[seaberry]

Hi! Sodium cocoyl isethionate can be annoying to work with. It doesn’t dissolve well in water or in oil on its own. 

There are two basic ways to work with it. You can mix it with a liquid amphoteric or non-ionic surfactant, such as cocamidopropyl betaine. It will take a while and maybe a little heat, but they should eventually melt into a smooth paste

The other way is to use an ethoxylated emulsifier such as Emulsifying Wax NF or Lotionpro 165. It will keep the SCI stable in the formula the same way it would stabilize oils. You may need around one percent emulsifier for every three percent oil. 

[seaberry]

Personally, I find safflower oil very lightweight and easily absorbed. It also has a high proportion of linoleic acid, which some studies found to be deficient in acne-prone skin.

[seaberry]

KatieW said:

OK if I substitute the Benzly Alcohol for Sodium Benzoate/Potassium Sorbate that should work better?

Ideally I don’t want to substitute the Btms 25 due to it’s conditioning effect it has on my hair. Is there anything else I can do to stabilise the formula?

Thanks so much for your help! 

BTMS’s conditioning effects come from its cationic (positive) charge. Because of the positive charge, it is incompatible with anything anionic, or negatively charged. 

Cocamidopropyl betaine is amphoteric, which means its charge may be positive, negative, or both depending on the pH. As Bill mentioned, this is likely why your shampoo is separating. 

If you want to keep the conditioning agents, the only way to make it stable is to remove CAPB and replace the preservatives like you mentioned. 

You may wish to replace the CAPB with a compatible surfactant, such as lauryl glucoside. 

[seaberry]

I don’t know nearly enough to help—but don’t you need in vivo testing to establish SPF numbers?

[seaberry]

I find that potassium cetyl phosphate is reliable and versatile, though the process can be less straightforward. 

[seaberry]

Eugene said:

Graillotion said:

Can not help without percentages, but agree with seaberry, as allantoin will only go into the water phase at about .5%.  A small additional amount can temporarily be tricked into solution with heat…but won’t stay there.
Mommy blogger sites like to try and get you to load things up, I think they get a cut from the repackers.

And my golden rule of cosmetics….Just because something is good at a low rate….does not mean it is better….at a high rate!

Panthenol - 5%
Allantoin - 5% 🤦‍♀️
Geogard - 1%

Thank you. So it ia fully my fault, lack of attention while reading allantoin allowed percentage, 0.1-2%…
Do you think there are enough soothing components to make this spray really working, if I add
Allantoin 0.5
Panthenol 9.5
?

5% allantoin makes sense. That’s never gonna dissolve. 

As most of your formula is water-based, 0.5% would probably be okay. 

9.5% panthenol would be fine from a stability standpoint, but that’s overkill. We don’t have tons of data on panthenol (relative to ascorbic acid, tretinoin, etc), but most of the studies we do have max out at 5% panthenol. 

But then again, I imagine this is for personal use, and even commerical products with 10% panthenol do exist, so you do you

[seaberry]

I want to hop on and say thanks to everyone as well! From those who are like living textbook with endless knowledge to share, to those who give blunt—and rock-solid—advice from their years of experience, to the intermediates with interesting questions that spark incredible discussions, the expertise and fellowship in this forum is so useful and so appreciated!

[seaberry]

It would really get you farther if you included the ingredient percentages. 

Panthenol is almost freely soluble in water (even 10% should be fine). So neither it nor the Geogard should cause issues at reasonable concentrations. 

Allantoin is likely the most probable cause. It’s generally only soluble around 0.5%, and even then it can be finicky. 

Overall, you may find better results by adding a polyol, such as butylene glycol at 1~5%.

[seaberry]

ozgirl said:

I remember this similar type of formula from Innospec https://personalcaremagazine.com/formulation-details/2564/bubble-scrub-butter where it required the addition of sodium chloride. Not sure if that would help in this case but it might be worth a try.

That is very interesting formula. If I understand correctly, that’s 50% oil “emulsified” by ~40% surfactant and thickened by NaCl, which is wild. I’m gonna have to take a deeper look at this for sure. Thanks for sharing! 

[seaberry]

chemicalmatt said:

@seaberry I may be stating the obvious here: DEL the SCI altogether. The oil component (identity?) is doing the heavy lifting in makeup removal, your surfactants are mainly employed to remove both oil solvent and makeup. Why not select another nonionic surfactant to solvate/remove the collective crud or just q.s. with the glyceryl ester?

That does seem like a good idea. You’re absolutely right about the oil (I’ve been using ethylhexyl palmitate or safflower oil for testing) solubilizing the makeup, and then the surfactant to rinse everything away. 

The makeup melting works fine, but I’d prefer a cleaner rinse. The above formula with extra glyceryl ester in place of SCI leaves a thick, waxy film on the face, unfortunately. 

What surfactants would you consider for this purpose? I understand most standard non-ionics include water and would thus necessitate a preservative. 

[seaberry]

Mic001 said:

what is the pupose of the formula? Seems like it might be a polarity issue. 

The goal is a makeup remover that rinses cleanly. 

Hm, I thought polyglycerin esters were non-ionic, which should play well with anionic SCI, right?

[seaberry]

Ceteareth-6 olivate from Hallstar also makes fluid emulsions. Some combination of this with Aristoflex or GSC should easily manage 15% lipids. 

[seaberry]

@LuisJavier This link shows sorbic acid’s strong antibacterial activity towards S. aureus and weaker activity towards E. coli (Gram negative), which showed synergistic effects when paired with EDTA. 
https://ssrn.com/abstract=3439954

[seaberry]

@LuisJavier
That’s just me missing the context, ha. 
I was speaking in general terms about the use of potassium sorbate and sodium benzoate together. In theory, the two could negate the need for phenoxyethanol altogether in the correct pH and formulation, though it’s not the most robust combination as a stand-alone preservative system. 

[seaberry]

I realized I missed something! I mistakenly assumed your surfactants were all cationic-compatible. SCI is anionic and is not compatible with GuarCat, which I mentioned above. 

Hope you find a thickening system that works for you!

[seaberry]

@LuisJavier To my knowledge, potassium sorbate does better against gram negative but worse against gram positive bacteria compared to sodium benzoate. When used together, they can also boost each other’s resistance to mold. 

[seaberry]

Yes, thickening with NaCl can be hit or miss depending on the formula. You may want to explore polymeric thickeners like acrylates/c10-30 alkyl acrylate crosspolymer or some type of carbomer (many cannot thicken lower than pH 6 or so), but these may also require neutralization with an alkaline substance as well. 

Seeing that you have quats in the formula, I imagine you want at least some conditioning properties? In that case GuarCat (INCI: hydroxypropyltrimonium guar gum) may be a good option to add conditioning and thickening properties. 

[seaberry]

Solubilizing SCI can be tricky. With those amounts, try stirring gently over a water bath with no blending. It should become smooth with a little time. 

If your current batch has lathered too much, the foam should subside in a day if you just leave it. 

For thickening, formulas with CMPB can usually be thickened with a bit of sodium chloride (table salt). Try adding 1% to the water or finished product and see how you like it. 

[seaberry]

@ZleyHoldings Thanks. Do you think the combo of pentylene glycol, potassium sorbate, p-hydroxyacetophenone, and EDTA would be sufficient? 

@suswang8 Woops, must have missed that. Thanks for letting me know, I’ll go take a look.

[seaberry]

It depends on the formula and pH, but phenoxyethanol + ethylhexylglycerin is the popular Euxyl 9010, which should provide great broad-spectrum coverage.

Alternatively, phenoxyethanol + phenethyl alcohol can also provide robust coverage for ± bacteria, mold, and yeast. 

But be aware that ethoxylated non-ionic emulsifiers like polysorbates can interfere with phenoxyethanol. 

[seaberry]

singhc10 said:

I have worked with Eumulgin SG in a mineral sunscreen formulations. I think the main problem is total emulsifier in the formulations. Your oil phase is around 15-17%, and you will need 3.0-3.5% emulsifier. I will recommend going with additional non-ionic emulsifier either ethoxylates like oleth-15/ steareth-20 or you can use APG such as Coco-glucoside 

Thanks so much for your input! A few more questions: 
• I’m not really sure how my oil phase adds up to 15-17%. Isn’t it 10% from the triglycerides and cetyl alcohol? 
• Unfortunately, one of the requirements for the formula is no ethoxylated ingredients (the TEA is just for testing, it will be replaced by sodium citrate or arginine). Do you think glyceryl stearate or sorbitan olivate may work? 

Thanks again!

[seaberry]

You may also want to explore Acrylates / C10-30 alkyl acrylate crosspolymer, which is available from a number of sources under many different names. It has good electrolyte tolerance and can thicken up to 65% alcohol at least. It’s also generally cheaper than Polyacrylate crosspolymer-6 (Sepimax Zen). 

[seaberry]

I’m not sure if this would work for your intentions, but you might want to explore Pentsia powder (INCI: Adipic Acid/Neopentyl Glycol Crosspolymer), which looks like it has some very useful properties for powders and eyeshadow. 

[seaberry]

amitvedakar said:
May be similar. this is used for ADAPALENE material  (retinol group). 

Ah, I see. I’ve never heard of encapsulated adapalene personally, but there is this study I found, which calls them adapalene TyroSpheres:
https://pubmed.ncbi.nlm.nih.gov/29996653/

Formulator Sample Shop also sells retinol liposomes. 
https://www.formulatorsampleshop.com/FSS-RETINOL-LIPOSOME-p/fss60124.htm

[seaberry]

You mean encapsulation? Encapsulation (or microencapsulation) is a method in which active ingredients can be contained in micelles or liposomes, which can provide extra stability or penetration for some ingredients like retinol.