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why is gluconolactone crystallizing out of solution?
After 2 days I’ve noticed tiny crystals from the addition of gluonolactone that won’t dissolve upon shaking. Why is this happening? Will the crystals irritate the skin if still used? Is this a problem?
Formula is below:
aloe water
peppermint hydrosol
lavender hydrosol
witch hazel distillate
hydrolized oats
cucumber extract
allantoin
potassium sorbate
gluconolacctone
Thank you. -
8 Replies
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You would need to include percentages since this is a solubility issue.Lacking this, I would suggest Allantoin is your culprit, not the Gluconolactone. -
Hi Microformulation,
I’ve kept the gluconolactone very low at 0.3%, potassium sorbate also at 0.3% and allantoin at 0.5%. Some of the allantoin settles at the bottom as a white powder. However, the crystallization is a new experience since the addition of gluconolactone (which I had not been using before).
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Did you measure the PH ?
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pH is 4.62
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Alison said:Hi Microformulation,
I’ve kept the gluconolactone very low at 0.3%, potassium sorbate also at 0.3% and allantoin at 0.5%. Some of the allantoin settles at the bottom as a white powder. However, the crystallization is a new experience since the addition of gluconolactone (which I had not been using before).
So, you have some undissolved Allantoin in the product?
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You have to heat to about 50C for the Allantoin to dissolve properly
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Undissolved Allantoin needs to be fixed, as others mentioned by heating. Also, its solubility in water is around 0.5% so you are at the upper limit in your formula.
Since you say crystals formed only after adding Gluconolactone, I think this may be due to Sorbic Acid (from Potassium Sorbate) crystalizing out of your solution due to low pH. Check this out for more info:
https://www.jungbunzlauer.com/fileadmin/content/_PDF/PRINT_PROJECTS/Flyer/JBL_FL_How_to_use_Glucono-delta-Lactone_in_Personal_Care_2022-071.pdf
“Salts of organic acids used as preservative dissociate when added in solution. The addition of gluconolactone can lead to a drop of pH under the pKa. The undissociated form of the preservative becomes predominant (e.g. benzoic acid). Having a low water solubility, the acid form of the preservative starts to crystalize.” -
Sorbate is not enough of a preservative with or without gluconolactone. Please consider something more effective vs Gram negative bacteria.
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