[Pharma]

Are you sure you added the right amount of TEA? Did you check pH? If not, this would explain why certain batches work and others don’t.

I’d guess that adding 5% polyols as proposed by @UsmanAli will render it a fair bit more sticky compared to 2% PEG 400.

[Pharma]

We’re talking rules of thumb and educated guesses here . Hence, it doesn’t really matter, the more you add the better.

If you want it precise, I refer to mass-% since this is the measure usually used. Density changes with temperature and changes with dilution whereas a kg weighs always 1’000 g.

Vol-% is something traditionally used for alcohol. This, however, is an exception and for most applications completely antiquated. Obsolete and outdated things used for centuries have the tendency to stick around for longer than anyhow useful, just think about imperial units. Even NASA uses these though rounding errors and unit mix-ups caused more than one issue in the past… at least they now also use the metric system and SI units. Guess learning it the hard way means loss of years of work and hundreds of millions of $$ (sometimes literally) going up in flames (CLICK).

[Pharma]

Flash point is the lowest temperature at which a substance can catch fire if ignited.

I hope you don’t heat your formulation over a Bunsen burner .

What plays a role is the boiling point (which is usually well above 70°C. However, in case of fragrances and essential oils, vapour pressure usually dominates and this is less dependent on temperature given that room temp remains the same during production. Hence, time is what may matter most.

Without knowing the chemical structures/names of your fragrances and the overall composition of your formulation makes it impossible to predict chemical stability.

Another probably more likely possibility may be that there is no degradation but you might encounter a ‘solubility issue’. Meaning, the base imparts fixation of certain molecules which changes volatilisation and subsequently fragrance perception/scent. Firmenich (a renowned company producing fragrances and white label perfumes) published some articles showing that the most volatile molecules aren’t necessarily the ones which actually volatilise first and hence, the flavour cascade from top over middle to base notes may not be what you expect or would smell when mixing pure fragrances compared to dissolved/fixed ones.

PS Please use °C. Only some backwood countries have difficulties
with the rational, reliable, easy to use, scientific, linear metric system and still adhere certainly for no more than sentimental reasons to imperial (is that word even allowed to be used in light of #BLM?) units :blush: .

[Pharma]

What do you define as normal conditions?

In order to get the triester in a quantitative amount, a water-free environment or a water-removing condition (e.g. Dean-Stark apparatus) is required. Also, elevated temperatures and/or pressure are mandatory (given enough time, boiling may suffice). By preference, an acid catalyst should be used to bring time down from days/weeks to hours.

This means, dissolving citric acid (which is usually sold as hydrate) in ethanol (which is usually not used in anhydrous form) and just let it sit around at room temperature will remain citric acid dissolved in ethanol for all eternity.

[Pharma]

Short answer is yes, unless it’s surface modified.

[Pharma]

Silicones are gas permeable, they ‘breath’ and that’s why they, although being more hydrophobic than mineral oils, don’t keep moisture sealed in .

Waxes seem like a good candidate but they are solid and hence, you’ll have to  add enough oil to form a continuous flexible film and then it’ll be impossible to really quantify how much TEWL reduction is due to wax, oil, or the combination of the two. In a standard emulsion, wax will likely form tiny crystals/flakes within the carrier and these can’t form a vapour tight film. Waxes may however reduce skin penetration of carrier oils and thereby increase the efficacy of the oils with regard to TEWL reduction.

An exception would be liquid waxes such as jojoba. I don’t know how well that one works…

[Pharma]

Why would there be a difference unless you’re working with an anhydrous product and use 80% v.s. 98% glycerol or try to pre-disperse a gelling agent such as xanthan gum in 80% instead of 99.5%. Even the 98% can be suboptimal for that and hence, using a dry solvent is my preferred choice.

I always take water ‘contamination’ into account and adjust for that. This means, no difference in the end product observed.

Drawback of using >98% is that it’s hygroscopic and dry glycerol becomes <98% at some point. Alas, there’s usually no knowing how wet your glycerol actually is. With hygroscopic powders you’ll see when they turn too wet and sticky but a liquid always remains a liquid.

[Pharma]

What country can be that stupid? Sorry, let me formulate this differently: I knew that certain people working for authorities don’t work for private companies for a reason but THAT stupid?

Unfortunately, there is NO reliable quantitative test for natural oil mixtures
or non-pure natural constituents such as plant extracts unless you provide them with a standard (samples of your raw materials) and all that remains is finding a marker molecule for each of these.

You might just provide them with samples of your used batch of
pure ingredient X and the appropriate HPLC protocols which involve for example SPE separation of free fatty acids and hydrolysis of the esterified fraction followed by derivatisation (silylation or methylation) if they really want to determine unreliable fatty acid profiles. And they should use the right columns and couple the HPLC to a second device such as MS/MS and/or GC.

A different, smarter and leaner strategy is to search for marketed products which contain different fatty acid derivatives and just tell them to suck it up.

Seriously, they’re complete uneducated, useless, stupid nutjobs.

I wonder how they quantify the different gums…

And don’t tell them that sunflower oil contains some of the other ingredients such as water, glycerol, lecithin, potassium, and phosphate or they’re going to kick that out too.

[Pharma]

Forgot to mention: carbonate esters such as Cetiol CC or Cetiol 4 All or ‘natural’ hydrocarbons like undecane/tridecane don’t contain fatty acids.

And diisostearyl malate…

[Pharma]

As an educated guess, 10% ethanol is likely the lower limit.

[Pharma]

I observed that with lecithin too (@helenhelen).

BTW 11% lactic acid does not necessarily keep lactic acid bacteria from growing and it does not keep a bunch of yeast and fungi under control.

[Pharma]

The only protein isolates I know are from whey (they go into my shakes *yummy*)… sure you can use these, as claim ingredients. Whey proteins are hundreds of times larger than hydrolysed proteins and… well, honestly, do the same (=nothing) in a rinse-off formulation. In a leave-on, hydrolysed proteins might serve as humectants.

[Pharma]

I don’t quite understand why you want to reduce fatty acid derivatives (only stearic acid is a free fatty acid, all others aren’t acids but esters) but think that fatty alcohols (derived from fatty acids), lecithin, sunflower seed oil, and polysorbate are okay… anyway, that’s non of my business and neither what you asked for.

Glyceryl Stearate and Stearic Acid -> up cetyl alcohol or replace it with cetearyl or even behenyl alcohol if you want to maintain melting point. I would certainly use a mix of different fatty alcohols. Only using fatty alcohols in a formulation designed as glycerol ester/fatty acid/fatty alcohol combo, this may lead to a lower viscosity, less cushioning, and maybe a less stable liquid crystal network. You could try octyldodecanol instead/in addition, though it will reduce viscosity and result in a quite different feel.

Jojoba Oil -> squalane, that’s the easy one to replace
Shea Butter -> hydrocarbons like vaseline/ozokerite/paraffin, lanolin alcohol aka wool wax alcohol, phytosterols/cholesterol, sphingosine/cerebroside or a polymeric film former to reduce TEWL.

[Pharma]

I’ll keep you in the loop .

[Pharma]

I’m now playing around with triethyl citrate plus a lactic acid - histidine buffer at pH 6-6.1.

From the info I could gather, quite a lot of buffer may be required (that base formulation is with 20% urea) and histidine ain’t the cheapest…

In theory, I should take a strong mineral acid instead of lactic acid but lactate has its perks in skincare.

Finding a weak base as alternative for sodium hydroxide isn’t that easy (okay, it is, but I don’t like these ingredients in my cosmetics) and it seems more reasonable than the ‘traditional’ lactic acid - sodium lactate buffer which will be beyond it’s buffering range and that on the wrong side too. Sure, a weak-weak buffer such as mine ain’t what would commonly recommended… We’ll see if it still works.

[Pharma]

This is an ethical/parenting question…

Is it okay to feed your kids artificially coloured, artificially flavoured, sugar-dripping ice cream high in saturated fatty acids and modified proteins derived from artificial milk, kept in form with artificial gelling agents, boosted to please using artificial sensory and crystallisation modifiers?

If I had kids, they weren’t allowed to wear nail polish nor would I give them such ice cream… at least not on a regular basis.

[Pharma]

How does it smell?

My sodium anisate & sodium levulinate blend from Evonik has only a very faint aroma even if mixed with acid and rubbed pure on skin…

[Pharma]

There is no organism on earth which could grow in these two formulations .

If someone complains about the two ingredients (which aren’t harmless and are the least harmless ones you have there), they will certainly also complain about more or less all your other ingredients too. The solution for these people: just don’t use nail polish :smiley: .

[Pharma]

For industrial production, read the corresponding article on Wikipedia.

[Pharma]

I think that was even me (how embarrassing). :blush:

Triacetin simply didn’t ring any bells. Must be the first sign that my brain’s getting old… but once it was re-attuned to urea stability/degradation rather than everything else, memory came back, at last.

Now I’m having a hard time deciding whether to risk using solely triethyl citrate or including a buffer. Lactic acid/lactate would fit in nicely but it’s buffering range is off…

[Pharma]

That sounds as bad as it may taste… dunno… salt or thymol… meh…

Besides, thymol and other essential oils are oil soluble and need something which brings them into solution and alcohol fits the bill.

[Pharma]

Ah, stabilisation of urea. That might be the reason Evonik seems to use it only in their high % urea base formulations.

A quick search revealed that high % urea tends to recrystallise resulting in a sandpaper feeling and triacetin (buffering through hydrolysis), lactic acid (low pH), or adsorption to polysaccharides help preventing that. Triethyl citrate might actually work as well…

Thanks so much for your inputs, that’s exactly what I needed!

[Pharma]

The one thing I can tell you is that their LOI contains an error (and a blend called LexFeel N5): Diheptyl Succinate, Capryloyl Glycerin/Sebacic Acid Copolymer. There’s a “/”, not a “,” between the words glycerin and sebacic.

Diheptyl succinate is said to feel silicone-like (never tried it myself) and it certainly is a light ester but I have a hard time imagining that only that small amount should change the overall feel of the product.

I’d guess it’s the emulsifier Glyceryl Stearate & PEG-100 Stearate.

But then again, I have a difficult time finding the 1% line… maybe the LOI contains even more errors?

[Pharma]

With the alcohol and glycerol inside, no worries. Without… you’d have to run some tests to see.

There’s a huge difference between chemovars. Example: lemon thyme won’t really work and lavender EO from wild L. angustifolia is more active than lavendine EO from hybrid species.

[Pharma]

Aerosil is also stomach safe. However, it’s not too safe for lungs…

We use it for example for capsules and sometimes also pharmaceutical creams.