info you can provide.

 

[Bill Roberts]

This kind of question can really only be answered by having done the experiment. I've never worked with testosterone enanthate other than simply using the powder with no treatment other than filtration after having dissolved it.

Where methanol is a good solvent for a lipophilic compound, which TE is, addition of water is often a good way to crystallize but there are also exceptions where one gets a cloudy mess. Only experiment can tell which can occur, so far as I know.

It would be desirable to add only enough water to achieve fairly high recovery of TE, with losses that were considered acceptable, but not a recovery of virtually 100%. When the recovery is extremely high, it becomes quite likely that impurities, unless water soluble, are also being recrystallized at high efficiency, making the procedure pointless.

I don't know whether heavy metal content, if present, would likely be reduced by the procedure. It could well be the case, at least in some instances.

 

[BA69]

I found the following information:

Japanese Patent JP56002999
Abstract: PURPOSE: To increase the crystal size and the bulk density of crystallized testosterone enanthate, and to improve the efficiency of extraction and filtration of slurry, by crystallizing crude testosterone enanthate in a mixed solvent comprising specific amounts of water and alcohol.

CONSTITUTION: Crude testosterone enanthate of formula is dissolved in an aliphatic lower alcohol (pref. methanol). The solution is cooled near the crystallization temperature, and mixed with 10W50wt%, pref. 20W30wt%, based on the alcohol, of water, and recrystallized at ?0°C, pref. ?-10°C.

Do you understand this terminology; "mixed with 10W50wt%, pref. 20W30wt%" ? I'm not understand this whatsoever.

Is there a way to find out what solvent ratio they used? I'm basically asking for some help on how to research this more deeply.

Here's the link
PURIFICATION OF TESTOSTERONE ENANTHATE - MITSUBISHI CHEM IND LTD

Thanks again Bill.