fareloz
Forum Replies Created
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Not a chemist by as I understand any organic acid will react with metal ions? I mean coffee machine descales are usually citric or lactic acid. Also Citric acid is usually mentioned as weak chelator.
There is an option of Sodium phytate, not sure if it can be used at low pH, but lotioncrafter says it works under pH < 6: https://lotioncrafter.com/products/sodium-phytate
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Pure ascorbic acid can react with niacinamide under low pH giving yellow Niacinamide Ascorbate: https://skincarewithfriends.com/niacinamide-and-vitamin-c-derivatives-conflict/
But Ascorbyl Glucoside is not pure Ascorbic acid and is formulated at close to neutral pH, so I don’t see any reasons they can’t be combined
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1. It is impossible to answer without knowing your FULL formula
2. 10% polysorbate will give foaming. It is a surfactant after all. Usually used to solubilize a SMALL amount of oil soluble ingredients (extracts). In high amount it gives unpleasant foamy feeling.
3. PEG-40 Hydrogenated Castor Oil is somewhat more aesthetically pleasant
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As an owner of oily skin type I can say ANY occlusion may cause increased number of pimples. So you should not worry about that, usually natural oils and butter are more acne-prone than synthetic inert materials.
When it comes to Dimethicone and Petrolatum I would vote for the latter. Dimethicone leaves a noticeable film and it can peel. Many people with oily skin type don’t like silicone feeling on the skin (personal observation).
In terms of marketing both ingredients are demonized on the Internet, no win if you use one or another.
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You made an acidic product, no wonder it stings at sensitive areas
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Some oils have some volatile silicone mixed in which allows to decrease oil content and improve spreadability of the product. Thinner film - less greasy
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If you can afford to make a second batch of the same weight and then mix them both together you could average the percentage to the required specs.
Basically x = 11.4, y = 37.0, z = 38.0
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The sediment is most likely Salicylic Acid. It is almost insoluble in water.
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Not a chemists, but usually I see next answer pattern on the forum: anionic surfactant, amphoteric surfactant, quats and silicone (dimethicone or amodimethicone).
I guess you are missing silicones in the formula
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In my view exfoliation is always kinda irritation, no?
Glycolic acid will not do much under high pH. What about enzymes (papain, bromelain)? They are usually used for sensitive skin or in summer products.
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Sorry for hijacking the question, but what is the purpose of bi-phase systems? Is it just a marketing story or some formulas really work great as bi-phase products?
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Maybe PEG-40 Hydrogenated Castor Oil?
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So you have adjusted pH of acids, added solution of SA with PG and DMI and got higher pH? How this even possible?
SA is known to be stubborn. 20% of PG is definitely not enough.
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Regular soap?
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Most extracts in skincare are glycerin based. When manufacturer add the extract they have to list glycerin too. Since extract is most likely just a marketing ingredient and added on 0.01% amount to have it on the label, I don’t think there is an issue to mix 0.01% of glycerin with 99.9% oils. If it precipitates you won’t even notice. So your product is basically a mix of 2 first ingredients
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Not as available for DIY as plain Urea, but you could try to search it’s trade name - Hydrovance
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If we make a new batch of the same size and mix it with the original one we will have a double-size batch with averaged percentages. I mean if you take 1g of 10% solution and mix it with 1g 20% solution you will get 2 grams of (10+20)/2 = 15% solution.
The equation is: (original + adjusting) / 2 = target
We know original solution, we know target solution. We can mark adjusting solution as x (y,z, etc) and create an equation. Let’s make one for water (I guess it is the first ingredient):
(64.4 + x) / 2 = 37.9
You need to solve this equation and you will find the numbers:
64.4 + x = 37.9 * 2
x = 37.9 * 2 - 64.4 == target * 2 - original
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Some guy said: “Fake statement requires 5 mins to claim, but debunking requires hours”. Fearmongering is being sold profitably that’s why we have all these “natural”, “organic” etc. It is much easier to use different preservative than fight with all the articles and people on the internet.
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…also it is not as regulated as SA
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It explicitely says except body lotion. You want to make a foot cream. So it falls under (b). The reason body lotions can’t have 2% is because much bigger surface area. Face cream can because face is much smaller -> less product applied and less SA absorbed. Body is much bigger area -> more product applied and more SA absorbed potentially causing poisoning.
Foot cream has small area and it is not body lotion, so it is (B)
Also, you can swap some of SA with Sodium Salicylate
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Does it stay neutralized if the pH is low around 3.5?
pKa is a pH value under which an acid is 50% free and 50% is “neutralized” or better to say is a conjugated base.
pKa of Salicylic Acid is 2.97. So if your solution has pH 2.97 - 50% of added acid is free and 50% is a conjugated base. The higher pH - the less free acid and more conjugated base.
Under pH 3.5 around 23% of added SA is free and 77% is conjugated base (in your case it is Sodium Salicylate).
So “neutralization” is not some point, it is continuous along pH scale. The higher pH - the less free acid and wise versa.
Would that counteract the neutralization from the sodium lactate?
When you mix SA with Sodium Lactate some part of SA replaces Lactic Acid in Sodium Lactate and becomes Sodium Salicylate (+ released Lactic Acid). Sodium Salicylate is highly soluble in water.
Adding more acids will lower pH and release some of SA. But since SA is not soluble in water it will crystalize.
I remember the study you mention, it is here https://www.researchgate.net/publication/44298504_Mixed-solvency_approach_-_Boon_for_solubilization_of_poorly_water-soluble_drugs
Would peg 400 be a better option
I don’t know. I use only PG. You should now worry that much about neutralization. If you can make solution with right pH 3.0-3.5 with Sodium Lactate - that’s fine.
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The reason why Sodium Lactate works is that it “neutralizes” part of Salicylic Acid.
SA + Sodium Lactate -> Sodium Salicylate + Lactic Acid.
Sodium Salicylate is very soluble in water. So you don’t have much of a free acid in your solution.
Same with Sodium Citrate.
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And from here http://www.thecosmeticchemist.com/molecule_of_the_week/guar_hydroxypropyltrimonium_chloride.html:
The dilution and deposition phenomenon occurs when the system is diluted below the critical micelle concentration of the shampoo surfactants, resulting in the formation of the insoluble coacervate
I assume you’ve got insoluble coacervate due to high dilution (too much water?)
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I think Abdullah is right. I just googled the component:
Guar hydroxypropyltrimonium chloride is commonly used as a conditioning agent in shampoo formulations. It forms a coacervate with anionic surfactants from the shampoo formulation upon dilution
So it seems anionic surfactant is causing the problem.