Bill_Toge
Forum Replies Created
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there are not many threads I’m astounded by, but this is definitely one of them
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@MarkBroussard are there any other materials which have such a wide variation in required HLB?
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required HLBs fall into two distinct ranges: W/O is around 3-6 and O/W is around 8-15, so it’s easy to tell which one is which
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my favourite misnomers are ‘gingsing’, ‘methly paraben’, ‘proply paraben’ and ‘Cosmic Red’ (as opposed to Cosmetic Red), which all came from one former QC lab technician; he was intelligent and good at his job, but his spelling was atrocious
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try using emollient esters rather than mineral oil
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5 is for W/O, 11 is for O/W
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apparently there’s no emulsifier either (emulsifying wax won’t do the job on its own); I strongly suspect that besides being incorrectly declared, the INCI list is also incomplete
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@zwapp has any research been done on the effect of radical chain terminators, e.g. BHT or benzophenone derivatives?
(since photoisomerisation occurs via a radical mechanism, chain terminators could in principle halt the reaction before it starts)
also, I’m surprised that photoisomerisation favours the cis form; unless they’re macrocyclic or physically constrained in some other way (which resveratrol isn’t) the trans form is usually favoured where stilbene-type molecules are concerned
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I’d suggest using one of the Gantrez series from Ashland, or the Luviset series from BASF; your distributor should be able to advise which one is best suited to your product
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in this context it shouldn’t make much difference either way; NF and BP are different pharmaceutical standards (NF is American, BP is British), and both materials will do the same job
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the ingredients list is on the last page of the product information sheet (which is in German)
“Dünnflüssiges Paraffin” is more typically translated as “light liquid paraffin”, and it’s an emollient; the same is true of “Dünnflüssiges Wachs” (C10-C16 ethylhexanoate)I would guess peracetic acid is a disinfectant; although I can’t seem to find any monograph for it, I’m guessing there is one somewhere in the DAB or Ph.Eur, as this appears to be a legitimately authorised pharmaceutical product
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my view is that “preservative free” is much more open to legal challenges
if the formula has a high enough water activity and an appropriate pH to sustain growth but doesn’t actually do so in practise, the only logical conclusion is that a material, or combination of materials within it is acting as a microbistat or a microbicide
and it would not be unreasonable for microbistatic / microbicidal materials like this to be regarded as preservatives in a court of law, whether or not they are intentionally added for this purpose, and whether or not they’re listed on Annex V
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personally, I’ve always taken the view that the term ‘self-preserving’ is more factually accurate, and less likely to land you in legal hot water than ‘preservative free’
also, I understand glyceryl laurate is equally effective as an antimicrobial, and less likely to make your product foam than lauric acid (that said, I’ve never used it personally, so take this with a pinch of salt)
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it also depends on what kind of emulsifiers you’re using, the desired rheology and viscosity of the finished product, and how the product’s viscosity varies with temperature - in short, there is no simple one-size-fits-all solution!
from my experience, making the appropriate choice of emulsifier is more important than the level; the emulsifier(s) need to be chemically compatible with both the water and oil phase, and have the correct HLB for the oil phase
if emulsions show inherent instability that’s independent of temperature, it’s usually because the emulsifying system has failed to meet one or both of these criteria
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I have used Miracare SLB in my last job, and my view is that it’s just a blend of common surfactants sold with some jargon to justify a relatively high price tag
Miracare SLB used to be the kiss of death for any NPD project in my last job - it grossly inflated the cost of product and made it way too expensive to sell to any customers
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what’s your formula, what’s the pH, and what preservative(s) are you currently using?
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which dyes are you using, exactly?
also, is the water in the product chlorinated? (excessive chlorination can cause rapid colour fade)
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the fundamental reason nail polish is such a huge fire risk, and why very few manufacturers make it from scratch, is because it involves handling cellulose nitrate, which, although it’s well-behaved in solution, is EXTREMELY flammable and prone to ignition when dry; and once it’s alight, it’s very difficult to put out
compared to cellulose nitrate, the solvents are relatively easy to handle, provided that proper care is taken
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@David living bacteria in cosmetic products are not actually forbidden, but there is a well-defined COLIPA standard for microbial quality, and enforcement agencies over here crack down on bacteria- or fungus-blighted products a lot harder than they do in the USA
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that’s a very open-ended question: what I would change depends on what particular physical aspect of the product is deficient, or that the customer wants to change
that said, personally I’d get rid of the Sepigel in the second one and put in a better emulsifying system
and diazolidinyl urea is permitted in the EU, up to 0.5% - see Annex V/46
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@eisen cosmetic preservatives are not chemically sophisticated enough to tell the difference between ‘good’ and ‘bad’ bacteria; anything which is effective against Gram positive bacteria will prevent the growth of (or directly kill) Lactobacilli
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the other big question is that even if you do create a product which is microbiologically live for a substantial period of time, how would you convince European national authorities that your product is safe if they test it, find it full of live bacteria, and order a recall?
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although they have Lactobacillus listed among their ingredients, it is only ever sold as dry, i.e. dead cultures (as far as I know), and it is not possible to sustain a live population of bacteria in a cosmetic product without severely compromising its safety
even if they did have cultures which were live at the point of manufacture, there are a number of preservatives listed in their formulas, so these cultures would not survive for long
in short, they are either lying or severely mistaken
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the former is a skin peeling cream containing TCA (which presumably stands for trichloroacetic acid), making it an unlicensed medicine
what makes it particularly egregious is that it’s sold in Europe, where TCA has been banned from cosmetics since 1979!
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product-specific legal limits for preservatives are determined based on the product type, how it’s used, how much of it is used, and the parts of the body on which it’s used; the physical form of the product (whether it’s liquid or solid) is irrelevant
also, what’s an anhydrous safety certificate assessment?