[Hairlover]

Hi,

I have a question regarding the stability of my shampoo. I have already checked all the other topics regarding my question, but couldn’t find the right answer, so I’m posting it here.

I’m formulating shampoo for my client. We have Coco glucoside, sodium cocoyl glutamate and CAPB as surfactants, then we have a few moisturizers (B5, propylene glycol). And an additional of 1% urea.

I have lowered the pH to 5.5 with citric acid (use around 0,8%). After a few months (3+) pH is still the same.

My question: Is it necessary to stabilize the urea with a buffer solution regarding the use of a really low dosage of urea (1%). Should I expect to have problems regarding urea decay later (let’s say after 1 year).

Any suggestion /experience in this field is welcome, thank you in advance for your help.

[Hairlover]

Hello,

I don’t know if this topic is the correct one for my formulating problem because I don’t know if the primary cause is BTMS.

I’m working on a leave-in conditioner with SPF protection.

Draft formula:

Phase A

Behentrimonium methosulfate (80%)= 2.2%
Ceteary alcohol= 2.0%
Oils=5.0%
UVA filter (Diethylamino Hydroxybenzoyl Hexyl Benzoate= 2.0%
UVB filter (ethylhexyl methoxycinnamate)=3.0%
Dimethicone 350= 2.0%

Tocoferol= 0.05%

Phase B

H20
Cetrimonium Chloride (25% solution)= 3%
Na EDTA= 0.1%

Phase C

Ciclomethicone= 1.0%
Panthenol 75%= 2.2%
Benzyl Alcohol+ Dehydroacetic acid= 0.6%
Hydrolized protein (20% solution)= 1.0%
Hydroxy Propyl Methyl Cellulose= 0.4%
Glycerin= 2.0%
There is a slight separation on the bottom when I put the product on a centrifuge at 3000 rpm for 10 min. It looks like a small drop of water.

I have tested a lot and come to a conclusion. If I make an emulsion and add all the above ingredients except Hydrolyzed proteins and the preservative - the emulsion is stable. If I add or preservative (Benzyl Alcohol+ Dehydroacetic acid) or hydrolyzed proteins or both - a drop of something (probably water) occurs on the bottom of the centrifuge tube.

So it’s probably something wrong with the interaction between proteins/preservatives and the emulsion itself.

What is the cause of this separation? I have tried so many things:

-More or less emulsifier

- More thickener of water/oil

- Other hydrolyzed proteins

-More /less homogenization in the process

Based on my theoretical knowledge all the above ingredients are compatible.

If any of you have any idea what is wrong. Please help.

Best regards

[Hairlover]

Hi, Thank you for your answer.

The test that I did- shampoo with urea and shampoo without urea, there are big difference in hair softness and overall feeling of the hair. This is the only practical reason, that I included it into shampoo.

Does anyone else notice the softness hair (like silk) after using the urea in shampoo or other haircare products?

[Hairlover]

Hello to all formulaters,

Firstly thank you all for you replies.

As you suggested above, I have tried:

- Different preservative system.
I have tried with the metyl paraben (disolved in propyene glycol and added in C phase) and blend of Phenoxyethanol and ethylhexylglycerin. The results was the same. Water or some other liquid on the bottom. Maybe the problem is really too low dosage of cetearyl alcohol and HPMC?

The viscosity is really a bit low, but the Cetrimoum Chloride makes it harder to increased it. Maybe there is some hack how to solve this problem or the solution is to just add a lot of thickener?

Note: I didn’t include any proteins and the emulsion without preservative was stable.

Photo on the left: with addition of metylparaben , on the right with the addition of Phenoxyethanol and ethylhexylglycerin.

note: The difference of the colour is from the different mixture of oils (more argan on the left).

Any suggestion what is wrong and what to try next?

• This reply was modified 12 months ago by  Hairlover.
• This reply was modified 12 months ago by  Hairlover.

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[Hairlover]

Thank you for your reply and help. I appreciate it – really.

The oils are coconut oil and argan oil.

Which emulsifier do you suggest or will fit more for the chosen oil system?

As for preservatives – noted. I will use methylparaben.

What exactly do you mean by suspending an agent? I used Hydroxy Propyl Methyl Cellulose for the matter of water phase thickener and overall stability enhancer. Is this a bad pick for the whole emulsion system? Should I use another- like you suggested carbomer?