[Pharma]

Eh? If you could explain how it’s done in such a good way that you would pass as expert before your own eyes, why don’t you yourself write the article?

Retinol is a chemical compound and hence, you don’t necessarily have to be a retinol specialist but rather a pharmacist or chemist to know from common knowledge what it takes.

No, I don’t know the cosmetic laws of every single country but I know some (of the better regulated one) and I know the difference between cosmetics and pharmaceuticals: The latter have regulations regarding stability and degradation.

As long as this is an open public forum, I’m commenting on whatever I’d like to comment.

Or do you simply need someone with intimidating enough credentials so nobody will double check when he/she puts his/her name under your opinion so you can discredit competition in order to boost sales of your own product? That’s an honest question for an honest ansewr, not an offense or an insult (I have the impression you do feel that I’m doing exactly that but I’m not).

[Pharma]

I had a gread day, I know that retinol can be what you call ‘stabilitzed’ (turns out that your initial post is misleading because you’ve been asking for ‘to write an opinion regarding the lack of retinol stabilizing ingredients’), and I’m not US based .

You’re referring to cosmetics, not drugs and (probably with the exception of Japan where some products are quasi-drugs) hence, degradation isn’t an issue as long as the degradation product doesn’t do any harm (which is unknown but assumed non-problematic due to a don’t care mentality in case of retinol).

Accountability is in the hands of the manufacturer and, quite seriously, most don’t care too much because they know that it’s virtually impossible to prove that a degradation product of a cosmetic ingredient caused harm (humanity usually learns the hard way some decades of ‘don’t worry, this is absolutely safe’ later).

You’re quite the cosmetics person because you ask a chemist for an opinion instead of using facts and publishing your data showing how it’s done (or how not to do it).

[Pharma]

Just to understand you correctly:

You’re looking for a retinol expert (= a beauty expert, dermatologist, or plastic surgeon) who studied chemistry (not cosmetic chemistry but real chemistry) who writes an article on some commercial retinol products which do not contain ingredients to protect retinol from degradation (and wherein only a clairvoyant knows wheter or not and if, how badly, retinol actually degrades)… WTF!

What you need is a psychologist to explain why some people give a s#|+ whether or not their cosmetic ingredients degrade, a layer who explains why said people don’t have to because they can’t be sued neither for negligence nor ignorance, and a marketing person to elaborate on how easy it is to sell dirt for gold .

[Pharma]

Yes.

[Pharma]

Several polyglyceryl esters are used for that purpose (examples are PG-4 oleate and caprate or PG-3 stearate). They aren’t ‘natural’ depending on definition but they can be made from 100% renewable feedstock e.g. glycerol and fatty acids and are usually allowed by the labels in question.

[Pharma]

A: Montanov 202 and glyceryl stearate SE have a higher melting/processing temperature than the other ones (~10°C higher). Generally, 70°C is on the lower end for all of them. Try 80°C.

B: Montanov 202 is also different insofar as it can handle higher amounts of oils or rather is meant to be used with considerably higher oil phases.

C: The four emulsifiers all result in lamellar gel networks rather than micellar emulsions; hence, they may not take too high too long shear mixing (especially under the ‘gelling’ temperature) very well.

D : Because of point C, all these emulsions will ‘ripen/harden’ over the next few hours to days. Give them some time to fully attain their final viscosity. Cooling rate can also be part of the difference (M 202, because of point A, doesn’t do well when cooled too fast and can’t ripen in the worst case).

[Pharma]

Weird. Some resources list the INCI the other way round. Anyway, it can only be 40-70% and 30-60%, respectively, unless there’s 10% nondeclared stuff inside too (such as moisture or magic).

Based on the saponification value of Kostol Natural E Wax N° 414, I calculate 60-80% PG-3 stearate. Based on theory of lamellar networks and the proportion Montanovs contain, PG-3 stearate content would be in the 20-30% range (that would also be my guess).

And now you know as much as before.

[Pharma]

Isododecane is likely safer than the essential oils you’re going to diffuse with it .

Isododecane is completely inert (it doesn’t do anything, doesn’t react with anything, and leaves your body unchanged), think volatile vaseline but biodegradable.

[Pharma]

Abdullah said:

…

All in mol ratio
1. What is the best ratio for maximum emulsion stability?
2. What is the best ratio for maximum conditioning in hair conditioner?
3. Can liquid emulsifier like polyglyceryl-4 laurate+ GMS or fatty alcohol make LGN products?
4. Can SLS or SLES+ GMS or fatty alcohol make LGN product?
5. If GMS is used as LGN promotor, what should be counted as it’s molecular weight?
For example

GMS is 358.57g/mol(google search

GMS with 40% mono, 50% di & 5% tri is 500.512g/mol (my calculation)

GMS with 90% is 385.215 g/mol(my calculation)

So if i am using GMS with 40% mono, should i count it as 500.512 g/mol or 358.57 g/mol?

1. As said, the optimal ratio of a given formulation (if said formulation even has one) depends on the formulation itself and can not be calculated.

2. See N° 1.

3. AFAIK laurate is the short end of hydrocarbon chains which still forms liquid crystals. However, the low melting point becomes an issue and may result in very fluidic liquid crystals.

4. Yes

5. Yes (is’t still an estimate because all the other cosmetic ingredients are oft not pure and have only average MW but that’s usually close enough).

[Pharma]

@BrendaM As one nearly always does in developing cosmetics: trial and error.

Experimental setup depens on what you have, what you want, and how much time and effort you are willing to invest. Basically, you start with a formulation low in LGN promotor and subsequently add more until you hit the feel and stability you heart desires (if you don’t, switch the basic formulation and start anew).

[Pharma]

@zetein

Very well observed. Olivem 1000 is a gread example of an exception wherein seemingly everything contradicts the possibility of an LGN. I honestly don’t know the true answer and was wondering too. Looks like there are two kinds of LGNs: the one people usually refer to is the α-gel network (a liquid crystall) which follows the mentioned rules and there are non-α-gel networks such as those formed for example by the branched-chain fatty alcohol 2-octyldodecanol which are said to be non-crystalline (couldn’t find any reliable information). Neither could I find anything in literature which would shed any helpful insight in the matter of Olivem 1000. Cetearyl olivate and sorbitan olivate are very similar to one another and are therefore likely to assemble (well, they have to or it wouldn’t work so nicely). Cetearyl olivate is a liquid ester wax similar to jojoba oil which doesn’t have an HLB but an required HLB value and sorbitan olivate aka Span 80 which is a very low HLB emulsifier… My guess is that they form an ‘inverse’ lamellar phase. If you invert lamellar phases, you end up with another lamellar phase… basically, both are the same and by definition, both are liquid crystals. How one would obtain such a structure without the crystallinity… I honestly don’t know but it does seem possible based on reason and it also seems possible that this combo actually works though it’s 100% against the rules. Obviously, the HLB system in this case is as useless as it is with all LGNs.

Regarding the other Q: TEA stearate = ‘high HLB’ emulsifier and stearic acid = LGN promotor. Totally follows the rules.

[Pharma]

The C16/18 blend has unique properties (probably the reason why it’s so abundant in nature) which makes it (until proven differently) the most stable and versatile of all. Besides, it’s the oldest one, has the most experience/proven formulations and longest tradition, it’s now also the one where science found proof for its greatness, and then there’s good old $: best availability, broadest choice of producers, biggest production plants, easiest synthesis and so on and so forth.

[Pharma]

There are other factors such as patentability, marketability, hypes, ease of sourcing and so on and so forth. Many things which have been published never made it for sometimes obscure reasons whilst others just popped up decades later as ‘new’ inventions. Sometimes, the time of publication just wasn’t right. (BTW too lazy to read the article, sorry)

[Pharma]

Basically all conditioners and many other cosmetic products which contain considerable amounts of fatty alcohols, free fatty acids, glyceryl monoesters of fatty acids, fatty acid-2-lactylates, and other similar derivatives are highly likely to contain LGNs.

The % given are nearly always weight-%, however, what really counts is the mol-ratio (= number of molecules) of surfactant (or emulsifier, nearly no matter wheter anionic, cationic, or nonionic, as long as the hydrophilic head group is rather small) to ‘LGN promotor’. Anything from 6:1 to 1:6 (whole numbers preferred) is possible, high viscosity tends to be at a ratio of (approximately) 1:3 to 1:6. Ratios from 1:1 to 1:6 tend to be mostly LGN whilst ratios between 6:1 and 1:1 will result in mixed type emulsions (part micellar system, part LGN). Ratios of 1:>6 will result in a third phase composed of LGN promoter which doesn’t do much good nor feel that great, simply put, it’s blobs of fatty alcohol floating in the soup.

BTW LGNs are a type of ’emulsion’ which is not compatible with the HLB system and can not be calculated/predicted using the HLB system. Fatty alcohols allegedly have HLB values although these are only apparent values. They are not emulsifiers and therefore can’t have HLB values (neither are they oils/fats and therefore can’t have required HLB values either). Fatty alcohols are not considered emulsifiers nor co-emulsifiers in the proper sense, they are a species on their own (= LGN promotors or so). Glyceryl monoesters and other LGN promotor on the other hand can be emulsifiers/co-emulsifiers and can have HLB or HLD values.

The mention of high and low HLB emulsifiers is hence incorrect. Correct would be emulsifier (doesn’t matter which HLB) plus LGN promotor at a correct molecular ratio. Depending on several factors (which aren’t calculable by conventional means), the ‘best’ ratio of the two depends on both partners (including head and tail), not on any hydrophilic-lipophilic difference/balance.

Where the article is right, anything which intercalates with lamellar crystalline structures can decrease viscosity. This concerns mostly unsaturated and branched hydrocarbon chains on either, the emulsifiers and the LGN promotors as well as some emollients (e.g. ester oils).

[Pharma]

Products with benzoyl peroxide need to be left on for at least 1-2 minutes, other rinse-off products for example with fungicides require up to 5 minutes (of freezing you butt off in the showers)…

[Pharma]

In a rinse-off product, it doesn’t do any job other than marketing. Whatever you do, it will simply be flushed down the drain.

[Pharma]

@skininthegame Any update regarding your trial with potassium azeloyl diglycinate?

[Pharma]

The two are synonyms for the same ingredient. Te former is the term used in pharmaceuticals whilst the latter is INCI nomenclature.

[Pharma]

ROFLMAO! Good one!

I hear it’s a great pet shampoo, too. Especially for feral Hawaiian pigs :smiley: .

[Pharma]

You don’t have triglycerides (at least, you should have <10% if you’re ‘super-fatting’) but mostly fatty acid sodium salts. By instinct, I would expect glycerol to remain in the water phase upon salting out, given that glycerol isn’t an electrolyte (it’s not dissolved in water but mixed with water, so you could say that water is mixed with glycerol as well). According to a quick Google search, this should be true.

However, you seem to have no glycerol and so I wonder: Do you add too much salt? After all, fatty acid sodium salts are amphiphilic and especially sodium salts of unsaturated and/or medium chain fatty acids dissolve nicely in glycerol. And from gylcerol soap we know already that glycerol dissolves well in soap…

An alternative approach to salting out can be boiling as has been traditionally done. Sodium soap is insoluble in hot water and will floculate and float to the top. I’ve tried that myself and ended up with fairly clean sodium soap and a glycerol-water-sodium hydroxide blend.

[Pharma]

You add salt to separate soap from water? Well, that likely explains it. The effect you get is called ‘salting out’; it means that saturating water with salt reduces solubilities of other solutes and pushes these out especially if there’s a second phase wherein those solutes are soluble. In your case, the second phase is soap and soap dissolves glycerol.

[Pharma]

I would first evaporate water. This can be done at a water bath temperature of just 60°C and a standard vacuum pump (vacuum in the one digit mbar range; if I calculate it right, -700 mmHg equals 70 mbar… that’s just good enough for volatile solvents).

You could as well just boil water off at atmospheric pressure.

Because glycerol is hygroscopic, you might not obtain totally dry glycerol (but you can dry it for example with anhydrous magnesium sulfate).

Afterwards, evaporate glycerol off. There you’d likely have to heat up to 200°C or even more depending on your vacuum. Given that you don’t care for the solids, a charred residue isn’t too much of a problem (good luck with cleaning the flask, though :smiley: ) and you might want to re-distill your glycerol.

A cleaner way would be to separate glycerol/water from residues by extracting with alcohol (which you can easily recycle with your rotary evaporator) first and then ‘dry’ your glycerol by evaporating first the water off and then glycerol. If you werer to add alcohol (ethanol or methanol) directly to the reaction mixture (before or after saponification doesn’t matter as long as you don’t heat above the alsohol’s boiling point), you could use a lot less water.

As a last thought: Maybe your saponification didn’t work and you don’t have glycerol at all? There’s no way you’ve boiled off glycerol at 110°C at atmospheric pressure but the 110°C boiling temperature indicates that you don’t have pure water but a solution (question is, is the boiling point increase caused by glycerol or salts). Not to speak that you would have noticed if you didn’t saponify your oil LoL.

[Pharma]

Glycerol and water don’t form azeotropes. Besides, it is extremely difficult to evaporate glycerol under vacuum unless you happen to have a molecular distillary. Water on the other hand is easily removed.

However, you’ll only end up with 80-98% glycerol depending on the simplicity of the apparatus and the number of distillation steps.

My guess is that you’re doing something wrong. BTW Using less water in the reaction mixture would already result in a more concentrated form of glycerol.

There’s tons of papers describing the How To of saponification and glycerol purification .

[Pharma]

@evchem2

A: Correct, it’s the benzyl ring which dictates this.

B: Stop using/thinking HLB. It’s a system which is only suitable for pure PEG-based emulsifiers in very simple mixtures. Start using HLD.

C: True, it has a ‘required HLB’ or, in HLD language, an EACN and not a Cc value.

But, as said in point A, alkyl benzoates behave differently to standard oils. For those who like the HLB system more, benzyl rings behave similar to PPG moieties as found in extended surfactants (obviously, alkyl benzoates would correspond to one without the PEG end chain). Back in the day, you could find the benzyl ring in nonylphenol surfactants too and it was that aromatic ring which gave it the extra kick (and the toxicity which led to its ban). Alkyl benzoate are like such an ‘interface-active’ surfactant but with a hydrophilic head group which tends to zero in lenght = HLB becomes negative. I know, it’s counterintuitive and true surfactancy is obviously completely lost.

[Pharma]

So, you mean, they take spoiled oil, rebrand it as ‘fermented’ and sell it for more $$? I’m at a lack of words…