[Pharma]

We had that discussion before here on board, use the search function .

Who sais dog skin has a neutral pH and that this is also a healthy pH?

[Pharma]

Depends on the emulsifier used.

Probably around 5-ish?

[Pharma]

True, the higher the temps, the higher vapour pressure. With potentially flammable material, their flash point shouldn’t be reached. Vapour pressure is a factor where time is of the essence (hopefully, it doesn’t boild down to how long you can hold your breath LoL) if you don’t have hermetically sealed mixers and if you do, they should be made to withstand the theoretical pressure of the used volatile ingredients.

Regarding D5: It’s a common solvent for silicone polymers/elastomers and emulsifiers. Some of these are hot process only . The advantage of D5 over non-silicone volatile compounds is that it has low toxicity/irritation potential, no odour, high termal and chemical stability, and it’s difficult to set on fire (although, it is possible to ignite in vapour phase).

BTW use THESE settings in Google translate :smiley: .

[Pharma]

@JLLL18 I might be able to help you out… regarding the ‘touching and being romantic part’ :blush:

Sorry, joke aside: It would be really interesting if you could keep us posted about your progress.

OT @biofm I finally got two of your ILs (through a friend… less hassel with the paperwork… *cough-cough*). Really excited and looking forward to play with them. However, I was a bit astonished how strong they still smell of DMEA.

[Pharma]

Oui, c’est éthoxylé

[Pharma]

The interaction found in that publication is with Optiphen, not with GMS . And FTIR alone is no proof, just an indication.

It’s a poorly made publication, too.

[Pharma]

BTW is you freeze powders and other solids: Thaw them thoroughly (an hour or two) prior to opening the container or moisture gets in. It may pay off to put a smaller amount into a separate jar or two (faster thawing and less freeze-thaw cycles).

[Pharma]

Without link: http://www.stevenabbott.co.uk

It’s probably also because w/si emulsifiers were designed for cosmetic w/si emulsions whilst w/o emulsifiers tend (at least the older ones) to come from other fields of use, such as the food industry. Long shelf life hasn’t the same meaning in food than it does in cosmetics.

Take for example PGPR: You’ve likely came across this one. Great for processed food but in cosmetics *yikes!*… It has one virtue none of the other cosmetic emulsifiers I’ve seen so far has: It has super long lipophilic tails. This makes it very ‘slow’ (takes time to diffuse to the emulsifier interlayer) but it binds diverse types of oil to the interface, thereby creating a ‘sturdier’ shell around the water droplets. The feel however… I really don’t like it. Also, shelf life is in the range of months, from what I’ve seen so far, and it tends to result in multiple emulsions (o/w/o).

The trick might be to use it at (guessing here) 20% of the amount of your primary emulsifier to notch up your product. However, with PGPR it’s mandatory to combine it with a small, low HLB emulsifier such as a monoglyceride, sorbitan ester, or a di- or triglyceryl mono-, sesqui-, or diester.

The tendency to create multiple emulsions also makes the process (of making the emulsion) more prone to errors and deviations.

[Pharma]

Disposable ice cube plastic bags? :smiley:

Or use more eco-friendly silicone moulds, also available for mini-cubes… all you have to do there is refilling them into a jar once frozen.

[Pharma]

HERE is where you can read about the supposed mechanism for this behaviour. It’s not an evident 1+1=2 thing… there seems to be an interaction (or lack thereof) of the oil molecules with the alkyl chain of the emulsifiers (or in the other phase, glycols/polyols with the hydrophilic heads) which push them apart (or let them interact with themselves, respectively). This leads to a shift in appartent HLD/HLB values or, in other words, a different curvature of the interface layer formed by emulsifiers.

Take for example 10 pencils (or a few less) and bind them together with a string forming a ladder (with just one string in the middle) with a spacing of maybe 1-2 cm. The string is the interface whilst the back sides of the pencils represent the oil phase and the cap sides the water phase. If you, as an example, increase the diameter of the caps, the ladder bends to give a o/w droplet. That’s the part you’re certainly familiar with. Now, if you squeeze something between the pencils, the same bending takes place. In a w/o emulsion, we want nothing between the heads in the water but lots of material between the oily tails. What better to use than an oil which has some affinity for the more hydrophilic part and will love to stick close to the interface/string? That’s also the point where fatty alcohols start to create confusion… they should work even better than ester oils but they don’t…

Hope you understand my explanations 😉 .

[Pharma]

Why not freeze the excess until you need it?

[Pharma]

ngarayeva001 said:

…
2) The second is the stability of my foundations (and W/Si, W/O in general). Here are a couple of tricks that I learned:
- use several emulsifiers
- oil phase stabiliser is not optional, it’s a must
- repeating common knowledge, the electrolyte in the water phase is a must
- the type of oil matters
…

Small addition to those four points:

- By preference, one of which should be polymeric (better long-term stability) and one a small monomeric (‘faster’, helps with initial emulsification).

- With probably one exception wherein too much oil gellants make the product feel weird, almost brittle: HIPE emulsions.

- I wouldn’t say electrolytes are a must, but they have, off the top of my head, three different modes of action which all help in diverse ways. Working without them is probably not worth time and effort because, I suspect, there are no suitable and esthetically appealing emulsifiers available. Again, HIPE emulsions are a class of their own and may work without (or at least, without any extra addition besides the active ingredients which may already be electrolytes).

- Theory has it that high polarity oils (ester oils) are better suited than nonpolar oils such as hydrocarbons (squalane probably being the worst). The right choice of oils also helps, according to the HLD system, to reduce the amount of electrolytes needed.

And three more in addition:

- For some weird and, to me, unexplainable reason, fatty alcohols don’t do any good in w/o emulsions.

- Again from the HLD system (haven’t tried it properly myself to be able to confirm this theory): Longer chain glycols (>C6) are allegedly better suited than short chain ones (C2-C5), glycerol and polyols.

- Do not use ionic emulsifiers for several reasons, not even at levels as low as 1/20 of the amount of total emulsifiers added. Seems obvious because they have a high HLB but they sometimes come disguised as part of active ingredients. Smaller additions of nonpolar ones such as Tween-20, another functional additive in active ingredients, also has a high HLB but may be tolerated to a degree.

[Pharma]

Get some which doesn’t smell/reek .

[Pharma]

Maybe spoiled, maybe cheap quality

[Pharma]

Oral isotretinoin is highly likely to cause severe mental and/or physical damage to the kid if taken during and even several months prior to pregnancy. Also, it’s not advised to take it as man if you’re planning on ‘making’ a baby.

Viagra can cause blood pressure issues or mask prostate hyperplasia (which may ultimately lead to prostate cancer which is potentially lethal if untreated).

Bottom line is, it’s seldom a good idea to take prescription drugs without consulting a doctor.

[Pharma]

And

Dibutyl Ethylhexanoyl Glutamide. Ajinomoto sells them, I think also as a combo.

[Pharma]

It usually depends on many factors, not just side effects, such as indication (a drug for a serious illness which requires a doctor and not the patient to make the diagnosis is likely to be a presctiption drug), duration of therapy, therapeutic index/safety, potential for abuse/addiction/precursor chemical and so on…

At least in theory, a drug which isn’t effective doesn’t get approval as a drug.

And then there’s also lots of lobbying and other non-scientific factors such as personal opinions/interpretations of the people working at the responsible agencies which results in the, sometimes marked, differences even between countries with similar regulatory frameworks (not approved in one, prescription in another, and OTC in a third).

[Pharma]

@drjayseesunish You might want to answer the questions @Abdullah posed, they’re mandatory to give further advice.

[Pharma]

PEG-based surfactants/detergents are temperature sensitive. The solution would be to either not let your product get cold or change the detergent.

You can also play with additives such as alcohol and change the amount of salt (if you have any).

Maybe check out some manufacturer’s brochures or the like.

[Pharma]

moomin said:

Thanks for all your ‘supporting’ advice! NOT! 
Here is where I am at, I wanted to find a natural deodorant, I found a recipe that included milk of magnesia and essential oils, it worked wonderfully for me (no burns! fancy that!) and so I thought I might make something similar as a sellable product, not using milk of mag but using the stuff in it. I’m not a chemist, don’t have a clue about chemicals, hence why I’m on here, but I just didn’t realise that I would be meeting with a group of guffawing henrys, who think it’s hilarious and ridiculous that someone doesn’t understand about chemistry! well sorry I got it wrong, I misunderstood this site for support and help!

So, telling people to not do something in order to avoid getting injured isn’t supporting advice? What then? I’m not laughing either… I’m telling you loud and clear: Don’t do it!

Or are you expecting something like: Simply add apple cider vinegar to get the stuff dissolved? Well, sure, do that, it will work (it also makes your concoction less dangerous).

If you would have read my reply without switching of your wits the instant you saw a chemical formula, then you would have seen that I’ve told you that magnesium hydroxide (milk of magnesia is a trademark by Bayer) may work without causing too much harm because of very poor solubility. And that also explains why you will always have a precipitate (you can’t dissolve a rock in water unless you change it chemically… and then it’s no longer considered a rock).

BTW the older magnesium hydroxide gets, the more it turns into magnesium carbonate. Maybe you’ve got mostly that.

Why on earth do people touch and even mix chemicals without some basic knowledge of chemistry and the stuff they’re handling? You’re not eating berries and mushrooms you find in the forests but which you don’t know, right?

How comes you think about selling a cosmetic product when you don’t know the basics of cosmetics and human skin physiology? What you’re planning on doing is lacking any due diligence, is highly negligent, and potentially dangerous. A splash of your brew into the eyes can damage them permanently within seconds.

You’ve probably never heard of ‘pH’. That’s something very useful… it doesn’t just tell you how dangerous something may be but also how badly it will damage your skin barrier (the acid mantle and sebaceous layer) and your skin microbiom.

[Pharma]

TimMcG said:

…Can someone point me to a good resource to calculate the requirements?

If you happen to have a Windwos computer, go to the search bar (the magnifying glass usually on the lower left), type ‘calc’ and hit Enter .

[Pharma]

Magnesium hydroxide mixed with sodium bicarbonate for a skin leaf-on product?

Let’s see what chemistry has to say:

Mg(OH)2 + 2 NaHCO3 -> MgCO3 + Na2CO3 + 2 H2O

Re-calculating from g to mol-fractions to adjust to your 2 + 2 g:

1.44 Mg(OH)2 + NaHCO3 -> 1/2 MgCO3 + 1/2 Na2CO3 + H2O + 0.94 Mg(OH)2

= ~1/3 of the poorly water soluble magnesium hydroxide (poor solubility is the reason why people don’t get chemical burns that easily from it) turns your ‘mild’ bicarbonate into caustic soda. Caustic soda can be used to make soap… if that’s what you want your skin to turn into, go ahead! It certainly saponifies the bacteria and stink molecules as well.

You’ll certainly find some idiotic advice online on how to get rid of scars from chemical burns (probably where you’ve found that deo seppuku concoction).

[Pharma]

What are you trying to create?

This doesn’t seem a healthy mixture… or rather suspension, because the magnesium salt isn’t water soluble (essential oils aren’t either, though they don’t crystalise out).

[Pharma]

ketchito said:

…
So, if I’m not mistaken, everytime there is a test required from orgamisms like REACH and ECHA as long it is not for cosmetic purposes, it’s possible to test in animals and still comply with “cruelty free”, right?
…
2) PEG-4 rapeseedamide, for which Kao said they conducted a Repeated Dose 90-Day Oral Toxicity (OECD 408) in 2014 but not for cosmetic purposes, which I believe was done for REACH registration, but I’m not quite sure.
…

Correct.

Oral toxicity can be for REACH/ECHA as well as for cosmetics (remember, many cosmetic ingredients weren’t invented by cosmetic companies and are therefore mainly used for other purposes than cosmetics)… however, both would be for reasons regarding consumer safety and hence be ‘cruelty free’.

A ‘cruel’ product is/was usually a cosmetic product (pure chemical but mostly a mixture/final product) which is/was tested on animals (and most often could as well be tested on humans or in vitro) to ‘proof that it works as a cosmetic product’ (= cosmetics usually don’t work beyond what can easily be determined using human volunteers; drugs work and, unfortunately, require some animal testing).

PS. Sorry for the many parentheses… my answer is really not easy to read.

[Pharma]

% concentration is usually referring to weight-% (unless it’s ethanol, then it might as well be volume-%). Hence, it doesn’t matter which molecular weight your product has. If you were to make an X molar solution, then it would… but you’re not, are you?

Anyway, a 50% solution usually means (most likely also in your case) that the final solution contains 50 weight-% of a solid: 200 g solution contains 100 g solvent and 100 g solute. Mind, the resulting volume may not be what you’d expect it to be (namely 200 ml)! Depending on what you dissolve, there can be more or less no increase in volume (often with inorganic salts where some even cause a minute shrinkage of the volume) or an increase more or less corresponding to the density of the solute (mostly nonionic solutes). Here, many mixtures don’t have a linear concentration-density (or volume) correlation (ethanol as a prominent example).