Hydroxyethylcellulose and phenoxyethanol

Formulating

Hydroxyethylcellulose and phenoxyethanol

Posted by sandydijon on January 1, 2016 at 1:49 pm

Hydroxyethylcellulose and phenoxyethanol

are they compatible with each other? thinking about a clear serum. Thanks.

MarkBroussard replied 8 years, 11 months ago 4 Members · 10 Replies
10 Replies

Chemist77

Member
January 1, 2016 at 2:57 pm

Think they are, but it has low water solubility so keep it less than 1% I mean phenoxyethanol. Also please bear in mind that the recommended pH for this preservative 4.0-8.0, so go accordingly.
sandydijon

Member
January 1, 2016 at 10:52 pm

Thanks
Microformulation

Member
January 2, 2016 at 6:24 pm

Is this for a Facial Serum? If so, you may want to reconsider using Phenoxyethanol as a stand alone preservative.
sandydijon

Member
January 2, 2016 at 11:58 pm

I’m using
1% Phyenoxyethanol (with about 4% glycerin)
0.5% Potassium Sorbate
0.5% Gluconolactone (and) Sodium Benzoate
2% Black Willow Bark

Do you think it’s enough?

I’m going to do microbial testing by myself first
what is the passing rate?

CFU/ml - 1,000? 10,0000?

Thanks for commenting
MarkBroussard

Member
January 3, 2016 at 2:37 pm

@sandydijon:

You have plenty enough preservative in your formulation. Potassium Sorbate & Sodium Benzoate is a classic combination, the level of Phenoxyethanol is fine at 1%.

On the microbial testing … Don’t take this the wrong way, but if you don’t even know the passing rate … I would recommend that you use a qualified testing lab. The microbial plate count tests are only about $18 to $20.
sandydijon

Member
January 3, 2016 at 7:35 pm

$18 to $20? I got a quote for $450 per formula for preservative challenge. Yeah Eventually I’m going to send it to the lab when I got my final formula done.
Microformulation

Member
January 3, 2016 at 7:50 pm

$18-$20 dollars is a quote for APC Plate counts or a “snap shot” of the existing levels of contamination in your product. That is where the thresholds of CFU/ML come into play. Test kits measure this, but not nearly as accurately as a validated lab. At that price you are best to send it off.

PET or Challenge Testing is a more dynamic test and simplistically checks the ability of your preservative system to prevent contamination over time. This test I highly doubt you are able to do yourself. This is the test that would run in the range of $450.
MarkBroussard

Member
January 3, 2016 at 9:54 pm

As an alternative, you can use Schuelke & Mayr MikroCount Combi Test kits to determine if you have any microbial contamination problems prior to doing a Preservative Challenge Test.

But, yes, $18 to $20 for a plate count done by a lab is an accurate price.

For the Preservative Challenge Test, you’re going to have to use a testing laboratory.
sandydijon

Member
January 4, 2016 at 5:31 am

ok I have about 5-6 products so I guess I will spend about 3k in testing. Do I need testing for an oil serum? only oils and essential oils in a 15ml dropper bottle.
MarkBroussard

Member
January 4, 2016 at 2:05 pm

It is your legal responsibility to ensure that your product is safe for use by consumers. From a legal liability perspective, it is best if you Preservative Challenge Test any product you bring to market. All it takes is one problem and you’ll burn up $450 dollars in legal fees in an hour and without any evidence that you took the necessary steps to ensure your product was safe for use, well, you’ve got real problems.