MakingSkincare
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1. Have a check of this webpage to check if your preservative has the potential to be broad spectrum -http://makingskincare.com/preservatives/ NB: from the choices available to homecrafters: Phenonip, germaben and liquid germall plus tend to be more effective.
2. Minimise sources of energy for microbial growth (aka “bug food”) - eg fruit, botanicals, tea, lecithin, mineral water, milk of any kind, honey, hydrosols, floral waters, aloe vera, extracts, protein, clay, powders, starches etc - reduce these to a tiny % (eg 0.1%). This is crucial, especially if you’re using one of the more “natural” type preservatives.
3. Add glycerin and other polyols
4. Add 0.2% disodium EDTA into the heated water phase
5. Switch to packaging which the customer can’t contaminate easily - jars are the worst for contamination.
6. Reduce the pH to between 4 and 5 if possible.
7. Sanitise your equipment with 70% IPA
8. Use distilled, deionised or purified water, not tap/faucet or mineral water
9. Heat and hold your water phase at 75c/167f for 20 minutes - this will kill some of the non-endospore forming bacteria. (If your preservative can withstand heat put it in the heated water phase rather than the heated oil phase. This improves preservative contact with the water phase so that it is not partitioned in the water-oil interface).
10. If possible micro test all of your raw materials.
11. Use good GMP - http://www.mariegale.com/good-manufacturing-practices/gmp-basics.html
Don’t rely on sight, smell - one can put 100,000 bacteria into a milliliter of water and the water will appear to the naked eye to be crystal clear and won’t smell. Most cosmetics tested have counts ranging into the tens of thousands or millions of cells per milliliter have subtle or no aesthetic differences from sterile samples. The only way to know if your preservative system is working is to get it tested. -
If there are components that require melting into a particular phase, they won’t actually be homogeneously mixed into their preferred phase before an emulsion starts to form –particularly an issue when using a solid emulsifier. Obviously this will impact on how the micelle structure sets up and thus effect the finished product. So the 2 pot method will likely produce smaller particles which will make the product adsorb quicker. Homgenising can of course adjust both size and eveness if your emulsion can take extra.You try adding all the oil phase and the liquid to one vessel and heat through in one then emulsify. Some conditioners are made like this, but they usually have a quite simple oil phase.Also with one pot processing, using an emulsifier that is compatible with both phases, and is liquid at room temperature works can work well.
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To add to Mark’s comment - http://ec.europa.eu/health/scientific_committees/consumer_safety/opinions/index_en.htm
and some info on preservatives - http://makingskincare.com/preservatives/
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Yes, with salicylic acid, you’ll get a lot of discoloration if there’s divalent cations like Iron.
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Danielyau - see this post - http://makingskincare.com/preservatives/
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Re preservatives - http://makingskincare.com/preservatives/
For the rest of your question see swiftcraftymonkey’s blog.
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It’s hard to troubleshoot without the full formula in %
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Can you give the full formula in %? It’s hard to troubleshoot without this.
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You might find this helpful - http://swiftcraftymonkey.blogspot.co.uk/2010/04/which-surfactants-should-you-buy.html And she also has tutorials for shampoo.
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To add to the above, some more solubilisers:-
- isopentadiol,
- betaine (this isn’t cocamidopropyl betaine)
and buffer (using citric acid and sodium citrate) to a pH of 3-4.
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vjay, try milliachemists suggestions or you might find it easier to use a non-ionic modern emulsification system
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Yes as milliachemist says sodium lactate is an electrolyte and unless you have the carbopol ultrez 30+ version, I would use glycerin as your humectant instead.
You could use a fatty acid/alcohol to thicken eg cetyl alcohol and that will also help stabilise your lotion. Ewax NF should work fine with C12-15 alkyl benzoate. -
Zoe, no-one can tell you whether a preservative will be effective or not. You will need a lab test for that.What I can say is that the preservatives you mention (Phenoxyethanol and Ethylhexyglycerin and Dermosoft 1388 eco/GMCY), being the more “natural” type preservatives, will prove a real challenge to preserve the clay/bamboo. Even if the clay has been irridiated, clays are problematic because they adsorb spores onto them and the large surface area makes it difficult for your preservative to cover everything. Clays also tend to deactivate formaldehyde donor preservatives.Do bear in mind that there’s a lot more to preservation than just adding a preservative eg reducing water activity, using packaging which minimises contamination in use, microbiological testing of raw ingredients and process water, etc and adding 0.1% disodium EDTA (heated water phase) and glycols will help. Another major factor is the amount of “bug food” in the formula - this often gives overlooked. I see many people putting tea, goat’s milk, honey, hydrosols, floral waters, aloe vera, extracts, protein, powders, starches etc in their formulas which will really challenge the preservative system - reduce these to a tiny % (eg 0.1%).More info including reviews of 27 preservatives - http://makingskincare.com/preservatives/
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The stability of an emulsion is controlled by:-- interfacial surface forces,- size of the disperse phase droplets,- viscous properties of the continuous phase and- density difference between the two phases.(Stokes law).However some would argue that Stokes law doesn’t apply to any non Newtonian fluid like ketchup or lotion and that standard Navier-Stokes equations should be used instead (parameterized and coupled then constants can be backed out using numerical quadrature). Interesting discussion on this here - https://www.facebook.com/groups/makingskincare/permalink/468977136561449/
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It might be an idea to have, if it’s possible, a “pinned post/thread” at the top of the forum (just like the formulating services is pinned to the top) with basic useful info for the newbie formulator eg links to places to find formulas, where to purchase ingredients in small quantities, online tutorials (eg swiftcraftymonkey’s), link to Perry’s course, link to preservative info (http://makingskincare.com/preservatives/), etc.
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Ditto what Bob says.Assuming formula compatibility, Germall II powder (.2%) coupled with these powders: methylparaben (.2%) and propyl or ethylparaben (.1%).Using liquid preservatives in powders is a challenge to get homogeneity in the batch. However, if you are confident that you can achieve complete homogeneity, you might try: 0.6% Germaben II with 0.3% Sodium Benzoate. Another possibility is a system of 0.5% Phenoxyethanol, 0.3% Sodium Benzoate, and 0.3% Potassium Sorbate.Whatever preservative blend you decide to try you will need to get this tested.
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Try keeping the pH below 6 and add a sulfite based antioxidant.
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If you mean what milliachemist mentions then this post will tell you how to determine active surface matter - http://itsallinmyhands.com/2013/04/23/on-surfactants-and-formulation-face-wash-shampoo-and-shower-gels/
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Thanks Itsallinmyhands. Welcome to the forum.
I have used powdered DLSS in my shampoo/body washes without diluting it first so I’m not sure I understand why he wants to do this. -
cosmo_girl - this article explains it well - http://www.cosmeticsandtoiletries.com/research/chemistry/17390254.html
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A shampoo for normal hair, might only have a total active concentration of 13%. This 13% is comprised of a blend of surfactants.
For example Ammonium cocoyl isethionate (30% active) used at 15%, Decyl glucoside (53% active) at 8% and 15% Cocamidopropyl betaine (30% active) makes a total active concentration of 13.24%. The rest of the formula will consist of water, viscosity modifier, conditioning agent, pH adjuster, preservative, fragrance etc.You should use a blend of surfactants rather than just one.The formula I linked to above, uses DLSS at 5% so if you were to experiment with it at 5%, this means it will be 1.6% active concentration. If you’re looking for your shampoo to total 13% active concentration then you’ll need to add other surfactants.Do have a read of this - http://swiftcraftymonkey.blogspot.co.uk/2009/03/surfactants-short-guide-to-things.html -
See the sample formula posted above for how to work with DLSS.
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Sample formula - http://www.clr-berlin.com/files/243_03_0401_herbal_body_cleansing_foam__sles-free.pdf32% active doesn’t mean to add 32g to 100g water.Here’s more info on what 32% active means - http://itsallinmyhands.com/2013/04/23/on-surfactants-and-formulation-face-wash-shampoo-and-shower-gels/
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Rencelji - some info on DLSS and how to use it - http://swiftcraftymonkey.blogspot.co.uk/2010/04/surfactants-sulfosuccinates.html