Airless packaging with alcohol

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Airless packaging with alcohol

Posted by belassi on September 30, 2016 at 12:01 am

I have for a long time wanted to be able to use a lot more than 0.2% of glycrrhizic acid in a skin cream. The problem is, 0.2% is the limit solubility in pretty much anything except ethyl alcohol. It’s quite soluble in say, 25% ethanol.
Unfortunately all my attempts to use it resulted in unpleasant crystal precipitation because the alcohol evaporates out of it and escapes.
Now that I have airless pumps in stock, I am wondering, it it is maybe worth trying this concept again? Will the pump resist say, 5% alcohol OK?

belassi replied 7 years, 7 months ago 4 Members · 9 Replies
9 Replies

beautynerd

Member
September 30, 2016 at 6:20 am

Can’t answer the packaging question but isopentyldiol is also an effective solvent for your active.

http://www.thesoapkitchen.co.uk/acatalog/PDF_IPD_MMB_in_SOFW_0_.2015.pdf
johnb

Member
September 30, 2016 at 7:55 am

The potassium, sodium and ammonium salts are soluble in water.
belassi

Member
September 30, 2016 at 3:59 pm

Elise thanks for that. Heaven knows how I’m going to obtain that in Mexico…
belassi

Member
September 30, 2016 at 4:11 pm

Johnb: Do you think I will be able to convert the pure acid to the potassium salt? Would it be as simple as reacting it with potassium hydroxide using 1 mol to 1 mol?
Bill_Toge

Member
October 1, 2016 at 6:48 pm

in my experience, airless packaging is very robust; as long as the closure fits properly and consistently, you shouldn’t have a problem with an alcohol-containing product
belassi

Member
October 1, 2016 at 8:11 pm

I’m going to see if I can obtain isopentyldiol in Mexico because it’s a good stabiliser for the vit C compound. Thanks for your answer Bill. Having had some success with converting the pure acid to the dipotassium salt I think I will use that instead which means I don’t need alcohol.
belassi

Member
October 5, 2016 at 4:06 pm

Can’t find this in Mexico and for that matter, I can’t find a US supplier either.
beautynerd

Member
October 5, 2016 at 4:52 pm

So far I’ve been buying smaller quantities through this UK reseller. Shipping costs are reasonable.

http://www.thesoapkitchen.co.uk/cgi-bin/sh000002.pl?WD=isopentyldiol&PN=Isopentyldiol%2ehtml#SID=55 

They have pack sizes of up to 10 kg. Unsure if shipping expense gets prohibitive when purchasing in bulk.
belassi

Member
October 5, 2016 at 5:48 pm

At 1Kg the shipping cost is twice the price of the product. I think I will use my alternative solution to this problem, which is to synthesise the dipotassium salt which is soluble, rather than dissolve the pure acid in DPG. Thanks for your response.