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Would this toothpaste require a preservative?
I don’t know how to test the water activity of this toothpaste. Sure, I found the formula on-line, but it’s not like I can do the actual test at home. SO….
Would a toothpaste made with this range of ingredients, need a preservative?
I usually use 0.26% sodium benzoate, but since this toothpaste ends up with a pH of around 7, I figure it is INeffective in its work.Glycerin 48%
Water 21.6%
Calcium Carbonate 20% (of appropriate particle size)
Silica (hydrated) 6.4%
Flavor 1%
Cocamidopropylbetaine 1%
Polysorbate 80 1%
Xanthan gum LESS than 1%THANKS VERY MUCH FOR YOUR TIME FOR HELPING ME WITH THIS!
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8 Replies
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@Margaret
you still need to add a preservative because you have water present.
water is a breeding ground for bacteria. -
@Margaret How are you measuring pH? I ask, because with that amount to Calcium carbonate, I’d expect the product to be more alkaline. Also, 48% of Glycerine is very high; if you add also the high level of Calcium carbonate, I’d suspect the water activity is low enogh to prevent microbial growth, but you need to know for sure what’s the water activity.
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You should never guess to add or not a preservative or to guess the efficacy. You have to test it! Indeed you have a lot of glycerin, you can test your formulation as is, but you should as well consider adding a proper preservative.
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I use 0.26% sodium benzoate (mentioned above), but I left it out of the formula. Sorry for the confusion ????. I was thinking that since sodium benzoate is not effective at less than pH 5.5 why is it used by toothpaste manufacturers?
I only have pH strips, they are from Germany (Macherey Nagel brand) not the cheap ones from China. I canNOT afford a good pH meter made in the U.S. I do not want to buy one made in China. I used these exact same strips to test the pH of Crest toothpaste, and it too was 5.5.
I used to use sorbitol AND glycerin, about 50% total of these glycols, but sorbitol is more expensive and I read that glycerin is better at decreasing water activity than sorbitol is.
The formula I am using is based on ingredient ranges of toothpastes that I found on Happi or through various pharmaceutical articles on-line. I would not copy a formula posted on a blog or You Tube or something like that. My formula is also similar to those given on a Lubrizol website from several years ago.
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I re-tested the Crest toothpaste, and it’s pH is now 6, not 5.5, which it was when I first opened the tube, maybe a year or more, ago. Perhaps pH drift has occurred?
MY toothpaste, as written above, is pH 8, not 7. The pH discrepancy might have been due to the mouthwash that I used instead of straight water, at 21.6%. I assumed using a fluoridated mouthwash instead of water would yield a small amount of anti-cavity protection. I think the mouthwash was either Colgate or Crest brand.
Our tap water is pH 7 according to city reports. It is extremely “soft” regarding mineral content.
The pH testing was done with pH strips. I know they are not nearly as good as a pH meter.
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Your formulating with another company’s product, apparently a drug product.
Don’t think you listed those ingredients.
Are you planning to sell this? -
Margaret said:I use 0.26% sodium benzoate (mentioned above), but I left it out of the formula. Sorry for the confusion ????. I was thinking that since sodium benzoate is not effective at less than pH 5.5 why is it used by toothpaste manufacturers?
…Sodium benzoate is most likely not active in your product.Calcium carbonate is poorly soluble in water and very poorly soluble in polyols. That’s why it doesn’t increase pH much. Diluting it with distilled water before measuring with a paper strip would be wise, these strips do not work properly with suspensions of pH active compounds (however, dilution will likely increase pH). Calcium carbonate isn’t reducing water activity to any useful degree. Even with a 5:2 mix of glycerol to water (roughly 70% or aw 0.66), your water activity is still in the range of ‘some microbes can grow in there’. Sure, it’s in a range where no pathogenic microbes can grow and only extremophiles dwell (not all of these like alkaline conditions)… If you want to be on the really safe side, aim for 80-85% polyol content, add salt (several of the possible survivours don’t do well in brine) or use a pH independent preservative (maybe, though you’ll have to test, essential oils and the like could be enough to give it the last kick).I would wager that you can easily switch back to a blend of glycerol plus sorbitol (xylitol would be even better in a toothpaste), the minor increase in water activity will not reduce self-preservation to a noticeable level.For personal use = short shelf life, your formulation looks safe enough to me. -
REGARDING USING MOUTHWASH IN THIS. NO, this is not being sold. I merely used the mouthwash to dissolve the xantham gum instead of water (I normally use water) since the mouthwash had fluoride in it. Our water here does NOT have fluoride in it, unfortunately.
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