Pharma
Forum Replies Created
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Those chemicals are widely used for example as seals or waterproofed (rather everythingproofed) coatings for a plethora of machines, tubings, or vessels which produce, transport or storage stuff such as, well, other chemicals like PEG’s 😉 . In addition to that, they may occur as common contaminant due their very high environmental persistance (they’re part of the family called forever chemicals) and omnipresent use (groundwater, soil etc.).
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If it stings due to pH, it may just do that without any actual damage.
Regarding damage: human skin can deal with acids more easily than with bases. Alkali burns are easier to get than burns with acids (unless you’re useing concentrated sulphuric acid which does half the damage by abstracting water and half by getting super hot when doing so -> you basically char and burn, not etch, your skin *fun fact off*).
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Reminds me of my attempt at extracting frangipani EO back when I was a student. My GF (and now spouse) spent our vacation on Bali and, well, there were all those beautiful frangipani trees in full flower and we loved the smell!
Whatcha gonna do when you’re in vacation and realise that you can’t use dried flowers? Go to the nearest pharmacy (pharmacist turned out to be gay… ‘t was a fun visity) and buy some pure alcohol to make an extract. Lacking any suitable equipment, proper filtration could only be done at home but by then, the brew was brown and had a nasty undertone.
The solution seemed simple: use a rotary evaporator. As quickly done as said, the brew was rotating and evaporating fairly fast. Regardless of the liquid nitrogen trap I installed, all the nice scent molecules ended up in the lab, filling the whole hallway with its lovely scent for 20 minutes, and drawing much appreciative attention by everyone passing by. What I got out of the rotavap was some quite pure alcohol and a concentrated stinky brew but no perfume.
The cuttings we took home lived for 2-3 years before falling pray to spider mites without ever setting flowers… -
That’s not a ‘cosmetic product’ but a pharmaceutical. If pharmaceuticals aren’t your field of expertise, I highly advise against using highly active pharmaceuticals.
BTW good quality hormones are usually used in micronised form (happy inhaling when working with these) due their inherently bad solubility (which comes from their steroid/cholesterol-like core structure). -
Free fatty acids are anionic (in aqueous solutions).
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Hint: Don’t die!
Seriously, the one big issue I see is people not familiar with chemistry trying to deal with one of the most dangerous ‘everyday’ chemicals. -
@Margaret Next time your kids (assuming you have kids) are sick, let them cough into the product (to ensure contamination with the right bug), and sue the company for causing the illness 😉 . You’re not only getting tuition fees for your kids sorted out but also safe other kids from really becoming sick. ????
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GRAS doesn’t mean it’s even allowed in cosmetics… see choline chloride.
Higher % can result in keratolysis. If the aim of your product isn’t of such nature, then you have your onw upper limit 😉 .
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What about water?
Seriously, what exactly is your question and where’s your level of knowlege (not an insult but a basis to build upon)? -
From a purely scientific point of view, mol-% would be used in case of surfactants and solubility. For certain values/characteristics of cosmetics or their ingredients, weight or volume matters instead; so don’t just assume that science = mol ????.
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It contains sodium hydroxide as a base. Add enough and it turns azelaic acid into a water soluble salt. You can check pH 😉 .
BTW all the acids in there would precipitate carbomer, unless they’re all neutralised…
My opinion: Probably not fake but utterly useless because azelates (azelaic acid in salt form) aren’t active. -
There are some theoretical considerations where I don’t know if and when, how, they might contribute to (in-)stability of w/o emulsions.
What we know is the following:
- Fatty alcohols ‘structure’ the water phase by forming lamellar structures. This increases stability and viscosity because these structures are in the outer phase. In case of w/o, they would be in the inner phase.
- Mixed phases are possible but due to the low stability of w/o emulsions and ‘inverse lamellae’ (unlike the other lyotropic phases, lamellar structures can’t be inverted but the oil and water content will be different and hence their performance and effects will differ), coexistance of w/o and lamellar structures are unlikely to work IMHO.
- Fatty alcohols are, as of yet, unpredictable in their effect on w/o emulsions (and also on o/w) because they behave as surfactants and high polarity oils at the same time. The net effect depends on ratios of fatty alcohol to surfactant and fatty alcohol to oil as well as all their absolute amounts and the type of surfactants and oils… If you’re interested in some recent scientific literature on the topic: CLICK
What this publication means is, on one hand. that the effect as emulsifier is not as strongly pushing the emulsion towards w/o but, not very astonishingly, is in the range where the lamellar structure forming emulsifiers are. On the other, the effect as oil is highly favouring w/o (but for that, you’d have to add considerable amounts of fatty alcohol). This still seems promising but then there’s the fact that ‘nobody uses fatty alcohols in w/o because they’re said to kill stability’.
We’ve had that topic last year or so, I think…
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The point you’re missing is biology paired with costs. Plants produce mixtures which can be roughly separated often resulting in medium chain (say C10-14) lengths and a C16 & C18 mixture 😉
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If you had an adic with pKa of 4 and a pH of 4, then, by definition, 50% of the acid is in acid form and 50% deprotonated/neutralised (salt form). Because pKa is a logarythmic scale, at a pH of 3, 90% would be acid and only 10% conjugated acid whilst at a pH of 5, 10% would still be acid and 90% conjugated base.
In your example, you can calculate the values for each acid in the blend separately (the different ratios don’t depend on how much base you added but only on the final pH, which in turn depends on the amount of base).
You can calculate pH from pKa values and amounts of acid and base added (using mol instead of grams) but with blends it’s easier to just measure pH and then calculate for each acid separately.
Unfortunately, the new forum formate doesn’t let me see your original post and I’m currently too lazy to check whether or not I missed something…????
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What else is in that product?
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Alkyl glyceryl esters would be, from a theoretical/technical point of view rather than a practical one, easier to make DIY. However, you’d still need an inert atmosphere (such as equipment to work under a constant nitrogen flow to avoid acrolein formation -> acrolein is highly toxic!) and something for workup (chemical products are typically an ugly mess). Anyway, ester synthesis basically just requires heat (by preference also a catalyst) or enzymes, the new trend in green chemistry. Ethers on the other hand are harder to make (new catalysts have been published recently but can’t be obtained easily). All this isn’t public knowledge but are well kept company sectets. On the other hand, the chemistry behind can be found in scientific papers (which you only understand with a solid basis in chemistry and which most people could only put to good use when having advanced lab skills and/or more intimate knowledge in organic chemistry). HERE‘s a great review article. If you can’t access the paper, then that’s a sign that you’re not in a position where there’s much hope for you to ever be able to do that at home. Me, I could manage to DIY synthesise esters but honestly, ethers are out of my kitchens and budgets capabilities.
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Laptop, Windows 10
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What I don’t like is:
- the formating options… having underline and colours would be nice whilst two types of lists… who needs that?
- lagging: I’ve had now (during these few lines) three laggs but fortunately, the cursor didn’t disappear as it did before in another post
- that I can’t read the above answers. Very annoying to have the forum open on two tabs especially because I still don’t know how to cite (and my answers tend to be longer, so I might forget things and have to look up an above question/answer)
- that I can’t see a button to go back to the subforum I came from before answering except the regular ‘Forum’ botton on top
- EDIT: Search function doesn’t seem to work when searching for more than one word
- What’s ‘blockquote’ and ‘preformatted text’?
- Sorry for only mentioning the ‘bad’ things, I’m better at criticising than giving kudos (if I don’t mention anything, it usually means that I’m happy with it… doesn’t really work according to my wife and my employees 🙂 ).
- How do I upload a file/picture without a link?
- How do I post smileys? EDIT: Okay, it does make smileys… large ones! Let’s try some more 😉 😛 <3 ;( 😀 If only I could get a preview…
- I’m now at a count of more than 10 short laggs…
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Somehow, I can’t reply to the original post but only to subsequent answers???
Aaaanyway… I don’t know why. It’s, as you said yourself, counterintuitive.You’ll find tons of nice graphs on google when searching for ‘sebum composition’ with some examples of artificial sebum which might be copied fairly easily in adjusted form… dunno what else I could contribute. Maybe ‘Try water instead of soap’? LoL!
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True. Although the molecules (usually and hopefully) don’t react, they still interact with each other. Sometimes, there can be quite a difference depending on what you calculate/create. But then again, cosmetic ingredients are often not really pure and the margins of error fairly large…
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Right, I’ve overlooked the 1% line. Full neutralisation of 20% azelaic acid would require over 4% NaOH. That’s really very weird.
Maybe the azelaic acid is micronised? It wouldn’t feel gritty then. Although, the product would also look very wight and probably require a dispersant too. -
True that, you’re right 🙂 .
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..lets discuss
this point if I consider adding more than 2% of fatty alcohol and adding
very little amount of like a tween in a very little percentage besides
high percentages of low HLB emulsifiers of w/o I think we will get
something very similar to w/o cream in performance and more stable as
o/w emulsion but you can consider it a new type as a mixed emulsion, do
you agree with me in this point?Over 2% would be what’s used for lamellar structures. This is likely going to interfere with standard w/o emulsions.
Why a Tween? What good does that do in a w/o emulsion? You mean as ‘hydratation promoter’? Very risky, because this will likely raise HLB too much.
A w/o emulsion is usually never more stable than an o/w one. You can get them stable (in the yar) by gelling the oil phase heavily enough (thinking of traditional cold cream) but this would impart feeling.
I don’t think you’ll get a mixed type emulsion. Feel free to try it out! What you should do then is to prepare the lamellar structure within the water phase (i.e. fatty alcohol plus high HLB emulsifier) and let it settle (which may take up to a few days). Opt for a crystallinisation temp (the melting point of the fatty acid chains) at least 10°C above the temp you use to prepare the w/o emulsion (which, by preference, isn’t of a cold process type). This means that the fatty alcohol of choice is behenyl alcohol. Behenyl alcohol is best mixed with some low HLB co-emulsifier such as glyceryl monostearate, sorbitan behenate, sucrose distearate, or the like to ensure sufficient swelling. To that blend, you’d have to add roughly 10-20% (relative to behenyl alcohol + GMS or similar… best to try the lower % first) of a salt tolerant and non-water soluble high HLB emulsifier (meaning that anionic ones sound great but are usually water soluble, cationic ones don’t play well with w/o, and and PEG-based ones may not work properly due to salt reducing water binding capacity… maybe polyglyceryl-6 distearate or polyglyceryl-10 pentastearate? They also tend to form lamellar structures on their own).
Once you’ve prepared this ‘gelled’ water phase, slowly and under low to medium sheer, add it to an oil phase which contains a fair amount of oil gellant, quickly cool down, and hope that the emulsifiers within the two oil phases don’t diffuse to the other one because else, the system will crash.
Good luck and keep us posted! -
Ahh.. I hope you can revive the old PMs, would be greatly appreciated!
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But mostly a superficial effect which is better on mucosa than regular skin 😉 .