[lewhitak]

The Carbopol Aqua SF-1 has a few things to watch out for, such as when you add in ingredients like the aloe vera. If you add too much aloe or add it at the wrong point in your formula you will see destabilization. 

Have you tried removing the aloe to see how if changes the stability?

[lewhitak]

First try grinding down the native pigment to the finest you can by using a coffee or spice grinder from Amazon. After this, you can disperse the dry pigments using a glass muller or other paint tools (like this) in your oil phase to wet out the pigment properly. Use high shear to add to your formula. You would need to characterize your grind to make it reproducible with a grind gauge or similar. 

You will likely need to fiddle around with the mix times to find how you can achieve the best grind. 

Orrr as @ngarayeva001 suggested you purchase pigments where the work has already been done and make your life a heck of a lot easier.

[lewhitak]

I recommend purchasing pre-dispersed and milled colorants for use in your base. You can only break down the particle size to a certain point with the methods you have available. To get a finer particle size typically a mill is used.

[lewhitak]

I am not sure if it would apply here, but vanilla fragrances can cause a brown discoloration to develop in formulas. Have you tried a sample without the vanilla?

[lewhitak]

@Dr_Sara
Won’t excess glycerin wash off with the water used to wash with a soap? Since it’s water soluble and not substantive to the skin even an excess deposition of glycerin should wash off. 

[lewhitak]

Personally, I would not use a penetration enhancer at all. In theory, if you have an active peptide there that will bind with the EGF receptor you can totally just have a topically applied product with no enhancer. On your side is the size of the peptide and the fact that the receptor it would bind to is trans-membrane. This means you will just need a formula which is very compatible to your peptide and keeping it active. 

Adding a penetration enhancer could possibly reduce your activity if you’re not using something compatible.

[lewhitak]

@Pharma
You’re welcome! After the grapefruit seed extract debacle I rarely trust “natural” preservative blends ,unfortunately. I don’t get how these can be sold as preservatives either! They are frequently heavily marketed on DIY sites as well, which unfairly targets home crafters.

[lewhitak]

Why do you want to use the leucidal liquid?

https://pubs.acs.org/doi/full/10.1021/jf5063588

[lewhitak]

Hello!
I am currently trialing the Tego Care PBS 6 and utilize the hot-cold process to create emulsions. What are you specifically interested in? 

Just a few points:
- We use a Silverson rotor/stator mixer and have found success with hot-cold but avoiding oil pooling at the surface is important.
- 3-4 days of settling as instructed by Evonik does help form more of a “body” to the cream, but generally I am not seeing a large increase in viscosity but more of an increase in the “slip” feeling of the cream.

The test formula which resulted in a pleasant low-soaping thick cream is as follows:

Water

---

q.s.
Propanediol

---

3.00%
Flax Seed Oil (Unrefined)

---

15.0%
Tego Care PBS 6

---

2.00%
GMS Pure

---

0.75%
Cetyl Alcohol

---

0.75%
Sepinov WEO—-0.80%
Euxyl PE 9010—-1.00%

Sorry I can’t help more with your other questions, but let me know if I can do anything else.

I actually requested this material after seeing a recommendation in a thread by @Bill_Toge. Maybe he can offer more help?

[lewhitak]

Here is a good thread to reference, especially for information on the chelator:

https://chemistscorner.com/cosmeticsciencetalk/discussion/751/preservation-strategies-for-natural-formulators#latest

[lewhitak]

Hello Wickers!
Unfortunately, no preservative system is a total fit for all water-based formulas. Every preservative needs to be evaluated based on the other materials present. Typically a PET is the best thing for evaluating new preservative systems in formulas to ensure efficacy.

For instance, Silver Citrate can be incompatible with cellulose polymers (HEC), some starches, and cationic ingredients.

Gluconolactone causes pH drift downwards-which if you’re not careful will knock you out of your preservative’s effective range. Sodium phytate is similar in that the effectiveness is pH dependent. 

Leucidal liquid is a “mild” antimicrobial at best, and a gamble of a preservative at worst. If you search through the forum for this material you will get much more information. Personally, I don’t use any of these materials because they aren’t the most robust. 

If you have a lot of bug “food” present in the form of various additives in a formula you are going to need to pay close attention to your preservative and also to lowering water activity. These types of formulas are hard to preserve.

[lewhitak]

Agreed on the lactic buffer. I wanted to try it out based on the results of this paper, but ultimately found the triacetin to be more useful for stabilizing the pH after an initial spike. 
This pH spike occurred at RT within two to three days after mixing.

I am very curious how your lactic acid - histidine buffer will go! Personally, I will pay more money for histidine to get a safer and effective buffer system   

[lewhitak]

@Pharma haha! Your database is just getting filled to the brim with ingredient facts is all! 

Personally, the inclusion of a lactic acid/sodium lactate system didn’t give greater stability to the product versus just including the triacetin. There was less drift technically since the starting pH was higher with the buffer system included, but overall I wouldn’t say it did much better. 

I didn’t try it with the ammonia salt of lactic acid, though. Maybe that would help more??

[lewhitak]

Yes! I wish I could remember who in the forum mentioned it, but there was a company who would spray urea solution on starch and then use that in their creams to avoid urea crystallization. 

[lewhitak]

For me, I would put together a general list of what you would like to include and then you build on this list. 

Put together a spreadsheet or something where you can see all of your information at a glance. 

You’ll want to list:
Pricing
Shelf Life
Purported Effect
Usage Levels
IFRA guidelines/Safety/etc (IFRA = Internation Fragrance Association)

You can also include tabs in your spreadsheet to show each version you’ve done and your notes for that version. 

Then, test each individual oil alone on your substrate and write down what you notice. Based on that, put together your first blend and add your fragrances and the PEG according to the supplier’s recommendations and the guidelines from IFRA for leave-on products. 

[lewhitak]

Hello Pharma!
I recently worked on a 25% urea w/w solution and found the only addition that stabilized my pH was triacetin. You could try the triethyl citrate and see if maybe it will modulate the pH in the same way? 

I checked the AMC Advanced Moisture Complex NP and even it has triacetin in it:

Glycerin (and) Aqua (and) Sodium PCA (and) Urea (and) Trehalose (and) Hexylene Glycol (and) Polyquaternium-51 (and) Triacetin (and) Caprylyl Glycol (and) Sodium Hyaluronate 

[lewhitak]

@LincsChemist

That is really helpful, I didn’t think of it from that point of view. Thank you!

[lewhitak]

I did a bit more experimenting and right now the pH is about 6.7. I am assuming we just have too much stearic acid present versus the TEA-stearate at this pH. 

I guess the next move would be adding more TEA, but previously it passed QC at this pH and never looked this thick. 

I wonder why we didn’t get the same TEA-stearate formation as previous batches, even with no formula changes?

The only process change was maybe an increase in shear and possibly heat. We usually homogenize using a Silverson during the initial combining of the oil and water phase, then switch to cool-down mixing with a propeller blade. 

This time, they mixed continuously with a Silverson head too large for the vessel, generated more continuous heat, and allowed to cool by standing not propeller mixing.  

[lewhitak]

@chickenskin 
in situ as in “in place”-like this:
“In situ is a Latin phrase that translates literally to “on site” or “in position.” It can mean “locally”, “on site”, “on the premises”, or “in place” to describe where an event takes place and is used in many different contexts.”

So, we don’t react the TEA and stearic acid to form TEA-stearate and then proceed with an O/W emulsion.

[lewhitak]

Resins that are ambient curing do tend to be softer when the Tg is lower, so you may want to take time to test a higher Tg ingredient and compare. The Tg might be too high if your coating is then brittle.

However, a few things can cause a soft film. If you can, you will likely get better answers by posting your formula.

[lewhitak]

@promises
A white blood cell is about 25 microns, and you need to be smaller than that to replicate the paper. You also have to consider that you not only need a way to mill the ascorbic acid but to also verify your particle size to ensure your process is achieving what you want. The cost of the equipment to do both of these things alone seems as if it would be very high for a personal use serum. 

Maybe you can see if you can find a pre-dispersed vitamin C? Or invest more money to ship encapsulated vitamin C or tetrahexyldecyl ascorbate to your location?

 

[lewhitak]

I mention particle size because this portion of the paper you are referencing is very important in order to replicate some of the results. 

Microfine particles of L-ascorbic acid predominantly
less than 20 microns in size have been reported to penetrate into the dermis from an anhydrous vehicle.26
The objective of this study was to observe the effects
of two anhydrous formulations containing microfine
particles of ascorbic acid less than 5 microns in size on
three known effects of ascorbic acid, neocollagenesis of
collagen types I and III, and cytokeratin production, in
ex vivo human skin. 

At 325 mesh you are approximately 44 microns. You may also get away with adding less than 20% because so little of it will be available for your skin to actually utilize.

[lewhitak]

Formulas with suspended vitamin C have issues with the user being able to feel the gritty vitamin C on their face when applying. You also have nothing to suspend the granules with, so you’ll need to shake your bottle before applying. I would take a look at products like the following:

 The Body Shop Vitamin C Skin Booster
(Ingredients: Cyclopentasiloxane, Dimethicone, Cyclohexasiloxane, Dimethicone Crosspolymer, Synthetic Fluorphlogopite, Mica, HDI/Trimethylol Hexyllactone Crosspolymer, Ascorbic Acid, Bertholletia Excelsa Seed Oil, Tocopherol, Glycerin, Parfum, Ethylhexyl Hydroxystearate, Polysilicone-11, Linalool, Limonene, Silica, Benzyl Benzoate, Citral, Aqua, Hexyl Cinnamal, Myrciaria Dubia Fruit Extract, Citronellol, CI 77891.) 

The Body Shop product uses silicones and other functionals to make for a ‘cushioned’ pleasant application while stabilizing the Ascorbic Acid. You’ll have to research what ingredients you can get from the site you’ve listed and go from there. You’ll also need to mind the grind size of your powders to minimize irritation from application. You can use a spice grinder to blend your powders before adding to the oil. 
The propanediol option is easier, or you can make powder blends to add to your morning serum. 

[lewhitak]

You’ve chosen a difficult formula to work on, and as it stands there are quite a few ways you can take it. Have you done a search through the forum yet?  

[lewhitak]

@Perry I apologize, I missed your response! I am looking for an alternative to dimethicone for use in something like a hand gel for forming a bit of a barrier and for reducing the drag in the formula from using something like vegetable oils.