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Stronger preservation system needed!! Please advise!
Hello all! My hair gel product is currently at a lab for Stability and USP <51> testing. I just received the 1 month update and the results were not favorable and I really need advice on how to strengthen my preservation system. Currently my formula is only being preserved with Optiphen Plus (INCI:Phenoxyethanol,Caprylyl Glycol, and Sorbic Acid)
Here are my results at 1 month:
For the USP <51> study, I do have some updates at Day 28 (end of the study).All bacteria are still <1.00-log CFU/gCandida is still at inoculation level of ~5.00-log CFU/gA. niger has had a slight increase and is almost at 6.00-logCFU/gThe USP <51> acceptance criteria requires “No increase from the initial calculated count at 14 and 28 days” for yeast and mold. Based on the results of the mold your product is not considered passing.Should I just scratch the Optiphen Plus or use it in conjunction with another preservative? Any suggestions on a preservative that could help me combat this issue?Thanks in advance!
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9 Replies
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Opti plus is very pH sensitive (to get the full benefit). (see the last word in the INCI)
You did NOT mention your pH….which would be critical.
Please also list all other ‘hurdle’ ingredients in the formula.
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Thanks for responding!
My pH is 6.75 per lab
If the pH is reduced any further my formula would be too cloudy. So this would be the lowest pH to preserve the clarity of my formula.
My ingredients are as follows:
Water
Ceteareth 25
Acudyne 1000
Peg 7 glyceryl cocoate
Peg 40 hydrogenated castor oil
AMP ( neutralization)
Optiphen PlusIf the pH is too high for Optiphen Plus I may need to change the preservative altogether. Any suggestions?
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What percentage of preservative did you use?
I suggest you use a blend that has parabens or IPBC in it witha a chelating agent.
There are a lot of parabens or IPBC in phenoxyethanol products.
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ph for sorbic acid needs to be below 5.5 if you have a high ph and your customer doesn’t mind using Paraben it’s the most efficient and safe one. if they do just use Phenoxyethanol around 1 % should be fin than I would say.
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Based on my poor knowledge - sorbic acid at this pH is not helpful. Even in marketing brochures, Phenoxyethanol with Ethylhexylglycerin is weak against A. niger at 1%. Phenoxyethanol alone is insufficient. I don’t think Phenoxyethanol with Caprylyl Glycol could be much better. Maybe add Chlorphenesin? It can be used up to pH 8 and it’s soluble in warm water. But it would be better if some expert like Phil could comment.
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Clearly your product sucks vs fungi and you’ve seen the good suggestions above — but increasing the phenoxy is not likely to help.
USP 51 is a very poor challenge test - any reasonable system should be eliminating/greatly reducing fungal counts.
Mold aspect of the test is real stupid. Inoculate with spores and fungal growth does not necessarily increase CFU. Likely the “small increase” is a result of mixing not growth, but that’s a technical detail . You should be killing not holding steady. -
@Abdullah I’m using the preservative at 1%
@Gordof I wish I could use Parabens but at the moment that’s not an option unfortunately.
@grapefruit22 I am looking into the Chlorphenesin because I see that it is compatible with Phenoxyethanol with Caprylyl Glycol.
@PhilGeis If USP 51 is a poor challenge test could you please advise what would be a more efficient and effective test to request the lab to perform. I don’t want to waste my money on unnecessary testing and this particular test is $2000. Please advise! Thank you!Thank you all for taking time to respond to my thread! Very much appreciated!
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Ask for the CTFA test and pursue elimination.
Chlorphenesin is largely an antifungal. It may help your system. -
@PhilGeis Thanks for the information!
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