Pharma
Forum Replies Created
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Why 8% IPA?Benzalkolium leaves a slippery film on surfaces. Personally, I don’t like that: using it to clean the shower and don’t tell your wife -> someone is going to die today
.BTW is your product meant to be used pure or diluted? -
nabilram said:…Can some one see what missing?…A second emulsifier.I suppose 1,5% ceteareth-12 is not enough even if you have cetyl alcohol in your formulation (BTW 6% is a lot and hence tends to act like a wax/oil rather than a “co-emulsifier”).
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Phenethyl alcohol is particularly weak against gram-positive bacteria but being somewhat volatile makes it a good headspace preservative (better than phenoxyethanol). Advantage/drawback might be its rose scent. It can be irritating for the eyes and might taste unpleasant but I have no personal experience in that regard (besides, many cosmetic ingredients do that in concentrated form).It’s recommended to be use in blends for example with wetting agents like glyceryl caprylate or caprylyl glycol (or such that @MarkBroussard already mentioned).
If/when I have to restock preservatives I am considering to give it a try.
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Coconut water is as fragile as aloe juice and there’s no difference to aloe powder.Still, I suspect it’s a matter of physical stability rather than microbial spoilage.
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MarkBroussard said:…
I may be wrong, but I don’t think there is a huge market clamoring for “Preservative Free” toothpaste. I find it ironic that people who knowingly consume preservatives in their food products would have a problem with food-grade preservatives in their toothpaste.
…I don’t think that, except maybe for eco-labels, any of all the toothpastes we sell (and which are without added preservatives) claim that they are actually preservative free, it’s the same marketing on them as always “New formulation, bright white teeth, no caries…”. If brands such as Colgate, Meridol, Elmex, Sensodyne, Odol etc. don’t use it, it means that that trend has not (yet) arrived in the toothpaste sector.
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Not just there, you won’t believe how many manicurists and podiatrists we have who think that adding some salt or a few ml vinegar to the washing solution suffices to sterilise their equipment. It goes without saying that they are valuable contributors to our business by creating new wonderfully sick customers :smiley: . Well, it’s disgusting to see those feet… but what don’t you do for $$$?And the other guy who sells home-made sun and love imbued aqueous flower potions in his esoteric store… preserved with some drops of schnapps.Honestly, it’s very astonishing that we don’t have more deadly sick or even dead people. Human stupidity is really scary! Ever heard the proverb “You don’t mind if you’re dead, it’s only hurtful for the others… it’s they same if you’re stupid.”
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Why do you double-post?
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Does it also discolour when omitting citric acid?I suppose it’s either aloe vera juice which spoils (an antioxidant might help) or the emulsion is not stable (formation of larger droplets -> decrease oil content and/or add a co-surfactant and/or increase xanthan). You could also try to replace aloe vera with plain water and see if the same thing happens.How much oils and detergent does your shampoo contain?
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@Perry Self-preservation is also preservation, it just sounds nicer to print a “Contains no preservatives” on a package because consumers love that phrase.Most of the toothpastes here around don’t contain extra preservatives because toothpastes usually have a very low water activity (a high amount of polyols in most cases, sometimes also PEGs). As stated by @Herbnerd, many toothpastes are also alkaline.
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Another strategy, apart from glycols and other humectants, is gelling water phase (think gummy bears which are actually gelled glycerol/sugar rich water and they rarely “sweat”). A different option is using insulated lids such as those with “styrofoam” or plasticised “cardboard” inserts, thick ones which contain air in between, jars with a second smaller “cream cover”, airless dispensers, or tubes. Although, tubes will still form condensation and extra care has to be taken in order to preserve head space since condensation drops are the first place where microbes grow.
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I thought so too. But hypothetically, I can imagine that in a 30% propylene glycol solution apparent HLBs should be different (higher) and glyceryl oleate perform “better” since it has a higher solubility in the not so aqueous water phase…As a side note: Sucrose stearate has not one HLB since sucrose stearate is not a single molecular entity in a chemical sense but, especially if used as food additive, a mixture of either mono- to heptastearates (see also food additive E 473) or mono- and diester mixed with residual glyceryl mono-, di-, and tristearate (usually referred to as sucroglycerides aka E 474). Hence, “sucrose stearate” can cover every HLB from 1 to 16 (HLB 16 is hypothetical and would be pure monoester, HLB 15 is the commercial highest grade with >70% sucrose monostearate, HLB 11 is ~50-60% monoester and ~30% diester, HLB 6 is each ~30-40% mono- and diesters, HLB 3 is roughly equal amounts of mono- to tetraesters, and HLB 1 about equal amounts of tetra- to heptaesters according to THIS publication). -> Question @MarkBroussard: Which sucrose stearate are you referring to?
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Colloidal oatmeal: That reminds me of vegan milk alternatives which I regularly use for my protein shakes (I’m not vegan but milk gets “sour” in my shakes). These, not just the ones with oats but also rice, almond, soy etc. are colloidal suspensions. Out of convenience, I’d simply use one of those drinks if I felt like putting delicious food on my skin
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@saraahsan The way you describe it, it’s clearly an issue with iron induced fat oxidation = super fast rancidity/oil gumming like it happens with linseed oil varnish and oil paintings.Ditch grapeseed oil and your problem might be solved. If not, switch to fully saturated triglycerides and ester oils.
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It’s not just fill temperature but temperature difference between cream and lid/exterior in general. Because the lid is often the thinnest part it cools down faster than the pot/cream base and cause water vapour to condense. This can even happen in a fridge just because of temperature variations between of less than 1°C. It can also go the other way round and the condense droplets may disappear again should temp rise or you find yourself with water droplets on the cream.This effect is what we call sweating and happens more often with creams containing high water activity such as cold creams (those without emulsifier or just small amounts thereof), emulsions of a “swollen oil phase type” (high lanolin), and other types which are basically stabilised by a high melting point oil phase (high wax or hydrogenated oils) rather than emulsifiers and contain few to no water soluble ingredients/humectants. Hence, this phenomenon can also be an indication of poor preservation in case one uses a hurdle approach (especially with o/w emulsions) or that your emulsion is not perfect and contains “water pockets” (obviously only the case with w/o emulsions and borderline lamellar/mixed types).I’ve seen it (today actually too
) mostly with simple pharmaceutical base creams which are stored in the fridge and are either taken out regularly or the fridge is used regularly = a lot of temperature fluctuations, no humectants or water gelling agents in there, and low amount of emulsifier but thoroughly gelled oil phases. -
Bad formulation skills, bad choice of storage conditions…
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Benzylic acid is a preservative and bitter almond oil a perfume.Glycerol and sorbitol are both humectants; the latter is solid but usually used as aqueous dilution with similar properties than glycerol.Take some clay and simply add glycerol until you get about the consistency of your bench-mark. That gives you the overall content of glycerol/sorbitol. Now replace bits of glycerol with sorbitol until the feel of your mask fits your needs.
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@ngarayeva001 So true!PS I’ve got a tag so people could see that I’m NOT a cosmetic chemist but one with scientific background. Folks here seem to be ignoring that tag…
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Dexpanthenol is the natural enantiomer (can also be obtained by synthesis) whereas D/L-panthenol is of synthetic origin (cheap synthesis).For skincare, biologically fully active dexpanthenol is preferred whereas on hair it doesn’t matter (since hair is dead) and hence, the racemic mixture is of higher economical importance in the latter case.
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Good to hear that you found a solution for your problem!
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That’s what your skin will tell you! There is no “in the books” limit (well, probably below 2 and above 12
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If it’s only the iron oxide ones, then you’re making varnish out of your oils.You have two options: Take a different iron oxide quality or a different oil base (less unsaturated fatty acids). Grapeseed oil is the most likely oil which polymerises/goes rancid. Remove/replace that and try again.
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Naw, I’m not using silk amino acids but just plain pure amino acids, nothing to do with silk .
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I can’t remember which brand it was that uses real silk for hydrolysis (probably Shiseido or Kanebo/Sensai)… I wonder why silk peptides should be any good. I prefer pure amino acids and these are usually derived either from plants or petrochemistry. If you choose wisely, these AAs don’t smell once in solution and have real nice humectant activity (and are cheaper than silk).
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1) Who says it has to be in that range? It seems as a logic deduction but there’s enough evidence that there is no “must be”.2) You’ll get for example pimples, rashes, or itchy skin if your cream is out of the “healthy” limits.3) Fading like bleaching or like reduced pigment formation? pH will affect ascorbic acid stability and reactivity and hence its antioxidative efficacy. But this is during storage. Once it penetrates skin it will depend on skin pH. Skin pH in this case is not on the skin sebum pH but the pH in the corresponding skin layer. Changing that one isn’t just dependent on pH of an applied product but also (or even more so) the quantity of pH active substances and composition such as compounds which change pH between and/or within living cells due to mechanisms other than their inherent acidity/alkalinity.4) Living cells are self-regulating and the intracellular pH will always be the same. Therefore, pH of a preparation doesn’t directly affect the effect of retinol (which, assuming it’s metabolised to retinoic acid, acts as nuclear factor) but pH and the whole composition of a product might interfere with pharmacological activities of retinol/retinoic acid by different means. There is no simple answer and it’s not just about high or low pH.
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1) Skin pH isn’t fixed and depends on a lot of factors including under others ethnics, climate/season, age, test method/lab, tested area (face, extremities etc.). Whether or not it needs to be slightly acidic is not fully understood though sebum composition points towards a naturally acidic pH.2) Your skin will tell you within a few days of regular usage.3) Depends on which effect you’re referring to.4) AFAIK not regarding product stability. Effect-wise it doesn’t matter as long as retinol penetrates deep enough.5) Again, depends on the effect you’re hoping for.