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Silver citrate and Silver Dihydrogen citrate as a preservative
Recently I did some research on baby wipes and came across Silver Citrate and also Silver Dihydrogen citrate as a preservative. It seems to be used with sodium citrate or Citric acid to regulate pH? Has anyone used these preservatives in their formulations for lotions or creams? Have you got any feed back at the effectiveness. I am particularly interested in Silver citrate as it does not use nanotechnology. Would this be a good way of preserving pasteurised rose water further?
thanks in advance
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18 Replies
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Think you would do better with a conventional preservative such as Geoguard Ultra or Benzoic acid/Benzy alcohol.
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This preservative is sold under the trade name Tinosan SDC. It is my understanding that the products need to be protected from light.
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This company had contamination (?) problems with silver citrate. Watch this discussion.
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Thanks for the info heraklit, There are also other companies that use silver citrate and have not had problems, however I can’t ignore the honest company experience. Maybe their silver citrate was exposed to light??
Does that mean Silver dihydrogen citrate is more effective?
Thanks ozgirl, the info about light sensitivity is very helpful
DrBob Thank you, for suggestions Benzoic acid/Benzy alcohol. Did you recommend that for further preserving pasteurised rosewater?.
I can’t help but think maybe silver citrate could be mixed with another preservative/s to improve effectivity? Would love to know.Not that I want to make baby wipes however silver citrate looked attractive as a preservative for a lotion.
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silver citrate has antibacterial properties but remember, protection against fungi is also crucial.
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caprylyl glycol, sorbic acid/potassium sorbate, levulinic acid, anisic acid, could any of these be added to fortify silver citrate. I’m not a chemist but love pushing myself to understand. I’m fascinated.
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I don’t have a great deal of faith in these silver citrate preservative systems. A few years ago a whole line originally formulated by a Contract Manufacturer used this in all the client’s products. The products failed challenge testing and failed stability as the Silver discolored into the second 28-day cycle. They had me fix the entire line. It was at the beginning of December so it was a Merry Christmas! If you are trying to meet a natural standard or avoid certain products due to market bias, there is a huge number of candidates I would consider before this product.
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thanks Mark Fuller, when you say
“If you are trying to meet a natural standard or avoid certain products due to market bias, there is a huge number of candidates I would consider before this product. ”What are the candidates that you would consider?
“The products failed challenge testing and failed stability as the Silver discolored into the second 28-day cycle. They had me fix the entire line.”
When the products failed challenge testing in what way did they fail? Mould? type of bacteria…? Could you elaborate? How did they discolor did they go blue? What was the nature of the products you were making lotions? creams?
How did you fix the entire line?Eventually I’d like to make a low viscosity lotion that carries the alcohol based herbal actives.
Personally after a few years of researching cosmetic ingredients and reading the ingredients lists of countless items Silver citrate showed some interest to me as a preservative because it is likely to be not absorbed into the users body, not have any ill effect on contact and not likely to cause environmental toxicity.
when I did the research on baby wipes, some wipes claimed to be compostable I wondered what the silver citrate does to the beneficial bacteria in soils.
I did see a claim made about nanoparticle silver being of danger to fish and that nano silver has been found in animal organs. I don’t know how true this is.
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What are the candidates that you would consider? There are far too many to name in this forum. Preservation is a topic that takes up a large part of any Formulators continued learning.
I will say that first, you need a definition of what is “natural.” Leaving this term undefined is fine in marketing, but it serves no purpose and in fact is a hindrance to the R&D process. Let me state my definition, albeit it is just my attempt to facilitate the R&D Process. “Plant-based and naturally occurring minerals minimally processed.” Before we belabor what minimally processed is, I will direct you to the COSMOS standard which defines the allowed processes. To simplify, you can say that they are processes that are observed in nature. “Why process them at all?” you may ask. Well, crushed leaves and nuts do not work well and as such most materials must be processed, purified or altered in order to effectively utilize them in skincare.
Right now, in my Market Organic acids are common but they have pH restrictions and can also discolor. Combinations of Phenoxyethanol and a glycol combined with a chelant are also popular and endorsed under many standards.
Can I cover them all? NO. You can not expect to learn reams of information in a forum such as this. You must set a high bar for your sources of information and study extensively. Essentially, if you found it in a google search, you should be suspicious. Blogs are not credentialed. Blogs mean you have a pc and an internet connection, often not much else. Until you raise the bar on your sources and study, you are not ready.
When the products failed challenge testing in what way did they fail? They failed a challenge test. Again, a topic to study on your own. They discolored by darkening, not blue. We are not dealing with colloidal silvers here. They were all topical emulsion products. I will be purposefully vague as my NDA’s set barriers in these areas.
Silver citrate showed some interest to me as a preservative because it is likely to be not absorbed into the user’s body, not have any ill effect on contact and not likely to cause environmental toxicity.
Nearly every approved Cosmetic preservative fits these parameters. Again, vet your references and see. Many of the topics you reference are based upon chemophobia and lack scientific foundations. That being said, when following a natural standard and in Formulating overall, you must accept that some products are avoided not so much by Science but due to Marketing bias. An intelligent line knows that your time to initially promote your product to a customer is finite and you do not need to waste it by dispelling their marketing based beliefs. This was different way back in the late 90’s and early 2000’s when I started seeing an increased demand for “natural”, BUT the chemical distributors have really stepped up.
Lastly, a bit of tongue in cheek humor; I’m not a chemist but love pushing myself to understand.
I am not a Veterinarian but I love pushing myself to understand. Boy are my neighbors pissed at me about their cat!
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Thanks so much for your opinions, time you’ve taken to share your experience and knowledge Mark. Yes in researching the internet I went round and round in circles trying to find a preservative that does no harm. There is a lot of talking heads with chemophobia as you put it and I’m trying hard to not be one of them. I’m trying to sift through the BS. However marketing bias is a reality and as you put it in an earlier post (and I love the quote) “The client is not always right, but the client is always the client.”
For the last 20 years working as a naturopath in a pharmacy setting I have been mixing into a base cream natural actives, for my clients with great success in results. One day I decided I would rather go into manufacturing my own products. So began the research into cosmetic science. The more I researched the more I realised how much I don’t know. Hence I am here to be aware of what I need to be aware of until my circumstances are such that I can bring a product to market.
Sooner or later I will need a cosmetic chemist, right now I’m enjoying the learning and the challenges that this brings.
And Mark I am somewhat interested in Phenoxyethanol based preservatives as that is what the base cream that I was using is preserved with however the following link states that there are concerns with carcinogenic activity which leaves me uncomfortable.
http://microchemlab.com/five_most_common_types_of_preservatives_used_in_cosmetics .
Staying on Silver Citrate, could I use piroctone olamine an anti fungal with silver citrate? Would these react with each other and render each other useless or could they potentiate each others actions? Once again I’m not a chemist but love to understand.
Could anyone direct me where i can find more info on co-preservatives to use with silver citrate or share more of your experiences.
Thanks in advance
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There are a number of “natural” preservatives that are just plain junk. Don’t forget that preservation is not simply adding a preservative into a formula, but using hurdle technology … pH (low), glycols to reduce water activity, etc.
If you want to use Silver Citrate for label purposes … no problem. But, couple it with other microbial hurdle ingredients and a reputable natural preservative of which there are several options. I am particularly fond of the natural preservatives from Lincoln Fine Ingredients.
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thank you I will look up Lincoln Fine ingredients for a co preservative.
How would you do a hurdle technology on baby wipes?
recently a friend bought a baby wipe company at an incredibly good price and asked me to do market research for her. Her company ethos is organic and natural. The brand she purchased utilises Potassium sorbate, sodium benzoate as preservatives. Unfortunately the bloggers have a lot of sway in how & what parents buy. The silver citrate as an ingredient doesn’t get a bad wrap but sodium benzoate does.
I then got excited about the silver citrate and thought could it be a preservative for the Rose water I get from an Iranian shop. The rose water smells divine with no preservative but the process of pasteurisation. Cost is low as opposed to rosewater sold for making cosmetics with nowhere near the great scent of the Iranian rose water.
From memory, I think it was in one of your posts Mark Broussard that you were saying Rose water doesn’t need preserving because its self preserving due to its natural phenethyl alcohol content. What to do with such a lovely smelling hydrosol? Unsure of any possible bacterial load …………….. do I add silver citrate and more phenethyl alcohol to preserve it. Or treat is as a juice and add Potassium sorbate, sodium benzoate, citric acid as preservatives? AND THEN FORMULATE??????? Upon opening adding preservatives months after manufacture of the rosewater that is pasturised, is that a good idea?? or should it be done at the time of manufacture? And when one is using such a hydrosol and makes a lotion with it and then adds the appropriate preservative for the lotion is that likely to be adequately preserved? Thanks for sharing experience and knowledge.
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You can use Silver Citrate combined with Linatural Ultra-3 (from Lincoln) for the Rose Water (or most any of your products for that matter). The components are Phenethyl Alcohol (from Rose and it has a Rose scent), Pentylene Glycol and Propanediol and it has a broad pH range, but always best to use Citric Acid to get your pH below 6.0.
Yes, you can add a preservative to the Rose Water if it is not preserved, no problems.
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Wow the Linatural Ultra-3 looks great thank you so much Mark Broussard. I hope I can get a supply of it locally. I’m grateful to all the commentators thank you. Last few questions,
I do have about 15ml sample of of phenethyl alcohol it has a powerfully rosy aroma despite it being in a closed bottle. What’s the best usage rate as a co preservative to give a nice rosy scent to a formulation without overpowering it, and over time does the rose scent evaporate if the product is kept in a jar with constant opening and closing.
Is there a specific pH it works best at or a certain temperature I shouldn’t go beyond or any other substance I shouldn’t use with it lest it may get inactivated and so forth? Yes is there any information specific to phenethyl alcohol that I should know about from your experience? Thank you for sharing your invaluable experiences.
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Neat Phenethyl Alcohol is quite expensive and it really isn’t that soluble in water. You can try incorporating it at 0.6%, but you’ll probably need to use a solubilizer.
If you dilute it in propanediol or pentylene glycol, that would also help.
The pH range is 3.0 to 8.0 and it is not heat sensitive.
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thank you for your help Mark Broussard and everyone who contributed to the discussion.
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Hello Everyone
I did make products with Silver Citrate as an antibacterial ingredient but keep in mind that is important for it to work properly to abide with the following observations that I had after many failures in challenge testing
1. A broad spectrum preservation with a booster (ethyl hexyl glycerine/caprylyl glycol) is needed. Do not rely on Silver Citrate
2. pH should be between 3-5 for it to optimally work
3. Darkening is not influencing its efficacy. Use always packaging that does not allow light to penetrate, othewise use Benzophenone-4 or covasorb ds as Silver is sensitive to UVA radiation
4. EDTA, Cocamidopropyl Hydroxysultaine, SLES, SLS, Sodium Lauroyl Sulfosuccinate or/and sarcosinates cause Ag to form complexes and finaly to sedimentate in the bottom. This deactivates the antibacterial effect of the product.
5. It is compatible with cocamidapropyl betaine at 0.3% or less, PEGs as solubilizers and fragrances/essential oils.
6. Better used in very simple systems as AgCi is prone to pH changes or long term oxidations/reactions. Vitamin E 0,1%+ Peg40 hydrogenated castor oil at 0.5% increases slightly its self life. Difficult to be used in creams as it darkens the final product even with the use of UVA filter. -
There are so many better preservatives that are as well received in the markets, more effective, more stable, better spectrum and easier to use. Except to meet a Marketing demand with blinders on, where is the utility?
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