MarkBroussard
Forum Replies Created
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At a glance, the formula looks just fine. Have you done a knock-out experiment making a batch that does not include Tetrahexyldecyl Ascorbate to confirm that this is the ingredient causing the discoloration?
You might also try a combination of Tocopherol, BHT and Sodium Ascorbate to see if you get better stability.
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Here’s the quote from the article, which only addresses total oleic acid:
“Oils with the lowest oleic acid content provide a lower risk of irritant contact dermatitis.”
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Actually, Olive Oil is up to 80% Oleic Acid which is its main component, so I think you missed a decimal point there.
There isn’t a specific ratio that I am aware of that is optimal, but the oils with a high Linoleic/low Oleic acid ratio include Sunflower, Safflower, Grape Seed Oil, Melon Oil, Prickly Pear Oil, Rose Hip Oil. You will also notice that oils with a high Linoleic/low Oleic acid ratio absorb rapidly into the skin, whereas oils high in Oleic acid are “heavy”, absorb slowly and leave a greasy feeling.
Oleic acid is commonly used as a penetration enhancer for pharmaceuticals.
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It is my preferred form of Vitamin C to use in formulations.
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Yes, Phenethyl Alcohol would work well in this type of formula
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I think a trend we’re seeing here is a misunderstanding of what exactly comprises Preservation.
It is not a matter of simply adding a Preservative ingredient to a formula. It’s hurdle technology that includes chelating agents, glycols/diols to reduce water activity and bacteriocides and fungicides that are compatible with the formula.
I use natural preservatives all the time and I rarely fail a PCT because I always use hurdle technology approaches to preservation.
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This is purely a marketing term that is becoming popular in the sunscreen category. The marketers do not consider Triglycerides to be oils … hence “Oil-Free”
Presumably, this is to appeal to people who do not like putting an “oil” on their skin … I can only assume because of the oily feeling and possibly harkening back to earlier decades when people slathered themselves with oil and laid out in the sun for hours on end, baking like potatoes. I presume the reference could also be that “oil-free” sunscreens are healthier for the skin when exposed to the sun for long periods of time and are less damaging to the skin.
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I recently tried it in a formula and found it to be weak on yeast/mold, so I would not recommend it as a stand alone preservative. Couple it up with a fungicide + chelating agent and you should be in good shape.
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The formula is generic … it’s not really a moisturizer and it does not appear to be designed to have any particular effect. So, yes, it kind of does look like a homecrafter’s formula on Etsy. What specifically are you intending this formula to be marketed as … a moisturizer, a body cream?
The good news is that you were able to get two customers to buy it, so don’t fret too much about it. But, you might want to consider adding some functional ingredients unless your intention all along was to make a basic body cream, in which case you’re fine with the formula as is.
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This is also a very good lesson for people who do not have the technical background and/or manufacturing experience who think they can make commercial batches of product on their own.
When a potential client tells me they are intending to “self-manufacture” the products I develop for them as opposed to working through a contract manufacturer, I immediately turn down the business.
All it takes is one or two experiences with this and any chemist can tell you … the amount of the chemists’ time & energy that gets burnt up with incessant questions and frantic phone calls from such a client makes it such that you could never even come out financially break-even on this kind of arrangement, much less make a profit.
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It does not appear that you have any options other than to refund the money. Ultimately, the manufacturer of a product is solely responsible for ensuring their products meet the expectations of the end client and is safe for use by consumers. Since you did the manufacturing yourself, that would be you.
It’s a tough lesson to learn, but you simply have to run PCT on all products that go to manufacturing. I’m sure the supplier of the preservative thought a pH of 5.8 would be fine and told you so in good faith, but they should also have suggested you run a PCT or at a minimum a microbial plate test prior to shipping any product to customers and/or you should have known to take this precaution on your own.
I’ll add to Perry’s list:
(5) Don’t ever put Lecithin in a product unless you have absolutely no choice.
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So, the bottom line is: You adjusted the pH to 5.8, but never ran a PCT on the product that was adjusted to pH 5.8?
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In that case, let me rephrase my advice to you … have a competent professional chemist review everything before you scale up your next batch.
Were your chemist consultants aware that you were scaling-up without running a PCT on the sample at pH 5.8? That’s the only reasonable scenario that makes sense, because all of this is very basic.
That you were going to have preservation problems popped right out upon first reviewing your list of ingredients.
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I see … so you did a PCT with the product at a pH of 3.9, but then raised the pH to 5.8, but did not do another PCT. So, you actually did not pass a PCT at pH 5.8? … that makes more sense.
Gaby, you really should have a professional chemist advise you to make sure that all is in order before you make your next scale-up batch. You are unfortunately learning the hard way from some mistakes on issues that are the most fundamental basics … You must always run a PCT on a sample of the product that you are actually going to manufacture. If you run a PCT, but then make a change to the formula, particularly adjusting the pH up, you need to run another PCT to verify that the revised formula passes PCT.
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I think those changes will go a long way towards solving your problem. Perhaps you should submit samples of your new formula to more than one lab to ensure the PCT results are all positive.
When you submitted your samples to the lab with a pH of 5.8 and Benzoate/Sorbate as the sole preservative, it should have raised some eyebrows.
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The problem with the skin burning is most likely from the Potassium Sorbate causing a flushing reaction. This is common in many people with product containing Potassium Sorbate.
The problem with the preservation is that you are at the very upper limit on the effectiveness of this preservative combination (max 6.0, but really more around 5.0) and with Lecithin and Aloe Vera in your formula you are inadequately preserved against yeast/mold. Also note that you do not have a chelating agent in your formula which would help with preservation. I would have suspected you would have failed the PCT.
No offense, but it appears that the problem is not the preservative per-se, but the choice of preservative and a formula that is inadequately preserved given the ingredients.
I don’t think you have much of a case regarding filing suit against the manufacturer of the preservative.
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I was just teasing with you Jonah. If you are comfortable at 45C and have had other formulations with this emulsifier pass on stability at 45C, then you should be in good shape.
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Well … product stability is a subjective determination after all. Stability at 50C is a much more relevant requirement if you are shipping product in India, for instance, than if you are shipping in the US where air conditioned vehicles and warehouses are much more common.
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This really comes down to a business risk decision. If you really think that the product may be subject to 50C for extended periods of time then you need to make sure it’s stable at 50C, particularly since you now know that it will separate and not reconstitute when subjected to constant 50C for extended periods of time.
LOL, simply lowering your test criteria to 45C may give you a Pass where 50C gives you a Fail, but what does that really get you? A product that still fails at 50C. If you took that approach, then every product could be deemed stable if you simply continue lowering the test criteria at which you deem something to be stable until your product passes.
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Just Google for the chemical structure of the compound you are interested in … virtually all of them are posted on-line. C=C bonds in benzene rings are very stable. It’s the C=C bonds in straight chain hydrocarbon moities that are more reactive to oxygen and the formation of lipid peroxidases.
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An ester can oxidize (or undergo rancidification) if it has as part of its chemical structure an unsaturated hydrocarbon chain. Being an ester in and of itself does not mean it cannot go rancid.
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You could try Olivem 1000 or RitaMulse or Myristyl Myristate with a touch of Stearic Acid yields a nice emulsion
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The answer is “Yes, but” …
Most preservatives are generally broad spectrum agains bacteria, yeast & mold, but many preservatives are primarily bacteriocides or fungicides … strong against bacteria, but weak on yeast/mold or vice-versa.
So, you best look at your selection of preservatives as complimenting each other. Combine a preservative that is strong against bacteria, but weak on yeast/mold with a second preservative that is strong on yeast/mold.
There is little point in combining two preservatives that are both strong on bacteria, but both weak on yeast/mold.
Generally, yeast/mold will be your most likely fail point in preservation, so make sure you add a strong fungicide.
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I think the problem is your Cetearyl Glucoside (and) Cetearyl Alcohol emulsifier. It tends to yield thin, runny emulsions that are not particularly heat stable, so it is not surprising that you are having difficulty at 50C in an accelerated testing scenario.
What happens to the emulsion if you remove it from the oven after several days at 50C and let it sit overnight? … Does it revert back to the same or similar viscosity as your RT samples or does it seem to permanently lose viscosity? … I suspect the latter.
I tried a few formulations with this emulsifier and ended up reformulating all of them with a different emulsifier. FWIW: I no longer use this emulsifier in any formulations.
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No, Shea is pretty much Shea … there are different grades and levels of refinement, but it won’t make that much of a difference one way or the other. Yes, cool it quickly in the fridge for 20 to 30 min, take it out and let it continue to cool at room temp.