[Pharma]

Using grams is fine as long as everything adds up to 100 g. In this case, grams equals % .

Pregnancy safe? So you’re not going to work with nanonised oxides, are you?

Okay, the old and simple oil-soluble sunscreens (BTW that blend is mostly absorbing UVB). In that case they fully count to the oil phase… anyway, I did some rough maths and ended up with max 1/4 stearic acid which could be neutralised, maybe less. Depends on final pH, product purity etc. That’s not a % which I would deem sufficient for proper emulsion stability, especially not in conjunction with all those w/o emulsifiers.

How neutralised stearic acid affects the system? Well, it turns it into stearate soap or, in other words, an anionic emulsifier. This is something you should know if you’re working in cosmetic product development.

Regarding your Q about a better emulsifier system: That’s like asking ‘What’s a better moon rocket than a firecracker?’ You’re going to have to work with a lot of oxides… good luck with that!

No offence but I sincerely doubt that this job is a job you should do, not with your current know-how. Maybe your managers should switch jobs too…

[Pharma]

Addition to my earlier post: I just realised that there’s AMP in higher amounts present. This indicates that at least some (too lazy to calculate) part of stearic acid is neutralised which makes the emulsion more likely to be o/w. I still don’t think that it will deal well with a switch to ZnO.

[Pharma]

Heike Käser uses mainly nautral, natural identical, or non-petrochemistry derived emulsifiers combined with waxes and fatty alcohols. Many of these show marked thickening over the course of 1-2 days post manufacturing. Depending on the emulsion type, re-homogenisation can actually improve stability and also tends to drop viscosity (the latter is from my personal observations).

[Pharma]

Because I don’t know the 3 sunscreens nor the manufacturing procedure, I can only guess: Judging from the empoyed emulsifiers, this does look like an unstable w/o emulsion or alternatively an unstable polymer-stabilised o/w or w/o/w emulsion. I tend towards a w/o emulsion which only holds because of the high melting range of the oil phase and an inner gelled aqueous phase.

Should you ditch the sunscreens for zinc oxide, remove pelemol
bip-pc and use an entirely different emulsifier and polyme blend (as you noticed yourself, they don’t hold and both will most likely crash when you use zinc oxide) .

[Pharma]

Hexylene glycol is a synonym for 1,2-hexanediol. However, in cosmetics, it often refers to a diol which is not a glycol in sensu stricto: 2-Methyl-2,4-pentanediol.

Hexanediol is a multifunctional mostly used as preservative at lower levels and does not help with eye issues what so ever unless it’s dry skin but its humectancy isn’t that great. ‘Hexylene glycol’ is just one of the fancy glycol humectants and can be replaced by isopentyldiol (if you like it fancy), pentanediol or hexanediol (if you like additional preservation boosting), or glycerol (if you like it cheap). Its solvent capactity might be mimicked best by hexanediol and/or isopentyldiol.

[Pharma]

I don’t like incubators too much regarding emulsion stability. They’re okay regarding chemical stability or if you produce for very hot climatate. However, without knowing your formulations and certain features of it, it’s impossible to say whether or not the 45°C have any meaning.

[Pharma]

Original cold cream relied on wax only which hardened the ’emulsion’… however, this approach has been abondoned by most due to its inherent instability issue.

In Europe, small additions of sodium or potassium soaps or standard emulsifiers are used to increase stability instead of borax which is more common in northern America.

An example formulation made and used in hospitals in Lucerne: Wax 7g, cetyl palmitate 8g, almond oil 60g, water 26g

[Pharma]

It doesn’t necessarily need saponification: Search the forum for ‘cold cream’.

[Pharma]

The new ones used in Europe for example UltraSun. They’re not yet approved in the US if I’m not mistaken.

[Pharma]

It’s a solid powder. Why add a preservative? Maybe you found the wrong one @Abdullah

[Pharma]

Polyol doesn’t equal polyol and some speak of polyol also in the context of glycols/diols.

And then there are different emulsifiers which will react differently.

I’ve read different theories which basically have to do with head group interactions and subsequently changing emulsifier solubilities. However, I haven’t seen any publication which actually calculated or predicted such a phenomenon accurately for example by using COSMO-RS (maybe I just have other interests, maybe I didn’t search good enough, maybe cosmetics doesn’t use COSMO-RS…).

[Pharma]

It’s already on the market for example Magnolia Extract 98 by Cosphaderm which containing mostly magnolol and honokiol. From what I’ve read, it seems strongest against mould. Back in the day I did bioguided fractionation during my semester break also screening different organs from different magnolia species. We found active principles but sadly, never got to the point of determining their structures. Although, we had the suspicion that it was in many cases magnolol and/or honokiol which killd the microbes (one was a multiresistent superbug which we, in hindsight, shouldn’t have handled the way we did… No worries, it didn’t do me any harm *cough-cough* 🙂 ).

[Pharma]

Well… there are just a very few synthetic materials where we haven’t found a microbe which can and will, in one way or another, eat it :smiley: .

To my knowledge, sucrose stearate isn’t especially prone to be ‘bug food’. Ingredients of concern usually provide nutrients which are in limited supply without them. This includes nitrogen, phosphorous, sulphur, minerals and trace elements likely including potassium, as well as vitamins and related growth promoting compounds. Sucrose stearate is sugar and fat, two carbon and oxygen sources already present in ample supply but which on their own would not suffice for growth.

[Pharma]

1%/MW of Zn*MW of zinc PCA

[Pharma]

MarkBroussard said:

…The main problem…they really blow the viscosity of most emulsion…

Ugh… that seems to be a common issue with several alternative preservatives. Thanks for sharing.

Regarding ‘synthetic’ vs.’natural’ phenoxyethanol by Tyger: CAS # for both is the same = both are phenoxyethanol. Dunno why they are allowed to rename the chemical name of one into ‘natural phenoxyethanol’. What do they mean by that? They further claim: ‘The natural version of phenoxyethanol can be used in products in
order to boast the fully natural status of the product as opposed to
containing synthetic chemicals.’ WTF…

They even have a ‘natural’ caprylhydroxamic acid, ‘natural’ ethanesulfonic acid’, and ‘natural’ carbon dioxide. Somebody shoot me, PLEASE!

Usually, synthetic products (100% or at least most of their carbon skeletton) which are made from renewable resources instead of petroleum are termed bio-… like HERE  = may or may not occur in nature. Whereas the term ‘natural’ commonly refers to ‘isolated as is from renewable feedstock’ = obviously does occur in nature. Products which do exist in nature but were synthesised from whatever (petroleum and/or renewable feedstock) are termed ‘natural identical’. I know, this is not an official standard nomenclature but is accepted on a broad basis. Some simply do like to fight over what ‘natural’ means and where it starts or ends. That’s why one should use terms like ‘renewable feedstock’ instead.

[Pharma]

MarkBroussard said:

…
If you look at the chemical structure of Honeysuckle Extracts you will find they are very close to parabens.

Troy also offers a nature-derived Phenoxyethanol if your market will accept Phenoxyethanol.  If that is not acceptable, you might try coupling 1388 with Dehydroacetic Acid…

To my knowledge, there is no specific constituent in honeysuckle which makes it a preservative. It does work according to certain (mostly Japanese) publications though I’m a bit hesitant with all the scams around plant extracts. Honeysuckle contains a plethora of constituents, some like chlorogenic acid and iridoids are active against microbes but are also found in many other plants which do not offer enough bang to be suitable preservatives. AFAIK there is nothing in honeysuckle which remotely resembles parabens unless you regard any phenolic structure as close enough.

Natural-derived phenoxyethanol? Seriously? I can’t find anything from reliable resources. And even if; it’s structure implies that it might exist in nature but only in trace amounts which would make extraction not economic enough to be actually done. My suspicion is that said ‘natural-derived’ version is either synthesised from renewable feedstock using traditional synthetic approaches or isn’t phenoxyethanol at all but just clever marketing.

Dehydroacetic acid has been reported as found in nature long after its initial synthesis. Allegedly, it’s found in Solandra flowers which is quite weird… I suspect contamination followed by referencing to a publication nobody has actually read, let alone double-checked like that story around spinach. Commercial dehydroacetic acid is always synthetic. Sure, its main starting educt can be acetic acid (or mineral oil) flowed by several synthetic steps. IMHO this ingredient does not deserve anything in the direction of natural preservative. All it deserves is ‘biodegradable’. But its INCI is so nice, blablaACETIC ACID, that sounds like apple cider vinegar. How can’t you not love such an ingredient? Maybe marketing should invent better, less conspicuous names for preservatives or do a re-branding like with rapeseed oil (what a horrible name!) to canola oil.

[Pharma]

PhilGeis said:

Pharma - think useless as its too prone to pH (>7) and microbial esterases and it’s a common “preservative” in so many of the recalls in US.  And it’s not that hot when it’s stable.

GMCY or undecylenates? You’re likely referring to GMCY… I always wondered why such a simple small ester shouldn’t be digested right away. Regarding stability at pH>7: one shouldn’t use such a pH when combining with anisic and levulinic acid. At least that concern is no issue.

I never studied the LOI of recalls, good you mention it.

Not long ago I stumbled upon caprylyl glyceryl ether (Velsan CGE). At least, that one is a more stable ether. Any insights to share about this one?

[Pharma]

helenhelen said:

@Pharma @Graillotion How does macadamia oil feel compared to avocado oil?
…
@Pharma On the topic of esters not being used for moisturisation, what do you think of dicaprylyl carbonate? It’s one of the few vegetable oil alternatives that I can add without making a cream drying on my skin, and I like the cushioned afterfeel. I notice BASF describe it as a “carbonate” rather than an “ester”. Is there any reason why dicaprylyl carbonate would be less drying on my skin (when replacing a vegetable oil) than most other esters?

Avocado oil on my skin feels oily and sticky, mac nut oil is just wonderful, smooth, and sinks in beautifully without that drag most others have. Hard to describe…

I have dicaprylyl carbonate and it does feel pretty much like all the other low viscosity ester oils. It is a ‘double ester’ wherein the acid part is carbonic acid instead of a fatty acid. I have no idea why it does what it does on your skin. However, its structure is somewhat different and its interactions with skin are expected to be different too. Still, I’m somewhat astonished and will do a trial, neat, carbonate against ester oils, next time I take the bottle into my hands (if I don’t forget to). I should also ask my wife to participate, her skin sounds like yours… I often joke that she could survive simply by using body lotion instead of eating.

[Pharma]

@domicanica That’s why I combin it with pentanediol (1,2-hexanediol would be even better). If users get unwanted reactions to preservatives which are used at the higher end of their active range, you might consider lowering it and adding a lower amount of another preservative to balance the difference. Sure, you’d get a longer LOI with more preservatives people might take offence at… there are several pros and cons regarding more complex preservative systems.

@PhilGeis What are your thoughts about undecylenic acid as well as salts and derivatives thereof against moulds?

Regarding your comment on GMCY: Fairly useless as primary preservative or as booster/add-on too? I certainly wouldn’t use it as primary (acutally, none of the several capric and caprylic derivatives) but as part of a hurdle approach.

[Pharma]

I use it for personal projects but combined with GMCY, pentanediol (and/or other glycols), and certain plant extracts and/or isolated plant constituents (such in which I trust to be what they claim to be, not weird fermented stuff or the scum by Active Micro Technologies).

Do I know for sure that this blend works: NO, I don’t. Were I to sell it, I would have it tested (mostly because I’m not sure how well it protects from mould).

[Pharma]

helenhelen said:

…She definitely avoids almond oil in cosmetics, but has said she would only “probably” avoid macadamia oil.
…
I have tried ethyl macadamiate. It doesn’t offer my skin any moisturisation as such, I would only ever use it for the feel as it’s very light and fast spreading. But I didn’t feel it offered any benefit over other fast spreading esters. I can’t remember exactly but I think it also absorbed too quickly for me. I am usually trying to extend playtime rather than speed up absorption!
…

Go with highly refined oils and butters and there are as good as no allergens left (because these are proteins). Sure, highly allergic people shouldn’t eat them but for the rest of us…
Correct, the combo macadamia and ethyl ester results in exactly what you describe. For me, this is very interesting but for dry skin not so much where native oils and butters are a better option than ester oils.

[Pharma]

Food grade sucrose stearate often consists of a higher % of sucrose distearate (which has an approximate HLB of 6) or broader blends of different molecules whereas cosmetic grades come for example as ‘HLB 11’ or ‘HLB 15’. Meaning, these cosmetic grades are either 1:1 sucrose monostearate to distearate or 70% monostearate, respectively (however, anything from 10 to >80% monostearate is available). As a consequence, you can’t exchange food grade with cosmetic grades just like that.

Here some reading: CLICK, CLACK, and CLOCK.

[Pharma]

Ethyl macadamiate should have the same proportions of fatty acids as the native oil.

However, ethyl macadamiate is neither macadamia nut oil nor oleic and palmitoleic acid .

Also couldn’t find it a repackers, would love to try it! All I need is a vacuum pump and a tap water adaper so I can finally make my own (I have the rotary evaporator, a reflux system, and all the required chemicals…).

Can I buy a useful but cheap vacuum pump (China style LoL) on Amazon?

[Pharma]

Which form of arginine did you use? If free base… I guess the high pH did lead to degradation (of either or both) and partial deprotonation of the ammonium part of taurine. Taurine is fairly stable and remains zwitterionic under more ‘normal’ conditions. Also, arginine salts are quite stable in water. Dunno how stable arginine free base is, though.

[Pharma]

BTW I’m honestly not entirely sure but I think Shea nuts are also a true nuts as well as different seeds from which other cosmetic butters are extracted…

And @helenhelen once you used mac nut oil (phytosteryl macadamiate is not the same!) you’ll stick with it for life 😉 . I’ve tried avocado oil, it’s miles away from mac nut oil, not close to the same league!

The only oil I like more than macadamia oil is pistachio oil, but for eating, not in cosmetics 🙂 .