lmosca
Forum Replies Created
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@Fekher, yes, it seems that the Canadian list has some evident mistake (or maybe RB sells a completely different hand sanitizer in Canada that we are not aware of).
Dettol is known to use chloroxylenol as the main disinfecting ingredient.
However, the 4 products mentioned in your picture (I assume taken from their UK website) all contain benzalkonium chloride (which has a limited virucidal activity) and not chloroxylenol.
Chloroxylenol is not virucidal.
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@Fekher, if you are referring to Dettol brand hand sanitizers, then those are alcohol based as all the others.
If you look here:
http://www.rb-msds.com.au/product/product_display.aspx?intProductID=14
you can find all the SDS for the Dettol products.
The Instant Hand Sanitizer is isopropyl alcohol-based.Also, on this other website:
http://www.rbnainfo.com/MSDS/CA/DETTOL%C2%AE%20Antiseptic%20Liquid%20EN%20GHS%20CA.pdf
you can find the SDS for the most common antiseptic/disinfectant product. The SDS clearly states that this product is not intended for use on skin. -
@em88 To add to what Perry wrote, Robert Lochhead is for sure one of the most prominent figures in rheology modifiers and polymeric gelators for the personal care industry (and not only that). He was chair of the Department of polymer chemistry at the University of Southern Mississippi (which is probably one of the most prestigious polymer schools in US), where he is now emeritus professor. He was also president of the Society of Cosmetic Chemists, and before that he worked for BFGoodrich and Unilever. So he is definitely not uninformed on the topic.
@Perry, this is a link to the first patent that mentions quick breaking upon contact with skin. https://patents.justia.com/patent/5004598
While it is mentioned several times, there is no reference to further data to support this.
In other words, yes, quick break of the gel with concomitant loss of viscosity does happen on the skin. As to why, there is no explicit support data that it is caused by electrolytes from perspiration. Other things can influence the viscosity of the gel, like the surface temperature of the skin, or the shearing when pumping/moving/rubbing, or all three of those parameters.Unfortunately we are in the murky realm of industrial intellectual property protection, patents etcetera… Disclosing full data is not something that companies do, because it may hinder future patent protection or loss of market due to a competing firm.
What I mean is, this data might be existing somewhere, it’s just not public or passed by my radar.
This (the gel quick break) is not a simple problem, and it has, as it stands, 4 different variables to isolate (in reality there will be even more, like pH, type of polymer, concentration of every component in the formula, and so on). Just the design of control experiments to get a real answer could be a massive enterprise, in terms of capital, for a medium-large sized company.
And that is just to try to identify the stimulus (input/action) - response (output/reaction) side of it.
As for he why, that’s a different story altogether. Knowing how something reacts and to what, doesn’t necessarily mean why it does/doesn’t work. For what concern gels (polymers or low-molecular weight) I can say for direct experience that there has been a constant improvement in the knowledge of why things work a certain why in gels. However, I feel we will still have one or two lifetimes in front of us before we can fully understand all of the detailed intricacies of gels.
In other words, if we compared emulsion technology and emulsion science, both mature, well developed fields, with gel technology (the how to), would be considered a 21 years old, and gel science (the why) would be an elementary school kid.I do agree with you. I wouldn’t dismiss Lochhead’s opinion. But it just sounded strange, and too simplistic, at first.
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Dettol contains, among the putative antiseptic (chloroxylenol), isopropanol and pine oil. Albeit at <10% each, those can kill viruses as well.
Pine oil has shown virucidal activity against enveloped viruses (mainly by dissolving the envelope).If you look at list N from the EPA for covid 19 approved surface disinfectants, https://www.epa.gov/pesticide-registration/list-n-disinfectants-use-against-sars-cov-2
You can see that pine oil and chloroxylenol are not even appearing on the list.
Thymol can be used to disinfect, and it is very formulation dependant.The way this is assessed, so far, is not direct activity against coronavirus, but through a historical test of what kind of viruses, similar to coronavirus, are eliminated with said disinfectant.
On an extreme, it is a wishful thinking experiment: we’ve seen it works for A-through-T, so it should work for U.
That’s the reason all disinfectant say that it kills 99.9% of critters, because in that 0.1% remaining, you have got potentially thousands of different pathogens that have not been tested. Out of a 1000, your product will likely kill 999. Out of the remaining 1 pathogens, that disinfectant will inactivate 95% of it.
It’s that 5% of one pathogen, out of the thousand different strains and species that have not been tested, which constitute the 0.1% of all pathogens, that your company will be held liable for in the court of law, if you had said your product is 100% effective, and yet somebody got infected.There are currently no resources to test all disinfectants to covid-19 on all surfaces. So we have to go by analogy/similarity.
If you look at those tables, you can see how the required contact times are long (10 minutes or so), because those actives are used at low concentrations because of their irritancy / corrosion potential. That’s part of why they work, and why they are used on surfaces instead of skin.
As @pharma said, those are products that have been tried and tested and are produced by companies that could be liable for millions, if not billions lawsuits if they didn’t do their job properly.
As for us, we do not have the resources to perform such testing, nor the time to try it. So we must go with what is a) available to us, b) it is tried and tested.
That gives us very few options: hydrogen peroxide, bleach (for surfaces), alcohol (for hands). Oh, and soap! -
@steamedrice, I am not a formally trained cosmetic chemist.
I am, by education and training, first an inorganic chemist, who then became an organic chemist. That’s what I do for a living now. I’ve worked on sensors and supramolecular gels. Now I am working on self-assembly, self-replication, molecular machines and systems away from equilibrium.
All that I’ve learned about formulating, I’ve learned through books, articles, and places like this. Having a formal education in chemistry is perhaps an advantage, I consider myself very fortunate because where I received my education from, classes and labs that teach you about industrial chemistry, pharmacology, emulsion technology, and other related topics where free to add to anyone’s curriculum. More than fortunate, my university had a uniquely powerful pharmaceutical chemistry department in the whole country.
Eventually, about 4-5 years ago, I felt ready to start buying equipment and ingredients. I still do my 10 hours of chemistry in the lab, and formulate stuff in the evening, or read mostly scientific publications (cosmetics and not). -
@em88, it is not as illogical as it seems.
It might be true if ethanol (or IPA) were in the discontinuous phase of an emulsion.
This happens with oils and gel emulsifiers, where the oils are dispersed as the discontinuous phase in a O/W colloid. In order to form a film, the oil droplets need to coalesce.
Now, if we would translate this to a hypothetical alcohol/water colloid (mind, it does not exist, as alcohol and water are fully miscible) this “gel breaking” would make sense, as we know that we need to achieve a certain local concentration of alcohol for it to be effective at sanitizing.But it is not a real scenario. Hand sanitizers are not proper emulsions, with discontinuous/continuous phases, yet, from the chemical point of view, they are not homogeneous mixtures, because the gel network constitute a separate phase that is in equilibrium with the sol phase. The concentration and activity of alcohol is the same, within statistical difference, whether as a liquid or as a gel.
If there is a difference between the two, we will never know why, because a control experiment will require removal of the gel phase, but that is exactly what we are trying to show.
I’ve whipped together a 75% ipa gel with Sepimax Zen (1.3%) yesterday. Quite unsurprisingly to me, it behaves just like in the video. There is a layer of “more liquid” gel at the interface between the glob of gel and my hand, and if I swish it around, it liquefies. This is exactly the same effect on:
I) unwashed hands
II) hands washed with soap and dried with clean towel and air for 2 minutes
Thus taking into account the presence of electrolytes from my palm perspiration.I’ve checked the whole of R. Lockhead publications, and the only publications on this topic are relative to O/W coalescence. He has done plenty of rheology of gels in presence of electrolytes. But there is no mention of its effect on sanitizers.
It doesn’t help much that 50% of its publications are abstracts from conferences, which are scientifically irrelevant. -
SCI is just not soluble in cold water.
The solubility @25 °C is 0.01%.If you can, switch to Ammonium cocoyl isethionate (ACI), which is supplied as a solution.
Otherwise you’ll have to use a co-surfactant to shift the solubilization equilibrium to the right place. CAPB is perhaps the most used for this purpose.
I remember from a paper that a mixture of Polysorbate 20 and 80 (10%, 15% respectively) can solubilize 7% of SCI.SLS and SLES do not solubilize SCI (at 10%, they solubilize less than 1%), so SCS will not be different from those.
Alternatively, if you have them at hand, you can use a 1:1.5 weight ratio between SCI and ammonium lauryl sulfate (ALS) or ALES (or both). The excess of ammonium ions in solution will screw up the thermodynamics of the SCI lattice formation.
If you want a facial cleanser, then you can formulate up to 30% of SCI with 10% of an emulsifier (polawax, e-wax, to keep it cheap). This should give a lotion-y like opaque cleanser.
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@Perry @ngarayeva001
I do not think the video is telling a full story, particularly when it says “it releases alcohol”.
Alcohol is the solvent, it’s not ab-/ad-sorbed by the polymer (like it would on a sponge). The formation and disruption of a gelation network is minimally influential on the activity of the sol phase.Activity of the solvent changes only in proximity of the gel fibrillar network.
In most cases, the formation of the fibrillar network is adjuvated (and dependant of) the solvent.Most hydrophilic polymer gelators have a very large and negative hydration enthalpy, thereby indicating that they are stabilized by forming ionic and hydrogen bonding interactions with the solvent. In the case of carbomer, this is even more true, as the polymer itself is a polycarboxylate (ionic).
Most of the solvent (water and ethanol) will not be partitioning into the fiber-network. In fact, most of it will be the bulk of the solvent, with only a minimal fraction being “adsorbed” by the fiber-network.
Hence, the bulk of the ethanol will still be ethanol (or isopropyl alcohol), with exactly the same activity as a non-gelled solution.Furthermore, I am skeptical about the amount of salt referred to in the video.
It takes a few seconds for a pinch of salt to act on the gel, while it takes almost no time for the gel on the hands to liquefy.
I doubt that the amount of electrolytes on our skin (or their activity) is such that it behaves like a concentrated NaCl solution.
Temperature difference and shear-thinning would be my first culprits. -
For surfaces there are plenty of viable non-alcoholic sanitization methods, chemical and physical.
UV light, superheated steam are two of the most common physical sanitation methods for flat surfaces.
Chemical methods can vary and are very much dependent of the surfaces you will sanitize.
- Bleach and hypochlorous acid - corrosive to metals, can yellow plastic laminates, smells like overchlorinated pool (love it, personally).
- Formaldehyde, formaldehyde formers (the first abandoned in most jurisdictions, due to volatility and toxicity.
- Hydrogen peroxide, non-corrosive, doesn’t leave residues, shelf stability of concentrated solutions is not great, usually used at lower concentrations. With acetic acid or formic acid forms peracetic and performic acid, which are great germicides.
- Organic germicides, like chloroxylenol (dettol, in some countries), benzalkonium chloride, biguanide-based, etc… good on surfaces, usually require longer contact time to act, and sometimes they have reduced activity depending on microbial load and/or in presence of other organic debris. They are not omni-potent against spores or viruses.
- Here in the US we have access to a concentrated product called Star-san (Fivestarchemicals). It is good on most surfaces (but not metal) and does not require rinsing. It is a mixture of phosphoric acid and sodium dodecylbenzenesulfonate. It is used for sanitization by homebrewers and even by some cosmetic diy-ers.There are even more, but this is what I could think on the spot.
The main questions you want to ask yourself is:> What do you want to kill (molds, bacteria, viruses, multi-spectrum)
> How fast should it be?
> How toxic is it to humans, animals, and how harmful for the environment?
> Which kind of surface is it compatible with? -
It is not as easy as taking a liquid product and just removing the water, compress it into pellets and pack into bags or compressed tablets.
Many products actually contain ingredients that are liquid (think about glycerin, or emollient ingredients like short chain glycerides, esters etc…)If you refer to soap, then you do not have much choice, as the definition of soap is “alkali-metal salt of fatty acids”. Dissolving, say, solid potassium cocoate in water just doesn’t happen without hot water, mechanical stirring, or waiting geological times.
Syndets are usually more readily soluble (aside from a few that require co-surfactants, of which SCI is an example).
Among technological challenges, the first is the protection of your formulation from moisture, moisture is the enemy of powders. If you want to mix in humectants, hydrophilic emollients and so on, those are tendentially highly hygroscopic. You will have to use impermeable bags or sachets. Even those, over time, will let moisture in, the product will cake into a “solid” stone, or into a honey-like saturated solution of your formulation.
The finer your solid, the faster it will dissolve. Thus, microbeads <1mm or finer powders will be preferable to pellets. If opting for microbeads, or tablets then a dispersing agent is needed (modified celluloses, povidones, or disintegrants like citric acid+bicarbonate).
If you use powders, then anti-caking, flow agents are needed (silicates, for example).
I am not a big fan of such products, in general. One issue for which there seems not to be much written about is preservation. Unless the pH of the final product is alkaline or very acidic, the product will not be preserved once diluted with water. You may want to add preservative in the correct target percentage to the powder/bead/tablet, but some may lose efficacy by decomposition, reaction, or evaporation.
Then again, you have the customer side. And customers don’t follow instructions. One of them might decide to use spring water from the well to dilute your powders, that will be far too much of a bacterial load for the preservative to be effective. Another one will use tap water, with high dissolved calcium and magnesium salts, and perhaps some dissolved iron, that will cause (a) precipitation of fatty acid salts (soap scum), and (b) premature rancidity of ingredients (iron ions). Another customer will decide to save money and the environment and dilute your formula twice the required amount (or save half packet for the next time) and your preservative will not be effective.
The bottles that most companies seem to use are made of glass (great for recycling, multi use, yeah!). Which is fine for something that sits on the sink. Definitely not something you want to keep in your shower, where it can slip off your hands/caddy, and shatter into tiny little razor-blade sharps on which you are going to step/fall on.
And this is only for hand-soap / shower.
You cannot make a lotion/cream without some kind of high-shear. Solid products needs to be melted for the emulsifier to work. You need at least 2000 rpm stirrers to produce stable emulsions (with traditional emulsifiers). And if you want to avoid the need for melting stuff, cold emulsifiers require ingredients that are liquid, or readily soluble in either water or oil phase to work properly (and still need some stirring and shaking). Again, the preservation problem will be even more stringent, as in a lotion, with water, you don’t have much leeway in terms of pH adjustment, and you have a lot of germ-food in there. Then there is the fact that you’ll be re-utilizing containers. This is against any good manufacturing practice (where containers are sanitized or sterile, water is purified and/or sterilized, equipment is thoroughly cleaned, and every single documented protocol maintained as clean/traceable as possible).
There are too many things to consider, and 90% of them are things that you can barely control from the customer side. You better sign up for the best liability insurance there is out there. Your formulation is only 10% of the success of your product.
IMHO, a bar of soap, or a syndet bar (that with few modifications can become a solid shampoo), have the same environmental impact as what many startups are trying to do. And I don’t know of anyone who used a bar of soap incorrectly.
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We receive our 200 proof USP ethanol in HDPE bottles. Should be fine and doesn’t carry the risk of shattering like glass if inadvertently dropped.
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Bentonite clay is a known irritant.
It is mildly alkaline, that can exacerbate certain skin conditions, strip the acid mantle. It seems that your pH is fine at 5.
Did you measure it before or after mixing in the clay? Or immediately after mixing it in? If so I would let it sit and monitor the pH of samples at regular intervals over 24 hours, to see if there is any drift.Does the redness happens with the same frequency if you used only Kaolin, or very fine french green clay (which is a montmorillonite of different origin)? Both are lesser irritants than Bentonite, with Kaolin being the more “delicate” one. (Nevertheless, clays are “brutal” ion exchange and absorbing agents, from a chemical point of view).
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@raiyana, would you drink bleach?
Seriously, if they claim you can drink it, then it’s probably just salty water.
You say there are 300-500 mg/L of chlorine, that would mean 300-500 ppm of chlorine. Dilute it 10x and you get 30-50 ppm.
Well, the CDC says that up 4 ppm of chlorine is safe for consumption, and that is the target level used for tap water.
https://www.cdc.gov/healthywater/drinking/public/chlorine-disinfection.htmlYou will be drinking something that is 10x above the safe consumption limit. That person that told you so should receive a visit from the FDA asap and receive a public flogging, for all that I care (or whatever institution regulates these things in other countries).
That is, if you still had free chlorine in it.
Unfortunately if you read this paper, solution of hypochlorous acid at pH 6 in pure water are stable for a few days, (closed container) and when exposed to light, only a few hours.
https://www.jstage.jst.go.jp/article/bio/22/4/22_223/_pdf/-char/enThen there is the mixing / dilution with 9 parts of water. Everything that is the water (if you didn’t have milli-Q water) will react with hypochlorous acid and decompose it even faster.
So yeah, most likely, everything you have is just some salty water.
Is it safe to use on skin? Probably, just like bottled water would.
Is it effective as a hand sanitizer? Not likely, unless you used a solution that was produced within a few days and hasn’t been exposed to sunlight or UV light and has not been opened to the air for long periods.
Is it safe to drink? Again, would you drink bleach? You probably only have a bottle of salty water, but why would you risk it?
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Well, it is just another (fancier) way to produce bleach in the same way it was produced for a century via the chloralkali process. The process seems to mention to be able to control the pH of the final effluent, but it fails to me to understand why, as at the cathode you will generate sodium hydroxide.
So yes, bleach is definitely one of the most poweful sanitizers out there (I love bleach!). As for its use as hand-sanitizer, I would not, unless it’s the only liquid available in a 25 miles radius.
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@amitvedakar, all long chain quaternary ammonium salts are moderate antiseptics (think about cetrimonium, or benzalkonium).
They mainly operate by cell lysis and exhibiting some surfactant activity (albeit they are used at lower concentrations than you would if you’d use them as surfactants or emulsifiers).
They work best against bacterial, amoebal, algal, and fungal contamination. They can be active against some viruses, especially when combined with other antiseptics, however, they are not recommended for gram-negative bacteria. -
If you want a balm / paste consistency, use E-wax or Polawax. They are cheap and readily available. You can control the consistency of the final product by using cetearyl alcohol and stearic acid (use more for a paste, use less for a balm like product).
You can boost the rinse-off by adding polysorbate 80 (again, dirt cheap).I would start with 15-20% of the total lipophilic fraction (oil + fragrance + thickeners) and see how it feels from there. If you boost with polysorbate 80, take off the percentage from the emulsifier.
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@ngarayeva001, definitely not. At that pH phospholipids and glycerides will start to saponify, proteins will denature and their chemical structure will be irreversibly changed by hydrolysis. Even so, with some much TEA, the solvent effect will probably be as important. Lipophilic stuff will likely be dissolved. TEA has a dielectric constant of around 7, which is comparable to that of ethyl acetate, so it will be extremely de-fattening.
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@Pharma, and the advantage is that it increases in mass as you incorporate dirt, phospholipid membranes, glycoproteins, and more gross stuff. After a couple of days, you can split it in half and give one half away to your friends!
Oh boy, I am having a bad day. I need some levity.
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According to what you have there you are using:
4.4 % carbopol
12.3 % TEA (are you using pure TEA? :#)
13.7 % glycerine (ick)
4.4 % fragrance (it must smell like a floor cleaner)
65 % aloe.I am surprised it does even look like a gel, I would say more like plumber’s putty.
Post some real percentages if you want some feedback.
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@Pharma, likewise!
That’s what surprised me as well, I’ve ordered the paper, just to satisfy my curiosity.
My idea of elimination would be enolization-like. Whereas enolization is very fast in a system like that, and even more so in a protic solvent, thanks to the protons available to be exchanged, it does not rule out the possibility of trimethylamine (fishy smell) as a mediocre leaving group.
pH= 7 was only a guess, I’ve actually checked the pKa of TMG and it is 1.8-1.9. The enolization would happen on the carboxylic acid, and, only with more difficulty on the carboxylate.
Ah, mix some sugar in, some people might like a lotion with “pot roast” scent! :smiley:
Pharma said:Also, replacing the quaternary ammonium compounds with amino acids results in an array of unfortunately too often not very pleasant scents due to Maillard type reactions (for non-chemists: that’s the reaction between amino acids and sugars which happens during cooking/baking and gives for example bread crust, grilled meat, or roasted coffee their typical flavours). -
@Pharma agreed, that is not the case, however some of the keywords for the paper refer to Hoffman elimination. Trimethylglycine would be a powerful substrate for a unimolecular elimination, assisted by the enolization of the alpha carbon. If so a pH shift toward a near-neutral to mildly basic, and a 10-15 degrees increase in temperature can accelerate this reaction in a non-negligible way (temperature alone would double the reaction rate every 10 degrees). Unfortunately solid state reactions are far more different than in solution.
I believe the precaution to be only that, and nothing more, but I would be careful if I were nearby pH of 7. Should you smell fishy, that is the sign that trimethylglycine is getting degraded. -
@Pharma and @Zink,
this paper’s abstract:
https://link.springer.com/article/10.1023/A:1019931016615
seems to say that both the anhydrous and hydrate form are quite stable.Even I cannot access the full text, but if interested, I can try request it through interlibrary exchange.
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Interesting.
How would the compliance of the manufacturer to cGMP and FDA regulation be ensured in this case? Especially for the resale of “artisanal” products. I guess most of them in the shaving category would be shaving soaps, but what about shaving balms, aftershaves, etc…?
What’s the practice in this case? How does one report these kind of things to the authorities? I know it’s possible to report reactions to food/drugs/cosmetics, and it’s possible to tip FDA about unsanitary practices in the food industry. But what about a business with potentially regulatory issues visible from far away?
Cheers,
L. -
@Pharma and @Perry I do read their blog posts constantly and I have been inspired to try some ingredients. It does seems that they have a quite good grasp of chemistry and scientific basis, and yes, I also found the “Chakra” name a little confusing and upsetting first. They try to explain some basic formulation chemistry in occasional blog posts, with layman approach, which I find worth of praise.
If anything, I find their formulations too “baroque”, with very long lists (dozens of so) of oils and extracts, at very low percentages; but I am a minimalist. They recently jumped on the MyMicrobiome wagon, for which I have not read enough to comment upon. It could be the next thing, or the most recent fad… I’ll leave the judging to the professionals.@PeaceLoveOrganics, everyone has a hippie dippy in their family. I have 15+ year of research in chemistry (not cosmetics), yet this forum is a great resource where I learned and still learn new things every day, mostly lurking, seldom participating. For once professionals, to-be-professionals, veteran hobbyists, and beginners have the chance to ask, answer, and learn from people who have decades, if not hundreds of years of formulating experience combined. Science can be learned, and it’s only through experimentation and reproducing results that people learn the proper tool of the trade, and to make safe, reliable, and honest products. I only wish more like you would ask these questions on platforms like this.
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Soap acts on SARS-CoV because their capsid is held together by a viral envelope.
The membrane is destroyed by soap (just like by any other detergent or solvent, like high concentration of ethyl and isopropyl alcohol) because it is just a phospholipid bilayer with some glycoproteins.One of the reasons why antibiotic agents do not work or work poorly is that viruses are not living, you cannot disrupt their function if their only function is using a host cell to self-replicate.
That’s why virtually any good sanitizer has surfactants. Those rip apart membranes of things like viruses and non-encapsulated bacteria. Then, high or low pH, or low water activity will cook the proteins to a mush, and eventually the genetic material will start degrading as well.
The only difference here is how the method of application works.
Biocidal and viral inactivation requires a “contact time” to be effective.
Alcohol based products need high concentration of alcohol because alcohol evaporates quickly (rheology modifiers help by slowing down evaporation).
Anything below 60% is ineffective because it will require too long contact time before it can destroy the membranes and that will be unpractical.Alas, it seems that the worst are foaming liquid syndets. Why? Nobody knows yet, but there seems to be a correlation (unconfirmed yet) between the efficacy of those vs. syndet bars. In the order: Soap > Syndet Bar > Liquid > Foaming/liquid. pH may play a role, as well as the concentration of the surfactants. Another theory is that it takes a lot more time to wash your hands with soap and syndet bars that it takes with liquid detergents. So the mechanical scrubbing of hands is even so more important.