[Pharma]

@Abdullah I found some publications on PubMed and ScienceDirect. I didn’t safe them… sorry!

[Pharma]

@PhilGeis For example if you have close to 100% organic ingredients… which come in a non-recyclable plastic bottle… ough… I give up!

[Pharma]

Ah… okay… but you mention there 0.05% and in the LOI 0.625%???

Anyway, that blend is meant to create lamellar structures, not micellar ones. Hence, you can’t just downscale it proportionally when using less oil phase. You have to use a certain quantity to get a stable structure. I’m also not convinced that this blend is suitable for such a small oil phase.

As mentioned by @Abdullah, BTMS 50 is cationic (and would also create lamellar structures) whilst SSL can be anionic (we don’t know the pH or your formulation) and hence, at the wrong proportion the two make an emulsion highly unstable. At the right one, the ‘incompatibility’ can actually increase stability… remains to be tested (especially because you don’t know how much of the two emulsifiers are actually in the two blends). Still, if you want to combine BTMS 50 with a second emulsifying wax, go for a nonionic one. Again, the overall % is low and instead of increasing it, me personally, would go with a different type of emulsifier for such a small oil phase.

[Pharma]

So you have 3/4 organic (certified organic?) and 1/4 synthetic (petrochemistry?)? Why?

I mean, I totally understand if you don’t use 100% organic but why not try and use ingredients from renewable feedstock instead of synthetics? Or the other way round: If you like synthetics (which is also okay), why do you use expensive and unpurified organic stuff instead of refined ingredients?

To me, claiming 75% organic ingredients is like greenwashing. It’s done very often in the EU, sometimes to the point where you think you buy organic when only a part of it really is… And claiming 3/4 natural origin is meagre, you may as well not mention it. Maybe just put an * behind the organic ingredients without mentioning %? In the end, the decision depends on marketing experience and your costomer profile… two subjects I can’t help you with.

[Pharma]

What is the INCI of Emulsifying Blend? Sounds like it could be anything.

[Pharma]

@Perry Do you have any idea how that stupid regulation came to existance? I mean, there are hundreds of more important things which could/should be regulated in cosmetics and that regulation isn’t even protecting customers.

And how would one prove (or disprove) the part you put in bold letters? From a practical point of view (no one is likely to double-check), one could simply add traces of an approved colour and use a plant extract or similar to do the real job instead…

A bit OT: choline salts and their esters are currently prohibited in cosmetics for bogus reasons (dating back nearly 50 years, if I’m not mistaken) whilst similar compounds, some of which totally artificial and poorly tested, let alone GRAS food supplements, are seemingly okay to be added.

Like with so many things, legal decisions are too often biased by lobbying and political ploys (by people who have not the slightest education or knowledge thereof) than based on scientific and logical reasoning.

[Pharma]

grapefruit22 said:

Can lysolecithin darken at elevated temperatures similar to lecithin?

Yes, I’m afraid so . Hydrogenated lecithin is more stable but still on the fragile side of things.

Personally, I don’t like heat testing too much unless your product acutally experiences such temperatures during its life. Every ‘speed test’ used to predict long term stability has to be evaluated for its usefulness for any given product. Emulsion stability (physical integrity of the mixed water-oil system) at elevated temperatures is okay to use as predictive parameter whilst chemical stability might indicate degradation although there might not be any. Also, colour (pigment formation) often shows no linear correlation with degradation.

As antoxidants use ascorbic acid or ascorbyl palmitate (depending on what you want to protect) and tocopherol. Rosemary extracts can be a good addition (a rosmarinic acid rich version would be best in conjunction with ascorbic acid whilst carnosic acid/carnosol rich extracts would be my partner of choice for ascorbyl palmitate). If it’s not an issue with your philosophy, dithionite or metabisulfite can help as well (either as substitute for ascorbic acid or in addition to it).

[Pharma]

If the irritation is just during the first few seconds, it might be pH or osmolarity related. No ‘classical anti-irritation ingredient’ will help here, not even polidocanol or lidocaine because they all don’t act fast enough.

[Pharma]

Graillotion said:

… what about just plain propanediol…(not the esters) where does it fall into this discussion.

In the OT section? It’s a diol, not a glycol. Mode of action is unknown. As an educated guess, propanediol as well as propylene glycol and methylpropanediol might interfere with glycerin metabolism (and, at high enough %, reduce water activity and exhibit solvent-like properties which messes with all kinds of biological processes).

[Pharma]

BTW two more things:

1: I was a bit astonished that propanediol esters weren’t used as preservatives… turns out that Symrise offers one: Crinipan PMC. I’m always a tad too late as it seems (my idea predates their patent from 2019 but how do I prove that? LoL!). Notably, propylene glycol esters are also offered as preservatives by Abitec: Capmul 907P and 908P.

2: Glycinates and lactylates of medium chain fatty acids also exhibit antimicrobial properties. Forgot to mention these derivatives earlier.

[Pharma]

It’s an untypical fatty acid for two reasons: It has an odd-numbered chain and a terminal double bond which happens to be approximately in the middle of an ordinary fatty acid chain. The unsaturation at that position is the most effective to affect membrane integrity/crystallinity (and the reason why nature loves oleic acid). Apart from that, C11 (C12 being more theoretically active but limited by its poor solubility and resulting micelle formation) and the lower melting point due to unsaturation is just hitting the sweet spot a tad better than more frequently found medium chain fatty acids (even-numbered and saturated) and their derivatives.

Monolaurin (glyceol monolaurate) is equally, if not even more, effective (hard to tell due a lack of comparative studies) but somehow never really made it into the world of preservatives. It doesn’t have that off-putting odour of undecylenic acid but alas, has considerable emulsifying properties which makes it a bit unpredictable in emulsions and that isn’t great if it’s not added as emulsifier. On the other hand, it became a hyped food supplement. Sometimes, a molecule needs luck and coincidence more than evidence and scientific publications to become appreciated for a certain use.

[Pharma]

As @PhilGeis pointed out, cell membrane disruption is just an educated guess. If something exhibits a pharmacological effect, there has to be a reason… if you can’t prove how then you go with what you have even if it means speculating. If there were a single way to disrupt membranes, then there would be no point in blending and then there would be less differences between all those preservatives which allegedly disrupt membranes. Also, soap does the same and emulsifiers are supposed to do the same as well… how comes they don’t exhibit an equally good preservation?

As said, the 10 (plus minus 2) carbon chain length is just something which happens to be close to the sweet spot for many similar chemicals and many different microbes (with as many exceptions).

I do think that due all those smaller and larger differences, using blends is ehh.. maybe not more efficient but safer (less chances for exceptions slipping through). Also, longer chains mean higher chance that those preservatives mess with the emulsifiers and viscosity whilst shorter chains come with humectant properties and the like. If you want to blend ingredients, maybe blend different chemical structures, say, a glycol with a glyceryl ester?

@Graillotion You’re correct. The basic understanding is that ‘softening up’ membranes makes the job of ‘real’ preservatives easier and more efficient. Hence the recommendation to not rely solely on membrane destabilising preservatives aka boosters. However, dosage makes the poison and enough of more or less anything can kill. With traditional preservatives, you want to keep tham as low as needed whilst ‘newer’ multifunctional ones may be used at higher levels not for preservation but solely for feel and all that fancy schmancy fluff. Which also means that the choice which boosters to combine might as well be based on ‘secondary’ effects than a chain length which hasn’t much to say unless you prove that it works best in specific case A (and possibly fails in case .

[Pharma]

Chamazulene, the blue pigment in blue tansy EO, is fairly unstable and will most likely contribute to colour change.

Are the oils and butter highly refined or unadulterated/vergine?

Once one ingredient starts oxidising there’s a fair chance that it sets off an avalanche (my guess is that lecithin will be part of it). From personal experience, lecithin browns faster than highly unsaturated oils at elevated temperatures.

[Pharma]

Antimicrobial activity of fatty acids and their derivatives (e.g. glycols and more precisely 1,2-diols, fatty alcohols, sphingosines, monoglyceryl and methyl esters, glyceryl ethers) increases with chain length but, as @Formulator mentioned, water solubility drops. Hence, there is an optimum around C10 (C8-C12) depending on the derivative. The main antimicrobial effect at least of medium chain fatty acid derivatives is by destabilising membranes and seems to be common with all derivatives though secondary effects can not be excluded and are likely the reason why different derivatives have different antimicrobial spectra with regard to chain length. That’s also why there is not a single graph but actually a bunch of publications… a small and by far not comprehensive bunch, to be honest.

[Pharma]

Perry said:

…And are they going to count genetically modified yeast or bacteria as “natural”?
…I don’t see how you can make a natural surfactant-containing cleanser.

Sometimes they are genetically modified but more often a slightly different approach is prefered: biotechnology. Not that there would be any ethical or functional difference IMHO but biotech isn’t GMO.

The knowledge is around for about two decades and industry is finally picking up pace with larger scale porduction of sophorolipids and rhamnolipids: EXAPLE 1 and EXAMPLE 2 (both are from Evonik… I think they bought up the original French inventers).

[Pharma]

The ‘coc’ part (the fatty acid) is obtained from coconut oil (should be but may also come from palm kernel oil) whilst the amidopropylbetaine part is pure petrochemistry. Noteworthy, CPAB is not synthesised using betaine and even if, betaine aka trimethylglycine as we use it in cosmetics and as food supplement is neither ‘natural’ nor is it obtained from the isolated amino acid glycine but is 100% synthetic (the amino acid glycine is usually synthetic, too). Bon appetit…

[Pharma]

Mix without making that ‘votrex’.

Dimethicone is used to prevent soaping during application, not to prevent air incorporation due to unappropriate mixing techniques.

Besides that, you might want to try with a lowre amount of base and a thickener in the water phase to maintain an equal viscosity.

[Pharma]

@Graillotion Poetic! Couldn’t have explained it better 😉 .

My go-to fulcrum for such cascades is also isoamyl laurate. Coco caprylate is nearly as nice but a tad richer (I sometimes use it as IL surrogate when expiration date happens) and I’m starting to appreciate myristyl myristate more every time I’m using it.

Cetiole Ultimate (= C11 and 13 alkane) feels absolutely terrible when used neat, like benzine (C13-15 alkanes, isododecane and other volatile hydrocarbons are likely quite similar). In a blend however…

I admit, I never worked with C12-15 benzoate and am wait for a malate ester and an alkyl lactate to arrive. They might be worth trying (however, they are quite ‘synthetic’). Maybe someone else can chime in?

Regarding non-naturals: D5 feels really nice in blends but, like other silicones, PEG derivatives, and other ‘chemicals’, is against my philosophy. I’m an agnostic scientist, so, yea, I obviously have those in stock and paly with them, one simply can’t replace silicones and PEGs with ‘naturals’. Self-mutilate and then trying to beat the odds… that kick when you
succeed, if you succeed… I only advice advanced formulators to try that out. So, if you don’t limit yourself to things like ‘from renewable feedstock’ like I do more often than reasonable and get stuck halfway to your dream of perfection, then you should try some silicones and powders (another ingredient family I’m not focussing on but would were I to produce for a living).

[Pharma]

There is not one penetration enhancing ingredient which works for everything nor is there something which would reduce penetration of everything (except wrapping yourself in cling film before applying a product LoL). Regarding cling film and occlusive agents: they’re maybe the best and oldest ‘penetration technology’. They generally increase penetration of most everything if they don’t result in for example a broken emulsion with the actives floating on top.

I’m taking the other example of @Adamnfineman : Mineral oil does reduce menthol penetration by the same ‘penetration mechanism’ it enhances penetration of salicylic acid: Solubility (or insolubility, respectively). If an active ingredient is more soluble in the base than the skin, it reduces penetration (unless the base is readily penetrating skin such as DMSO) but if the active is a lot less soluble in the base than the skin it enhances penetration. A minimum solubility in the base and the skin are more or less required for either effect.

And then there are the other penetration enhancing effects too… many of which are only poorly understood and more theory and guesswork than proven facts. I wouldn’t go as far as saying that penetration enhancers are well known. Some are, true, but most are just abused by marketing and it would only be okay to call them penetration enhancers when the final product in question has actually been shown to do so. Anyway, if you know those effects, then you also know what might be done to revers/weaken them. As a rule of thumbs (guesswork quote > 90% 😉 ) I would say that formulating something (especially emulsions) wherein one doesn’t explicitly plan for enhanced penetration of a given ingredient more likely ends up with a product which hampers its penetration than one which accidentally enhances it.

[Pharma]

@grapefruit22

Thank you! That was exactly the document which I thought I’ve seen but couldn’t find again. I failed to notice then that it’s not a legally binding document but a ‘best practice recommendation’…

I’ll check again what Swiss authorities have to say in this regard. From experience I’d say they will follow the bare bones EU legislation (Swiss VKos is basically that plus a very few exceptions and references to other legal works) which leave ample room for interpretation.

[Pharma]

drjayseesunish said:

@Paprik sounds a very strict teacher is asking ????

Not a strict but a helpful and smart one . This is the one answer (or question) which may lead to any constructive results.

[Pharma]

Recommended literature:

- ‘The Abbott Guide to Rheology’ by Steven Abbott

- ‘Rheology Modifiers Handbook. Practical Use and Application’ by David B. Braun and Meyer R. Rosen

Key message of both: There is not ‘a viscosity’ but diverse types and diverse behaviours you may determin in a given viscous fluid. Haptics isn’t just about viscosity but rheology which is comprised of more than just viscosity (such as tackyness and elasticity).

[Pharma]

It’s simply hyperosmolarity which results in a warming perception on skin by ‘shrinking’ nerve cells.

[Pharma]

PhilGeis said:

@ Pharma -thanks,  think the “preservative -free” marketing hype shows Bayer in this case is unethical.  As you point out, it’s just hexanediol - a synthetic compound that finds common use as a preservative.

Just as an update (better late than never): Astonishingly, my inquiry had Bayer to have a meeting… The tech person called me back and said that their layers are sure that they are in accordance with European cosmetics regulations because 1,2-hexanediol isn’t in the preservative annexe and that they will get away with it being a skin conditioning ingredient, no matter whether or not the product would be contamination free without it. They also think it’s absolutely okay to communicate ‘preservation free’ to retailers and putting this in the brochure (which, they say, is meant for retailers but ‘Why don’t you let some here with the products and feel free to give it to interested customers, just order more if you need more’) as long as it’s not mentioned in TV adds and on the packaging.

I have the impression that they see themselves on the winning side because they just know how to layer up better than anyone who might sue (or rather, they know that nobody is willing to pay money for a lawsuit wherewith no money can be made).

Does anyone here have a more in depths knowledge of EU legal rules in this regard?

[Pharma]

Tocopheryl acetate isn’t an antioxidant, so it might rather be tocopherol (however, tocopherol doesn’t serve any purpose here other than skin benefits because ascorbic acid will protect/recycle it, not the other way round and you might want to add something which protects ascorbic acid). I don’t know if any of the tocopherols dissolve in a 50:50 blend of water and glycerol, I doubt so… Apropos, ascorbic acid isn’t fully soluble in that solvent either. Partial neutralisation might do the job but this will increase its degradation.

Bottom line is: I don’t think it’s okay and that you need to change more than a few things.