[Doreen]

I bet the vitamin E in the capsules of 400 I.U. is the acetate form of tocopherol, which doesn’t have antioxidant activity (at least not for the product, skin may be able to convert it, but to inhibit rancidity of the product, it’s useless).

Clays are notoriously hard to preserve. You can’t just pick a preservative and hope it will be ok, you will need to perform tests to be absolutely sure your product is safe to be used by consumers.

[Doreen]

I totally agree with Perry.
Plus they’re hard to preserve.

[Doreen]

Simply said: the higher the vapour pressure and the lower the boiling point, the more volatile the substance is.
For example chloromethane (although a gas at room temp, wrong example maybe) has a vapour pressure of 490.000 Pa (20°C) and a boiling point of -24.2°C.

Edit: typo

[Doreen]

@Cst4Ms4Tmps4
Not water pressure, but vapour pressure. You can read its exact definition in this link, it’s an indication of a liquid’s evaporation rate. The ‘Pa’ stands for ‘Pascal’, this is a unit of pressure (one newton per square meter). Vapour pressure is sometimes also expressed in other units, like millimeters of mercury (mmHg), or kilopascal (kPa=1000 Pa).

Do you mean 31°C ambient temperature outside or inside your house, where the cyclopentasiloxane is stored?

[Doreen]

@Cst4Ms4Tmps4
Cyclopentasiloxane doesn’t need airless packaging on itself, neither the pure product nor if used in cosmetics, it’s not as extremely volatile as you think it is. With a boiling point of 210ºC and vapour pressure of 33.2 Pa it’s not that bad. The amount that evaporates in your product, when stored at room temperature, really is negligible.

[Doreen]

I’m about to try Aristoflex Silk, it’s said to have great electrolyte tolerance and sensorials. I hope it’s even less tacky than Sepimax Zen.

Re: Ultrez 30. It has a reasonable tolerance, you just shouldn’t add high levels of electrolytes. I never have problems with it.
No polymer is totally electrolyte resistant of course.

I tried to upload some documents here (regarding carbomers etc) but the file sizes are too large.

[Doreen]

@insan
https://chemistscorner.com/cosmeticsciencetalk/discussion/137/need-formulating-services-here-are-some-contacts#latest

[Doreen]

Welcome!
I’m not sure how exactly it is synthesized, but I don’t think you can simply create it just like that and expect the same results. 
Isn’t it possible for you to keep on buying the Olivem 1000 instead?

[Doreen]

@MarkBroussard
Ok, thanks! I was about to buy Sepimax Zen from The Formulary, and I saw they now sell GDL too. I will purchase that as well then! ☺

[Doreen]

@MarkBroussard
What is your opinion on GDL as chelating agent?

[Doreen]

@Belassi
The only glassware I bought there are volumetric flasks, glass stirring rods and watch glasses. The volumetric flasks arrived in good condition and seem less fragile than I expected them to be. But incomparable to brands like Pyrex or Duran of course, which are top notch.

[Doreen]

@VitalikButerin
And many times there aren’t even shipping costs (AliExpress).
The only thing you need is patience. It takes about a month before you receive the item (sometimes 2 months, other times only a week).
One advice: never buy glassware there. There’s a 50/50 chance to either receive the items in perfect condition or get them in a thousand pieces (it’s easy to get a refund though). This really depends on the individual seller (some are way more thorough and careful than others) and the value of the item that you purchase (and the ordered quantity). They won’t put a sturdy box around one or two watch glasses for example.

[Doreen]

I have three from AliExpress.
One has 0,001 gram accuracy with a 50 gram max (± $20), 0,01 gram accuracy with 200 gram max (± $5) and 0,1 gram accuracy with 2 kilogram max ($7).
The first (0,001 gram) can be adjusted (levelled) and calibrated and came with a calibration weight. Other 2 can also be calibrated, but didn’t came with calibration weights.

I’m very pleased with the scales.

[Doreen]

UPDATE

I’ve been thinking it over and the probable reason for the ammonia smell was that I put too much drops of NaOH 18% solution to my emulsion, which I think raised the pH way too high (maybe around 10 or even higher, if only I had some left to test). Before adding the drops the pH must have already been above 5 so I needed really a tiny tiny bit. And I remember using several drops right after eachother in one time.

I’ve been making an exfoliating toner for a few years now, this toner contains both allantoin and betaine and I raise the pH with sodium hydroxide at a high temperature (65C) without problems. The difference between this toner and the forementioned emulsion is the pH. The toner, before adding the NaOH, is around pH 2.8. After adding NaOH it is around 3.8, so still acidic.
To raise the pH from 2.8 to 3.8 with NaOH 18%, quite a bit is needed (around 2%). Because I make the toner quite often (way more often than emulsions that I neutralize with NaOH), I think it was force of habit using a larger quantity of several drops in one time rather than a single tiny drop first and measure the pH before going any further.

@Bill_Toge
I hope you don’t mind me asking one more question here.
You mentioned TEA and AMP not being able to hydrolyze amides as these are non-nucleophilic.
But if I used TEA or AMP and raised the pH to e.g.10 or higher, wouldn’t there be an alkaline hydrolysis anyway?
(The toner that I mention in this post as example, is the same as the one that turned into a gel yesterday. I raise the pH to at least 3 while it is still hot, because I’ve had the SA precipitate when I waited too long in the cool down without raising the pH. When it’s at room temperature I raise it further to around 3.8.)

[Doreen]

@Bill_Toge
The strange thing is that I always use dipotassium glycyrrhizate in this toner, with 2% salicylic acid, this is the first time that it has happened. It’s the first time that I use hibiscus extract though (the other extracts that are mentioned in the LOI come from Prodhyactif Softening, what I’ve used several times before in this toner). I’ve been making it for around 2 years now like this without problems. Weird, right?
Paula’s Choice also has this particular licorice salt in one of her 2% SA toners by the way (pH 3.2!).

Edit: I checked again today, the pH was still 3.74. I put some high shear on the gel to see what would happen and the appearance became milky, like an emulsion. I put it aside for a while, later I checked again and some of the substances (maybe SA or allantoin, or both) had precipitated and formed a cloudy layer on the rest of the liquid which was clear.

[Doreen]

@Microformulation
Wow, thanks a lot!

[Doreen]

@Perry
I tried to attach documents here (and below) but it doesn’t work (file sizes are not too large or anything).
Could you help me with this? Thanks in advance!

[Doreen]

You’re welcome!

I indeed combined ascorbyl tetraisopalmitate with tocopherol, as they work synergistically against oxidation.
I’ve been searching in supplier’s documents, but couldn’t really find much regarding stability (recommended pH etc), only that it’s heat stable (I put it in the cool down phase however to be on te safe side).
I used it in moisturizers with a pH between 5 and 6 and put it in airless dispensers.
I really prefer suppliers who give extensive information about their products, like Evonik and Dr. Straetmans for example!

What did you read in the reports about the instability?

Edit: I almost forgot. My ascorbyl tetraisopalmitate was from Nikkol. (Nikkol VC-IP) I have a few documents I’ll share here, maybe these can be helpful somehow.

[Doreen]

Dipotassium glycyrrhizate could also be used as anti-acne active, it’s said to have sebum regulating properties. I like to use it as skin soothing active. It can be used in low pH products (Paula’s Choice uses it in pH 3.2 AHA/BHA exfoliants).

Edit: btw I wouldn’t use niacinamide at a too low pH because it might hydrolyze to niacin (skin irritant) over time.

[Doreen]

Well, compared to the products of Paula’s Choice that contain it, it’s not even that bad. Take PC’s Resist Intensive Wrinkel Repair serum for instance, the Ascorbyl Tetraisopalmitate is well below the 1% line and 1 oz (30 ml) costs $42.

What I like about Uncover is that they’re transparant about how much % of actives their products contain. Plus they don’t sell nonsense like eye creams or special anti wrinkle products etc. Plus the sunscreens are non-profit (Suncover).

About the cyclo D5. It must be ≥5%. The 1% line must be between glyceryl stearate and the dipotassium glycyrrhizate. So then it’s
≥1% GMS (± 3%?)
≤1% PEG-75 Stearate
≤1% Ceteth-20
≤1% Steareth-20
along with cetyl (±2%) and cetearyl (≤1%) alcohol  as co-emulsifiers emulsifying the cyclo D5, the propylheptyl caprylate (±2-3%) in the oil phase.
(I don’t know how long and high cyclo D5 can be heated before too much evaporizes. It’s too much to put in the cool down phase I think.)

[Doreen]

Tetrahexyldecyl Ascorbate is a synonym for Ascorbyl Tetraisopalmitate.
A very popular brand in the country where I live (Uncover by Jetske Ultee) uses 5% of it in their moisturizers (+ 5% niacinamide), packed in an airless pump. They sell it for 50 euros (50 ml), which is about 56 dollars (USD). Amazing, right? It’s one of the best brands that I know (along with Paula’s Choice).

This is a LOI of their normal to oily skin moisturizer (which is also 56 USD for 50 ml):
Aqua, Cyclopentasiloxane, Ascorbyl Tetraisopalmitate, Niacinamide, Glycerin, Propylheptyl Caprylate, Cetyl Alcohol, Glyceryl Stearate, Dipotassium Glycyrrhizate, Sodium PCA, PEG-75 Stearate, Caprylyl Glycol, Cetearyl Alcohol, Tocopherol, Sodium Hyaluronate, Evodia Rutaecarpa Fruit Extract, Ergothioneine, Ceteth-20, Steareth-20, p-Anisic Acid, Xanthan Gum, Lactic Acid

[Doreen]

Perry said:

Just use parabens. They will be the least problematic and they have decades of demonstrated proof that they work. 

I totally agree.
I suggested Liquid Germall Plus and Germaben II in another discussion to @Thota, but maybe their customers don’t want parabens and/or formaldehyde releasers?
I myself have a very sensitive skin and I too layer several leave on skincare products and use parabens all the time (and formaldehyde releasers). My skin tolerates it very well, no problems at all. The only preservatives I very obviously react to are sorbates (with skin flushing) from concentrations of about 0,12% and higher.

[Doreen]

@Thota
It seems that sodium levulinate and sodium anisate (Dermosoft 1388, Dr. Straetmans) should also work well at a pH of 6.45. I read it in this article, written by a cosmetic chemist. Very interesting. Apparently these salts don’t even need to convert to their acid forms to be active!

Dermosoft OMP from Dr. Straetmans (Methylpropanediol, Caprylyl Glycol, Phenylpropanol) could also be an option. It’s pH independent.

Good luck!

Edit: Dermosoft 688 (p-anisic acid) works from pH 4- 6.5 according to manufacturers data.

[Doreen]

@”Dr Catherine Pratt”
It’s the Sodium Ascorbyl Phosphate that is alkaline, and I’m not surprised that a 5% solution will make a pH of around 9. 
I recently formulated a moisturizer with 3% SAP and I thought I would need something like sodium lactate to raise the pH some more to 6.5, but I even needed to lower the pH (it was 8.12).

@Thota
I think the discoloration you mention below pH 6 is actually the SAP oxidizing. 
You wanted to change preservatives because of skin reactions due to phenoxyethanol, right? How about Liquid Germall Plus? Or Germaben II?

@Waleed636
I used lactic acid to lower the pH a bit.

[Doreen]

@MarkBroussard said:

Dura Quench from Croda. You can purchase small quantities from MakingCosmetics.com

Cetyl Alcohol (and) Isostearyl Isostearate (and) Potassium Cetyl Phosphate (and) Cetyl Stearate (and) Stearic Acid

I see it contains isostearyl isostearate, George Deckner from UL Prospector also recommends this, for reducing TEWL. 
(“Emollients (5-15%): historically most hand and body lotion formulations used Petrolatum due to its ability to reduce TEWL or skin moisture loss. I recommend using emollients which can positively impact the crystallinity of epidermal lipids and have a good skin feel. These include:

• Isopropyl Isostearate for improved hydration
• Isostearyl Isostearate for reduced TEWL
• C12-13 Lactate for stimulating epidermal lipids production and hydration” )

Source (also contains more tips regarding moisturizers by George Deckner).