Bobzchemist
Forum Replies Created
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As near as I can tell, you are asking several questions:
1) Can I use Cetiol LC©, Coco Caprylate/Caprate as a substitute for 6 centistoke dimethicone fluid at 2% in my formulations?Answer 1: It’s kind of a weird way to phrase this question, and makes me want to ask “What would be keeping you from making this substitution? Government regulations? A mean grandmother waiting to smack you with a spoon if you do something wrong?” To a large extent, cosmetic chemistry and cosmetic chemists need to embrace the spirit of experimentation, so I have to ask “Why wouldn’t you want to try it and see what happens?”Answer 2: It seems that the question you are really asking is: “What would be the likely result if I used Cetiol LC as a substitute for 6 centistoke dimethicone fluid at 2% in my formulations? This is a more reasonable question to ask. For your butters (assuming they’re anhydrous) you will probably not have a stability problem, but you will loose the silicone skin feel and the long-lasting skin protection that silicone provides. For your lotions, you will loose 100% of the anti-foam and may introduce instability, assuming that the lotions are formulated specifically to support the inclusion of dimethicone.The question of whether Cetiol LC has an advantage because it’s more “natural” is something you will have to decide for yourself. There is absolutely zero scientific evidence to support this.Finally, I have to ask where you are located? At this stage of the global economy, I can’t imagine a place anywhere on the planet that only has access to 3 emollient chemicals - with the possible exception of North Korea. -
What research have you done to find this answer out for yourself?
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I don’t think you’ll get a solution at all - at least, not at oil levels above 0.1%. The best you could hope for is a micro-emulsion, but it’s more likely that you will have to settle for a standard emulsion.
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This is an old article, but still a good reference:
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Have you looked at the supplier formulations available on the web to see what binder systems are being used?
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A frequently useful strategy is to mix a much lower viscosity dimethicone with a higher viscosity dimethicone to improve the spreadability.
Another approach would be to mix the dimethicone with enough of an organo-silicone to allow the compatible use of a light, high-spreading ester in the binder mixture.Finally, you may need to examine how the binder is being introduced into your powder. It is very likely that you are creating the spots you refer to by adding the liquid binder using a method that creates large droplets. The larger the droplets are, the longer the powder mass will need to be mixed to distribute the liquid binder evenly. If your mixing time is fixed, you will need to find a way to create smaller droplets.I am deliberately being somewhat vague, to avoid stepping on toes, but I worked on pressed and loose powder development for Estee Lauder, Maybelline, and Intercos for almost 10 years - If you want to message me to discuss this privately, so that we don’t reveal too much information on the open forum, that’s fine with me. -
@mehran31 - Polysorbates are not alive - they do not gobble up one molecule of preservative and move on to the next. They also do not otherwise inactivate all of the preservatives that could ever be put into your formula. 1 molecule of polysorbate inactivates exactly 1 molecule of preservative, then stops.
So, the industry strategy has usually been to overwhelm the inactivation capacity of the polysorbates with a higher level of preservatives than would ordinarily be used without the presence of polysorbates in the formulation. This higher level must be confirmed sufficient by running a PET/challenge test.Yes, this is an expensive way to do things. Preservatives usually cost much more than polysorbates, so many chemists have tried to find other solubilizers to use that do not inactivate preservatives. -
This is a very big topic - have you done any research yourself on this?
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The easy answer is to just use enough preservatives so that you overwhelm the polysorbates ability to inactivate them.
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Unfortunately, coffee grinders and/or kitchen blenders don’t generate enough shear. Going cheaper than this mixer, but with larger capacity than a muller would require an improvised ball mill. Start with a good quality rock tumbler…like the Lortone 3A or 33B Rock Tumbling Kits
Media: -
If you are not equipped to handle the math involved in calculating this, you should not be trying to make a professional strength anything, let alone a glycolic acid product.
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There are valid reasons for using dimethicone as a binder - what are you trying to achieve by using the dimethicone?
Have you looked at using dry binders?What are you using for a powder mixer and/or powder grinder?Also, what press are you using, and how are you loading the powder into the press?Before I make a binder recommendation, I need some questions answered: Is this a standard foundation powder, or a wet/dry product? Are you using treated or untreated pigments? Lastly, what are you using as a primary powder carrier/excipient (talc, mica, sericite, etc.) -
I just looked at the melanger online - really great idea for lab equipment! If/when anyone uses this for grinding pigment dispersions, please let us all know how it works.
@makingskincare, you should definitely take a look at this for foundations and lip products. -
Thanks, Amanda.
Sorry for getting back to this so late, but I have no idea what media size will work best - check with the mill companies or the companies that sell media. -
@milliachemist is correct. Spots of oil binder on a pressed powder is a classic, textbook example of insufficient mixing before the powder is pressed. The usual solution is to increase the amount of mixing time and/or mixing intensity before pressing the powder.
Dimethicone is not known for being an oil binder that easily spreads out over the powder particles surface, either, (which is what an oil binder must do to work) and, depending on it’s viscosity, may take up to 2 or 3 times more mixing to be properly dispersed than an alternative oil binder would.What viscosity dimethicone fluid are you using? They are not all the same - 350 cst dimethicone is an entirely different material than 20 cst dimethicone is. -
1) You posted “Hi, I need some information on basic testing requirements and testing methods (adopted by cosmetics industry in US) for cosmetics products for their stability, microbiology, and claim substantiating. Also any authenticate online resource on it.” You didn’t ask a question, nor did you ask for our help. You essentially DEMANDED information. I didn’t reply at all because I was so angry - if I had responded, it would have only been to scold you for being so extremely rude and unappreciative. I thought I was being nicer by simply ignoring you - but you haven’t taken the hint.2) As Perry said, none of us answering questions on this forum are getting paid for doing this. We take time out of our busy days to do this because we are trying to build a community. You are not helping in that by raising this issue.3) The information you mentioned is information that most people have to pay for, either by hiring a consultant, or by taking a course, or by putting in the time and effort to do their own research. As far as I can tell, you have done NONE of these things - you haven’t even bothered searching this forum or Perry’s blog to see if any of this information might already be posted. You are basically asking us to give you thousands of dollars worth of very detailed information for free - sorry, not going to happen.
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@milliachemist nailed it. Veegum and CMC are synergistic, and highly recommended for pigmented products. Since you will be getting a reasonable amount of thickening from the gums, you can lower the oil-phase thickeners if you have any in your formula. No other thickeners (Carbomers, etc.) should be needed.
Veegum is made by RT Vanderbilt. They even make a product, Veegum Plus, that has veegum and CMC mixed together.There’s a fair amount of other literature available:Even if I’ve mentioned this before, it bears repeating: Reading supplier literature should be a regular habit for cosmetic chemists and aspiring cosmetic chemists and even hobbyists. Some claims need to be taken with a grain of salt, but there is a great deal of very valuable information in supplier literature that is NOT available anywhere else. -
Can you get hold of any cyclodextrin? You may be able to “encapsulate” fragrance by yourself.
Alternatively, you may not need to encapsulate the fragrance at all - you may just need to have the fragrance adjusted to use more longer lasting base notes and then adhere more of that fragrance a bit more strongly to the fabric. Experiment with different quaternary actives and higher fragrance levels. -
Iron oxide colors won’t drift - but you will need to make sure that your formula has a high enough yield value to support/suspend the pigment particles.
A dye would probably be a better choice - can you get any Red 40? -
“Ponceau 4R (also known as C.I. 16255) is a red azo dye which can be used in a variety of food products, and is usually synthesized from aromatic hydrocarbons from petroleum.Ponceau 4R is considered carcinogenic in some countries, including the US, Norway, and Finland, and it is currently listed as a banned substance by the US Food and Drug Administration (FDA).”@vjay, I have no experience with this material, and I strongly suspect no one else here does either.Most frequently, colors are degraded by the fragrance, so changing or eliminating the fragrance may work.Better yet, run a series of knock-out experiments to determine the culprit(s).
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1) Put red wine vinegar and vegetable oil into a bottle and shake vigorously, then let it sit and observe.
Add an egg yolk and repeat.2) Matching water/oil phase densities typically does nothing for the types of macro-emulsions we make for cosmetics. The micro-emulsions made for food and drinks are a different story. Look up weighting agents, which make flavor oils more dense.more later… -
Judging from your information, you’d need to somehow insulate the bacitracin from the water. From what I know of OTC drugs, the launch is not looking good.
If you’re making an emulsion, it’s at least conceivable that you could suspend/dissolve enough bacitracin in the oil phase to protect it from the water. Proving that this works would probably require a complete re-do of your stability studies, though.If you are making a hydrous ointment without any oil, though, AND all your lab batches are initially stable and have passed long-term stability testing, your only hope is going to be figuring out what is going on in production.The first thing to consider is - Where is the bacitracin going? I’ve noticed that this is a blind spot among many pharma people. Chemicals and active ingredients don’t just vanish - if the assay is low, and the right amount went into the batch - Where is the rest of it? Can you prove it’s being degraded into parts that do not assay as bacitracin? There seems to be a distressing tendency to just accept out-of-spec-low results as failures.If it is being degraded, now you have to figure out what is destroying the bacitracin as processing continues. You’d need to investigate several possibilities. Is it shear? Heat? Contamination? Reaction with the vessel/pump materials? Insufficient batch turnover/mixing leading to concentration gradients? Is the bacitracin separating out for some other reason? If so, where in your processing system is it?