[Doreen]

@Pharma
Thank you so much for your answer!

Totally forgot about the effect on the glass electrode! :flushed:
Glad you brought that up!
Yes I reckoned the IPA was mostly there for solubilizing the Thymol Blue, since it isn’t soluble in water. I know phtaleine dyes have microbial activity, but I think here it is mainly used as pH indicator. The disadvantage is that it leaves stains on the pH meter. :confused:

I have two Extech PH110 Refillable pH Meters, I use one for emulsions and the other for toners, exfoliants etc. (The probes have a flat surface, so they’re very easy to clean, especially when used in emulsions.)
Extech recommends to use the pH 4 fluid (Hydrion Buffer pH-4.00) as storage solution (potassium biphtalate). I use KCl for refilling. Very unlogical, actually. Would the KCl in the probe be contaminated now, you think? So far (since 2016) I haven’t had problems with these meters.

You’re also right about the pH 10. When I started homecrafting, I was like, I want the meter to be accurate in a broad range, because I didn’t know what I would be making, so I chose the regular 3 points calibration at 4, 7 and 10. Actually I only make slightly acidic to acidic stuff, pH 3.5 to 7, so it would be best if I had a pH 2 buffer and use 2, 4 and 7. The most ideal would be the meter that’s used for emulsions on 4 and 7 and the meter for exfoliants/acidic toners on 2 and 4. Point is that I can’t get pH 2 buffers here (for a reasonable price, that is).
Despite all that, the readings are quite accurate and probably accurate enough for my homemade stuff, which I don’t sell.

About preservation. What do you think of phenoxy and parabens, like Phenonip P4? 

[Doreen]

https://www.drugbank.ca/drugs/DB09357

[Doreen]

@Pharma
As far as I know only panthenol (topical), dextro vs levo.

[Doreen]

@ngarayeva001
Sunscreens aren’t for homecrafters to make (including the ones with TiO2 and ZnO), so it’s wise that you don’t make it yourself.
Regarding chemical filters af few ‘bad ones’ have been banned, but for physical, TiO2 and ZnO nano particles are said to destroy coral reefs (and other marine life).
https://www.researchgate.net/publication/261188714_Effects_of_titanium_dioxide_TiO2_nanoparticles_on_Caribbean_reef-building_coral_Montastraea_faveolata

[Doreen]

This could be an option for you:
https://www.makingcosmetics.com/Banana-Extract_p_436.html

[Doreen]

Pharma said:

(…)

@Doreen CLICK and scroll down to page 14 (read the general stuff too, it’s worth the time). As you can see, citrate, malate, and succinate would be useful. Unfortunately, not many standard Good’s buffers are available for the slightly acidic range. MES is basically the only one (not my favourite for lab works or in/on humans) and is widely used in hydroponics (also not my favourite when it comes to plants). In cosmetics, you’ll find for example HEPES (I like that more) in creams which use cell culture media (a marketing ploy); HEPES should be at +/- physiologic pH if done according to good buffering practice.

My recommendation is: buffers are usually not useful in cosmetics. Simply adjusting pH is more often than not sufficient and creates a self-buffering product. If I had a gun to my head and were forced to use one for that slightly acidic range and couldn’t use above mentioned carboxylic acids, I’d go with GLDA (Dissolvine-GL). It’s usually used as chelate but buffers well at that pH range though it’s a bit problematic with electrolyte sensitive formulations if used at buffer concentrations instead of chelate concentrations.

Thanks, Pharma! 
I was thinking about citrate, as citric acid is easy obtainable, plus it’s a polyprotic acid and covers a broad range.

”Simply adjusting pH is more often than not sufficient and creates a self-buffering product.” 
This is my personal observation too. I hardly notice any considerable pH shifts in my own stuff over time .
And since it’s for my own use and doesn’t end up somewhere on a shelf in a store for a while, I don’t need it to be stable for such a long time anyway.

[Doreen]

Pharma said:

lewhitak said:

…if a material is said to be stable using a pH 4.0 lactate buffer BUT after you add all the additional ingredients to the system you are more at a 4.5 or what have you. Do you then have to re-adjust to a pH 4.0? …

You don’t add a lactate buffer but, in that case, just lactic acid and at the end, adjust to pH 4 with diluted sodium hydroxide or whichever base is proposed. Thereby, you create the pH 4 lactate buffer.

@Pharma, what would you personally recommend for a pH between 4.8 - 6? (The ‘pH (skin) neutral’ range)

[Doreen]

Perry said:

If you use a proper preservative there is no reason to heat and hold.  Although, if you are making an emulsion then of course, you would want to heat the system up, hold at high temperature with mixing, then cool. But that doesn’t have anything to do with “purifying” the water.

If someone is heating and holding the water phase to reduce the viable microbial content then they shouldn’t be using that water or raw material source.

Why do you (or people who follow the advice) heat & hold?

Thanks for your personal view, Perry! Much obliged!

I never heat & hold, but this advice is mentioned on the Making Skincare site
https://makingskincare.com/how-to-make-a-lotioncream-part-1-equipment-and-ingredients/

ngarayeva001 said:

Ok, but demineralized water isn’t sterile. (…)

Neither is distilled water, unless it’s the water for injection type that @Pharma mentions, which has had extra treatments (e.g. a filtration step to remove pyrogens etc.)
I do understand however why you heat & hold and buy ‘extra pure’ water. I remember that you wrote a while ago that you had persistant/tenacious fungi problems, even with parabens. That would’ve made me very cautious as well. 
Isn’t there something you might have overlooked during the preparation of those formulas? If you could find that out, it might save you a lot of money regarding energy and expensive water.

ngarayeva001 said:

Well most home crafters can’t send it to be tested for CFU. I read microbial plates sold by repackagers aren’t particularly accurate either. (…)

Where did you get that information, regarding the microbial plates?
I remember a microbiologist somewhere wrote that only plates are not enough, you need an MCT as well, but that doesn’t mean that the plates/slide sticks aren’t accurate. The MCT goes hand in hand with slide tests.
The problem with those slides/plates can be that expiry dates are short, I’ve had several times unused plates that got contaminated during transport and problems with condensation (the reason why the primary packaging around the plates at my work are also sterilized).
I have never used slides or plates from repackers like Lotioncrafter, so I have no experience with those. Maybe it’s worth a try?

[Doreen]

Perry said:

Yes, you pretty much won’t notice a difference if using it in your formulations.

Thank you so much Perry!

If you don’t mind me asking, what is your personal view on heating & holding the water phase?

[Doreen]

em88 said:

(…) What’s the preservative doing there?  (…)

Below what concentration of alcohols, ethyl or IPA (as sole disinfecting agent), would you recommend a preservative in hand sanitizers, by the way?
Aren’t alcohols relatively weak on mold/yeast? If so, I would understand the addition of potassium sorbate.

[Doreen]

Fekher said:

@Doreen thanks for the link, however i’am looking for product where hydrogen peroxide is the active ingredient without using any other active ingredient as alcohol in the proposed formula. 

But I’m still not sure if you’re looking for hand sanitizers or a product for surfaces? Just like @Cafe33 writes, if it’s for surfaces, you’ll find a lot based on hydrogen peroxide alone.
A good working and skin friendly hand sanitizer with hydrogen peroxide as sole disinfecting agent seems unlikely to me.

[Doreen]

What about DryFlo? It’s a selection of modified starches that’ve been irradiated, so from a microbiological point of view it’s better than foodgrade starch.
I added a document about it. It’s available in several DIY shops (Glamour Cosmetics in Italy and Voyageur Soap & Candle for USA/Canada for example).

[Doreen]

MarkBroussard said:

@Doreen:

No, I’ve made teeth whitening gels with 12% H2O2 … the H2O2 contains stabilizers that are quite effective and are designed for the professional market, not the consumer market. 

The common hydrogen peroxide solutions you buy at the pharmacy contain 3% H2O2.

Granted, a solution with 12% H2O2 doesn’t feel particularly good when applied to the skin, it is tolerable.

Ok. With stabilizers you mean carbamide peroxide or something?

Pharma said:

(…)
It’s also a common phenomenon that wrongly applied or overly used bleaching products for teeth lead to a damaged buccal mucosa, canker, and/or inflammatory reactions and can even damage your teeth. Ask your dentist.

I’ve had a homeset for teeth bleaching from my dentist. The dentist makes a special bleaching spoon after he prints the teeth, so the spoon fits perfectly.
But… I grind my teeth. Thought it wouldn’t pose much of a problem, but the gel did leak and quite a bit apparently. And it wasn’t even so much the irritation of the oral mucosa that bothered me, but my poor intestines. I’ve had violent colic pains. Never again for me!

[Doreen]

@Fekher,
This hand sanitizer prototype formula from Clariant only contains a wee bit of hydrogen peroxide (0.52% of 30% H202). 

Besides, isn’t H202 too unstable to be used in dermatics?

[Doreen]

Belassi said:

In my opinion, formulating from scratch is easier than adding things to someone else’s formula and expecting it to be stable. (…)

Totally agree with this!

[Doreen]

I agree with @Belassi.
Years ago I made anhydrous whipped body butters and I tried cooling quickly as opposed to slow cooling and never experienced graininess, nor fat blooms. These were small batches though (about 500 grams).
Make sure that the mixture is completely clear when it’s heated, so that every fatty component is fully melted and then cool quickly and keep stirring. 
I put it in the freezer for a few minutes, stir, few minutes freezer, stir etc. and eventually whipping (when it becomes cloudy).
Whipping can be quite lucrative as the volume increases drastically!

For the pictures below I made a butter with 77,3% shea butter, 10% argan oil, 10% jojoba oil, 2.5% behenyl alcohol, 0.2% tocopherol.

Grainy shea butter

Not clear yet

Without piping

And with.
I know it’s not the greatest result as this was my first attempt piping body butter.
????
And I had chosen the wrong tip: 

Hopefully I could be a bit of help.
Good luck!

[Doreen]

You’re welcome!

[Doreen]

Potassium sorbate gives me flushing symptoms as well. Even at very low concentrations.

Niacin is also known for giving flushing (niacinamide can hydrolyze to niacin under acidic conditions, although it is said this reaction takes a very long time).

[Doreen]

I have no idea how it will work with cetearyl alcohol specifically, or as emulsifier at all. I’ve only used it for neutralizing carbomers.

(source: https://www.cir-safety.org/sites/default/files/Tromet_faa-final.pdf)

This is the answer I got from a professional chemist when I wondered if it was better to use tromethamine as replacement for TEA (regarding i.a. forming of nitrosamines):

“I abandoned TEA many, many years ago in favour of tromethamine for neutralising carbomers and just about all other things that TEA is used for. It never failed me in all that time. I’m not suggesting it is a universal replacement - everything needs checking out, as you know, but I doubt you regret the changeover.

Another advantage of tromethamine is that it has a much reduced tendency to discolour on storage which some deliveries of TEA most certainly do.

The only disadvantage I found with tromethamine in commercial formulating is that of cost but, I’m sure that can be hidden by the superior product that is formed.”

I’m sorry I can’t help you any further on your question about its emulsifying properties. I hope you will get an answer to that as well.
Good luck!

[Doreen]

@ngarayeva001
I think I’ll use Sepimax Zen next time.

[Doreen]

Tromethamine

[Doreen]

@ngarayeva001
I would prefer to thicken the water phase of every HIP emulsion, not only Seppic’s Geltrap. That HIPe I made with PEG-30 dipolyhydroxystearate would be a whole lot better if I had gelled the water phase, I think. Now the skinfeel is very watery, although it leaves the typical W/O water resistant layer.
I made it a few months ago and it’s still stable though.
I’ll experiment some more with that PEG-30 as soon as I have time. Looking forward to it!

[Doreen]

Good luck Belassi! The place looks absolutely beautiful!

[Doreen]

@ngarayeva001
Yes, Zen can in theory go even as low as pH 2. It should also be able to handle the blend Lindsey uses. She just has to try how much Zen gives the thickening she wants.
I’ve succesfully thickened 3% sodium ascorbyl phosphate, which is a strong electrolyte, with only 0,85% Zen in a cream.

[Doreen]

@LuisJavier
You’re welcome! And thanks for the link, I will have a thorough read as soon as I have time.
@ngarayeva001
Interesting. Now I must say that Lotioncrafter doesn’t always provide 100% accurate information, but this indeed is puzzling.