Pharma
Forum Replies Created
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zetein said:Why p-hydroxyacetophenone isn’t considered a “para-ben” ? lol
Because it’s not a benzoic acid derivative.Or are you simply making bad chemistry jokes because all the good ones Argon? Maybe start with more basic stuff, like jokes about sodium hydroxide?
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Perry said:Generally, regulators ban ingredients that aren’t used very often…Or they are to some degree harmful to users and nature and are used in many different products of many sectors and are produced in huge annual tonnage. One of those rather rare examples is borax and boric acid (in Europe).It certainly is easier to ban a useless or rather non-profitable product just so authorities can keep up their rate and don’t have to bother with layers which usually accompany any lucrative product… we’re currently in such a situation here in Switzerland where economics and lobbying easily got reason and safety swiped off the table and where they didn’t, pharma layers are keeping the status quo for two years by now, two years of millions of $$ (or rather CHF) of income for pharma industries, and the sales reps are even proudly bragging about it on how long they are likely to get the game going even though everyone knows that there will be a change because officially and according to law, it has already been decided. But what am I complaining about our little issues in our little country when you, my dear friends from the States, have a president with more than one such trump card up his sleeve (pun intended).
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As far as I did follow the paraben story, methyl-, ethyl-, and propylparaben will not be banned due to their sufficiently low lipophilicity.
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There are also special silicone emulsifiers most of which are silicone-derivatives themselves.Which one will work depends on what exactly you’re doing, like w/si or si/w, type and amount of used silicone… so, there is not ‘the best’ emulsifier but maybe one (or several) which is great for a particular formulation from a particular formulator for a particular clientele.
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Pattsi said:…
Anyone heard about the price? If it will cost me up to $1,000-$1,500 , I would rather not.
…The version only with the homogeniser attachment costs around $ 300 if purchased in Europe from an official retailer.
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- Methyl- & Propylparaben or sodium benzoate & potassium sorbate for pharmaceutical preparations (made on prescription at the pharmacy)- Verstatil PC (phenoxyethanol & caprylyl glycol) for trial formulations- Dermosoft 1388 eco (sodium levulinate & sodium anisate) plus glyceryl caprylate plus pentylene glycol plus Magnolia Extract 98 for everything else. Stupid thing is, that cocktail seems to negatively affect viscosity and even break certain emulsions.Obviously, I also add a chelate (phytic acid or EDTA) and antioxidants (different ones, depending on requirements).
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In my experience, LaraCare makes emulsions feel drier, less tacky, and less oily once applied. However, it forms a film and that one might reduce TEWL although the film itself doesn’t feel hydrated or moist. It’s more a ‘rough’ velvety film, hard to describe, which I think has potential though my wife really doesn’t like its feel.Bottom line is, I wouldn’t consider LaraCare a moisturising ingredient, rather the opposite. On the other hand, it might be used to mask negative impressions (tack, stickiness, gloss) by too much added moisturising agents.
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Which butanediol are we referring to here? 1,3-butanediol, although by proper definition not a glycol, is the most often used isomer but by far not the only one. Apart from that, butanediols also come as stereoisomers which complicates things even further.1,4-butanediol certainly is problematic because it’s quickly metabolised to GHB. Therefore, it is a prodrug or at least a precursor and therefore regulated.
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@Bo77 Thanks for the warning. I’m less interested in it as stirrer but mainly as homogeniser (however, would have been great if it did both). Homogenisers may kill polymers if you overdo the mixing by homogenising for more than just a few minutes. I’d guess that cheaper tools are safer because of a larger gap between rotor and stator.@suswang8 I considered the Rotilabo tool as alternative to the Chinese tool. Carl Roth is a renowned company with good quality products. I decided against it because it’s a hand held tool and made for rather small quantities. It’s likely not going to work with a normal drill machine, because it’s a rotor-stator attachment and there is no point in spinning the outer part and letting the inner just hang there (or vice versa).
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I decided against stick blenders when I stumbled upon that crap cheap Ultra-Turrax-like Chinese knock-off thingamajig. I ordered it a few days ago.I wonder whether or not it will be any good or last long… likely not useful for more than 1 litre but that’s fine with me and probably not doing well with high viscosity emulsions (not so fine with me).I’ll keep you in the loop.
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Don’t get me wrong, I’m not saying those ingredients aren’t safe. I just don’t like them (true, MIT/MCIT I really don’t like and avoid if possible, they’re already in so much stuff which one can’t avoid…) although SLES and PEG-derivatives are very efficient and so far safe. SLES can be a bit stripping but there are many workarounds for that issue if you consider it an issue.
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Okay, so you tested it for a long time on your own face. Wouldn’t it be up to YOU to tell US whether or not this formulation is any good? I mean, how the heck are we supposed to know how YOU feel after applying that cream on YOUR face for MONTHS. At least show us a before-after picture! :smiley:
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Well… errr… there are several different Polawax varieties available. They’re commonly PEGylated and PPGylated fatty acid derivatives. PEG and PPG are derived from mineral oil, so is your preservative and sometimes certain B vitamins such as niacinamide too. Hence, your claim doesn’t add up.Mix it, try it and see if it’s stable and how it performs
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I’d take the ingredient ‘facial cleanser’ as fall guy and go with something without SLES, PEGs, and isothiazolinones :smiley: .Reasons for this can be found in several of my other posts.
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You can switch that for (and the wax) any hydrogenated oil or high melting point wax or whatever. All you need is a gelled oil phase or the emulsion breaks.
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Given slow reaction times, triethyl citrate should work fine.Can’t access that link at the moment… citric acid does react with zinc oxide to form zinc citrates and obviously, that one is more effective against microbes . A publication doesn’t mean the two chemicals are ‘cosmetically’ compatible. I’ve read enough rubbish papers to know that just because people see an effect in the lab doesn’t make it true and just because people publish something doesn’t mean that they’re intelligent beings.
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@biofm Are you considering to include one of your ionic liquids? IMHO this might actually work though I’d rather try deep eutectic solvents first… you’d just have to find one which is stable enough at alkaline pH.
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Although assimilation via hair follicles is known/claimed for certain substances, the amount of amino acids does not suffice to show any effect at all. These are pure claim ingredients to boost marketing, nothing more.
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Amphoteric? How so?It’s nearly insoluble in water but not entirely insoluble (especially with qualities which contain traces of carbonate and hydroxide). So, zinc oxides often react alkaline. Given that it’s a metal oxide, it will react with acids and is therefore incompatible with these. Without water, i.e. in pure oil formulations, there is by definition no pH, no matter what you add (unless it’s a protic solvent or the like).
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If it foams, it’s likely sodium carbonate, a no-go these days .You don’t ‘reduce’ too acidic pH, you neutralise it. Reducing pH usually means lowering it and that means making it even more acidic.Sodium hydroxide, TEA or free base arginine should work without foam.
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LoL, yea, that’s one of my publications (the officially best, I guess).The link to the lecithin page is actually one I used too when starting to work with lecithin . The PC I worked with was under others purified according to the mentioned protocol although I did use boiling dry ethanol to dissolve acetone-deoiled lecithin, cooled it down to -50°C and then centrifuged the heck out of it (and repeated the process twice again). For practical reasons, go with 96% EtOH, -20°C (household freezer) and whatever centrifuge you can get. Filtering will not work, the stuff will clog everything. Just letting it sediment can work but takes an awful lot of time and you lose a fair amount of PC in the sediment.Pure PC is great for liposomes/vesicles or mixed micelles whereas deoiled lecithin is way better for most other (cream related) applications.If you feel experimental: I also synthesised ascorbyl palmitate (synonym: palmitoyl ascorbic acid) for so called mixed aspasomes (liposomes of PC and ascorbyl palmitate). Quite easy if you have concentrated sulfuric acid, ascorbic acid, palmitic (stearic works too) acid, and an apolar solvent such as diethyl ether.BHT works too.Regarding suspended vs. vesicles: High amounts of vesicles require a bit more than just dumping PC into water. Doing so results in a mixture of a lot of things, a small part vesicles but also other structures. Hence, suspension is a more appropriate description of the result.I’ll keep that thread on my ‘to do, but later’ list .
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It’s harmful, that’s a proven fact, though it depends on %. 1-2% should be fine but due to the potential risk, it’s not advised (here in Europe) to just use it like that as cosmetic (for beauty) but rather as pharmaceutical drug (against certain skin diseases).
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I’ve tried polyglyceryl-3 oleate as co-emulsifier with Isolan GPS. It’s refattening… that’s all I can say from my little trial. Stability wise… not sure. The advantage of combining the two is that one is a ‘fast’ low molecular weight emulsifier (easier to emulsify) and the other a ‘slow’ high molecular weight one (higher long term stability). Working with the two is somewhat challenging because they have different optimal salt concentrations, different requirements for oil phase viscosity, and so on. Only using sodium lactate and PCA didn’t do the trick. Cetyl alcohol and cetyl ester form lamellar networks; these contradict the action of such w/o emulsifiers and may not work well. I had separation after several hours to days… just the time it usually takes for these to diffuse into the water phase and form lamellar networks. Not sure how well your silicone emulsifier will take these additives.Bottom line is: Your silicone emulsifier is a polymeric one and hence, a combo with low MW P3O seems reasonable though you will have to play a bit with the other ingredients. Apart from that, Evonik has nice base formulations which are great starting points and nice inspirations such as THESE.
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Just a shorty here:What you have is lecithin. To call it phosphatidylcholine (PC) or the like would require higher purity. Lecithin is, for magical reasons, completely insoluble in acetone and hence, acetone stripping is standard in the production of deoiled lecithin. PC is soluble in cold (and more so in hot) ethanol whereas most other phospholipids are not soluble in cold EtOH.If you’re a fan of traceability, name the plant source if you feel like it, else just call it lecithin.The culprit of rancidity are the polyunsaturated fatty acid chains. A chelate will only do so much, you also need a fat soluble antioxidant (e.g. tocopherol, best combined with ascorbyl palmitate).Alternatively, use fully hydrogenated lecithin…. it’s not going rancid as fast but that does not contain any unsaturated fatty acids and hence, may not help you.Metabolism of lecithin from topical application is a matter of debate. However, lecithin is water suspensible which gives it certain perks compared to other oils.Don’t have time for more today, sorry.
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BTW if you use above 74% (by volume) of inner phase, you’ll get a so called high internal phase emulsion (HIPE) wherein the inner phase (water droplets) become less round and distorted. Adding even more of the inner phase increases droplet deformation and hence increases viscosity. That’s where the ‘more oil = lower viscosity’ comes from.Apart from common table salt, magnesium sulphate is commonly used in w/o emulsions. It is a near requirement for stability. The reason behind it has to do with salting out effects and surface charge neutralisation leading to a higher o/w distribution coefficient (the emulsifier becomes more lipophilic or, if you’re a devotee of HLB, HLB gets lower which is said to push an emulsion more to the w/o side and away from o/w). Every formulation and every emulsifier has an optimum salt concentration and every ionic solute counts though usually a lot less than NaCl and MgSO4.Apart from that, you can get inspirations from other similar emulsifiers such as Isolan GPS.