[Abdullah]

Gordof said:

hi 

you will always have some Migration with this kind of conservator. it is not important due to the fact that the emulsions oil and water phase are always in the balance of the materials it is normal and nothing to worry about. 

0.25 % Methylparabaen is the maximum Solubility in the water phase but you normally use 0.2-0.1% in the Product in combination with 0.1-0.05% Propylparaben. 

The two Phases of the Emulsion will be in contact and therefore The paraben will be present in the oil as well as in the Water phase “used MEthylparaben in the water phase will be compensated from the oil phase until it is in balance. 

It is beneficial to solve it in the water phase due to the higher concentration at the beginning at the water phase all bacterial will be eliminated.

hope that helps

Thanks

[Abdullah]

Gordof said:

without knowing it for sure my instinct would say SLES is more aggressive. but the concentration is very low so I don’t think there will be a difference if the target group is not completely sensitive. 

IF you wanna make a Cream I would look for alternatives because both are very foamy and that would lead to bubble build-up on the skin. 

Thanks 

What anionic emulsifier do you suggest for pH 4 emulsion?

[Abdullah]

@vitalys do you have the PDF of 3d edition? 

[Abdullah]

What other ingredients do you have with percentage and order of addition?

[Abdullah]

Sorbitan Caprylate (and) Glyceryl Oleate increases the viscosity up to some point. After that it will decrease it.

[Abdullah]

Perry said:

@Abdullah - an excellent tool…

Google Trends

Thanks

[Abdullah]

Perry said:

According to Google searches, Ginger Lilly shampoo is recently popular 

Where do you check what is currently trending?

In my Google search it brings nothing serious. 

[Abdullah]

PhilGeis said:

Right - does seem confusing.couternintuitive.  These were different tests and one has to take published data as they are.
Didn’t inlcude that and other specific testing data in 3rd ed. for that reasoin.

Thanks 

On type of tests, one is serial dilution test and another is suspension test. any comments on them that what do they mean here and what is the difference? 

[Abdullah]

PhilGeis said:

MIC - the cells are alive but are not growing.  If you removed those cells from exposure to formaldehyde and put them in medium without the formaldehyde, they would grow.
Minimal Germicidal concentration.  Those cells are dead.  If you put them in medium without formaldehyde, they would not grow.

@@PhilGeis so if the MIC is 125 ppm formaldehyde to prevent growth of a bacteria, shouldn’t it be more than 125ppm not less to be able to kill that bacteria? 

Chart is from the book: cosmetic Microbiology: a practical approach

[Abdullah]

PhilGeis said:

Minimal /lowest concentration, in context of the test ,that rendered all cells nonviable.  No growth after agent was removed - neutralized.

@PhilGeis am i understanding it correct? Both MIC and minimal germicidal concentration is lowest concentration that stops the growth of organisms. So what is the difference? 

[Abdullah]

Mayday said:

Abdullah said:
[…]Sodium phytate is expensive and i am selling low price products.

Considering citric acid is cheap and you already have it in your formula, have you considered chelating with it? Would have to adjust pH down, but it sounds possible. And IDK how it would fare compared to dEDTA.

It is much weaker than EDTA. Like more than hundred times.

[Abdullah]

Thanks for the book

[Abdullah]

Mayday said:

@Abdullah Warning that sodium phytate will probably need more pH adjustment then disodium EDTA. At 0.05% NaPhy, 0.35% NaBenz, I needed 0.20% citrate to get to pH 4.4 from 10.9

Of course i will adjust the pH no matter what i use. 

Sodium phytate is expensive and i am selling low price products.

[Abdullah]

PhilGeis said:

Dave Steinberg’s books are excellent but I’m not aware he addresses the organic acid combination.  I’d worry less about synergism than, as Mark said, efficacy of comnbinations.  I know it takes a lot of resources but once you’ve established a good combination you can  prob reapply with confidence.  P&G did this with isothiazolinone/benzoate/EDTA in all its shampoos through all versions for over a decade.  Benzoate/Benzyl alcohol/EDTA was another combination that carried over well. - in shampoos atd up to neutral pH.
Alternative systems can work but aren’t so versatile.

Does Dave Steinberg have book about preservatives? 

[Abdullah]

Mayday said:

Abdullah said:

So what is causing tetrasodium EDTA not chelate iron at pH 4? 

Hi again @Abdullah ????

I can’t answer the chemistry question, but I have found a reference to the fact that each EDTA has their own pH at a standard 5% aqueous solution. They referenced the British Pharmacopoiea, which I do not have access to currently. My guess is that the pH of the EDTA corresponds to the pH range it is effective in.

I could be wrong, but the range for tEDTA (8.5-10) tracks with how I’ve seen it recommended for use in alkaline solutions, soaps, etc. So for yours you should use Disodium EDTA. Can also consider Sodium Phytate or Tetrasodium Glutamate Diacetate, as I believe those are effective at low pH.

Thanks

[Abdullah]

0.1-0.3% caprylyl Glycol or EHG both increase the penetration of other preservatives in microb cells so other preservatives function much better.
Glyceryl Caprylate also does the same thing and i like it even more because it is cheaper and also increase the viscosity of surfactants.

I prefer sodium benzoate over potassium sorbate because it is less expensive and more gentle. Also in surfactants, it functions better. 

[Abdullah]

vitalys said:

@Abdullah The Stratum Corneum is a pretty strong shield against sunbeams. When SC gets damaged or altered with any chemical or mechanical agent the shield becomes weak or thin, which makes lively skin cells vulnerable to solar radiation. The latter induces inflammatory reactions as well as the alterations from the damaging factors (e.g. acid peelings). 

Abdullah said:

And is this sensitivity only when AHA is on top of skin or even after some time when it is rinsed off? 

The hypersensitivity will last until the skin barriers are completely restored and inflammation is eliminated. 

@v@vitalys hey i was reviewing my questions and seeing your comment, another question came to my mind?

After chemical exfoliant (lactic acid or glycolic acid), how many days minimum and maximum will the inflammation last?

I mean if i am applying 10% lactic acid Evey night, does it mean my face is always in inflammation? 

[Abdullah]

DMDM hydantoin has 2 times more 5,5 dimethyl hydantoin than actual formaldehyde.
5,5 dimethyl hydantoin 36.3%
Formaldehyde 17.39%

Then how can it releases 2x formaldehyde per 5,5 dimethyl hydantoin when there is only 0.5x formaldehyde available per 5,5 dimethyl hydantoin in there? 

[Abdullah]

Sodium benzoate+phenoxyethanol is a good combination. I would add 0.1% caprylyl Glycol it it instead of EHG. It is cheaper and more water soluble and almost same effective.

[Abdullah]

Perry said:

I once made a big batch of white conditioner. When I poured it out, there was a big yellow streak near the bottom. It turned out, I had unknowingly dropped a small metal “chuck” (device to tighten the mixer) in the batch. I think it oxidized.  Perhaps you have excessive metal ions in your water in one batch that you didn’t have in your other batch. 

I made both samples in glass jar, mixing with same type metal spoon and stored them in PET plastic bottle. 
I forgot to mention above, they both had 0.2% tetrasodium EDTA that i add to everything.

I will make another batch and see if that was the case.

About this metal oxidation, is it only iron that oxidizes is such products or any metal?

[Abdullah]

@ggpetrov what emulsifier are you using? 

[Abdullah]

They are often combined at 2:1 benzoate: sorbate so this may be a good ratio. 

[Abdullah]

You can use even 10% citric acid if you want. My point was with powder SLS will need 4% citric acid to adjust the pH to ~5 while with liquid 0.2% is enough.

[Abdullah]

@DAS is aeration the only problem?

[Abdullah]

Change your emulsifier