[ketchito]

@Abdullah Don’t get me wrong, LESS is also able to irritate the skin (I used solutions of LESS in the lab to denature some proteins in the past). What you need to do is reduce its charge density, and you do that by mixing it for instance with CAPB. As I mentioned before, the best way to get a mild system is to mix some surfactants that interact with each other (like LESS and CAPB), and at lower doses of each than if you were to use only one or two of them. 

[ketchito]

@Abdullah CAPB and Cocamide DEA have different interfacial propertirs. CAPB interacts more with anionic surfactants through it polar (head) group, forming mixed micelles which increase detergency and foam, and makes the system more mild. Cocamide DEA interacts more through its non polar (tail) group with both LESS and CAPB, making foam more stable/thick and giving more clarity through hydrogen bonding with water. 

That’s why you usually see a combination of the three in very rich-foam products (LESS-CAPB-Cocamide DEA). 

[ketchito]

@Tyss If you want to replace titanium dioxide as whitening agent, you could maybe try some starch (like Tapioca) or modified starch (Akzo Nobel has many modified starches), which will also aid in firmness.  

[ketchito]

mhart123 maybe you can try adding the Propylene glycol into the water phase, and the Methy salicylate and Menthol in the oil phase? Not sure how heating’s gonna affect Methyl salycilate and Menthol’s performance, but that much Propylene glycol added during cooling phase can indeed reduce emulsion’s viscosity.

[ketchito]

@Pharma Thanks again for the discussion and the clarification…I don’t know hoy I missed that sp3 carbon to start with, and the attractive inductive effect of the CO next to the NH2.  

I always appretiate a good chemical analysis 

[ketchito]

This is a guess, but Cocamidopropyl betaine has few contaminants, like DMAPA and aminoamine. Both are suspected sensitizers (especially amidoamine). Decyl glucoside as well is not as mild as coco-glucoside.

What you did in formula b is better in terms of mixing few surfactants in low doses rather than using only one or two.    

[ketchito]

Hi @Pharma, thanks for your comment! I’m curious, almost all nitrogens in the structure of allantoin are in a plane, and their free electrons (which are in p orbitals) can participate in a resonance, so yeah, they are less likely to react…but the pending NH2 has a free pair of electrons in an hybrid sp3 orbital, which even though is not as good as a sp2 to interact, is still a good nucleophile, mostly when the pH is not so low. Wouldn’t it be possible that it could react with carbonyl groups in carboxylic acids? 

Again, thank you for your reply, and for the opportunity to debate a bit

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1501 said:

ketchito said:

Hi Alan. Both Sodium citrate and Bicarbonate are salts of strong bases, which means that in solution, they will form Sodium hydroxide.

So, what might be happening is that your Salicylic acid that is not very water soluble (that’s why the recrystallization), will react with the Sodium hydroxide, forming as a result of neutralization, Sodium salicylate, which is more water soluble.

You could replace both salts (Sodium citrate and bicarbonate) with a bit of Sodium hydroxide.

Hi @ketchito, I have a question. When the Salicylic acid react with Sodium hydroxide and be neutralized, does it still be effective?

Hi! It depends on the final pH of your system. You can use Sodium salicylate at the start, to incorporate it in your system, and then lower the pH a bit, to have part of the molecule as its active form (Salicylic acid). Only, don’t lower the pH too much to prevent solubility issues.

[ketchito]

@alan123 Hi! As @Microformulation mentioned, there are ways to solubilize Salicylic acid. One is to use some solvents (ethanol, glycols and non ionic ethoxylated fatty alcohols). Another is to neutralize it to form Sodium salicylate (either using a base like Sodium hydroxide, or basic salts like Sodium bicarbonate, citrate, phosphate, etc.). Or, you could buy Sodium salicylate instead, which is more soluble in water.

[ketchito]

Hi! That should work, but you need to check the amount of Bicarbonate you’d need.

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Hi! Perhaps your Eucaliptus oil is too heavy, and you need a solubilizer. You could try adding PEG-40 hydrogenated castor oil or Polysorbate 20. 

[ketchito]

You’ll have a solution of Linear alkyl benzene sulfonate.

[ketchito]

Since Allantoin has limited solubility in water (and there are no solubilizers or surfactants in your formula), those crystals might well be from Allantoin.

Another option is that since Allantoin has amine groups (amide to be more precise), they could react with Citric acid or Levulinate-Anisinic acid (from Dermosoft 1388), forming an insoluble salt. Maybe you could try lowering the pH to 4.0 (to reduce activity of amides) or adding a solubilizer?   

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Hi Michelle. Quaternary ammonium compounds are not so good against some microorganisms, and that’s why you need higher amounts than with other preservatives, to reach the MIC (minimum inhibitory concentration).

So, the answer is yes, but you need high amounts of quats. It’s always better to mix it with another antimicrobial. 

[ketchito]

Hi Alan. Both Sodium citrate and Bicarbonate are salts of strong bases, which means that in solution, they will form Sodium hydroxide.

So, what might be happening is that your Salicylic acid that is not very water soluble (that’s why the recrystallization), will react with the Sodium hydroxide, forming as a result of neutralization, Sodium salicylate, which is more water soluble.

You could replace both salts (Sodium citrate and bicarbonate) with a bit of Sodium hydroxide.

[ketchito]

Hi! To have a better insight, I’d advise you to get a couple of books which helped me a lot understand these type of products: “Liquid detergents” and “Handbook of detergents part formulation”. You can download them in many servers like genesis library. 

Those are awesome reads, and they will help you with those questions. 

[ketchito]

Hi! Lauryl glucoside is very effective as a detergent, but it might be too degreasing for a baby wash, especially as a main surfactant. If you want to use a glucoside, use Coco-glucoside instead, and it’d be better if you mix it with a mild anionic, like Sodium cocoyl taurate for instance, of a Disodium lauryl sulfosuccinate which is pretty common in baby products. 

[ketchito]

Hi! I’ve seen that problem in some sticks I made in the past. Butters actually seem to drive this blooming effect. A quick fix is to pre-heat all your butters sepparately before the manufacture. Bring them to 60-65C, and hold that temperature for 15-20 min. Then you can incorporate them into the mix of ingredients (they should be already at the working temperature for your process, to avoid recrystallization).

[ketchito]

Hi! I also believe your oil phase might be a bit high (I think the formula you posted has around 25% +/-), and only VE emulsifier at 1.5% and Sodium stearoyl lactylate 3.0%. Did you check if the product is stable in the oven? 

Also, I believe your Sodium stearoyl lactylate might be the cause of your foaming being an anionic surfactant after all. Can you replace it? You could increase the amount of your VE emulsifier, and introduce GMS or similar to stabilize the emulsion.

If you worry about your costs, check how you truly feel about peptides. Did you perform efficacy tests with and without Matrixyl 3000? did you try with lower doses?  

The pH issue you had with Arginine might be due to the fact that Gluconolactone forms a buffer system in the presence of Arginine. 

For your three tests lowering pH, which acid did you use?

[ketchito]

I agree with the comments above. Sodium cocoyl glutamate gives a very nice sensorial, but it’s very very hard to thicken. I’ve tried with many thickeners, and the only two that worked for me were Crothix Liquid and Versathix. Also, Glycerin in a rinse-off product is a bit of a waste, since being so water soluble, it’d rather wash away than having a real effect on the skin, so you could also reduce it. I’d also add Propylparaben to complement Methylparaben’s activity. 

[ketchito]

Hi Nelson. What you want for making a dish soap is not to make an acid slurry, but to neutralize your Linear alkyl benzene sulfonic acid (LABSA). LABSA is actually a poor detergent, so you need to neutralize it to get the real detergent, Linear alkyl benzene sulfonate. The amounts really depend on how much LABSA you’re gonna use in your formula. If it’s your only (anionic) surfactant, it sould be anywhere between 15-22% (it could also be a little bit less or a little bit more). You can check this Stepan bulletin to know how much Sodium hydroxide you’d need: https://www.stepan.com/content/dam/stepan-dot-com/webdam/website-product-documents/product-bulletins/surfactants/BIOSOFTS118.pdf. Soda ash is a good addition, since it’d help you stabilize the system…0.05-0.1 would do the trick, but then, you’d have to reduce a bit your Sodium hydroxide since the final pH will be very high.

[ketchito]

Hi Nilesh. I had the same issue with a floor cleaner some time ago. The problem with neutralizing Sulfonic acid (LAS) with Sodium hydroxide is that LAS is a weak organic acid and Sodium hydroxide is a strong inorganic base. The result is not a complete neutralization but an equilibrium, and in this system, pH tends to go down. The first sufferers are dyes (which shades depend on pH) and fragrances (if your fragrance is not designed for a more acidic system). What I did is to stop pH shift by adding Sodium carbonate, which serves as an alkalinity reservoir (being able to capture two H+ protons). Sodium citrate could work as well. So, to finally determine this is the same situation, I’d advise you to check if the pH at the beginning and when the system appeared, varied noticeably.