jeremien
Forum Replies Created
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does anyone know where to buy Sodium Levulinate in water solution (without other preservative)?
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HLB is an acceptable initial approach to select
surfactant. Nevertheless it’s quite simple system, and does not give indication
on the structure of the surfactant. Lecithin and steareth-2 are very different
molecules, so I agree with Belassi you have to try -
you cannot make a stable emulsion with cetyl alcohol, but it acts as co-surfactant… It will be present at the interface oil/water of the emulsion
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I understand that dealing with ethoxylated alcohols or PEG, you will have the same concern of traces of ethylene oxyde and 1,4 dioxane
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How do you base you decision to indicate 6 months shelf life? Only from microbiological data?
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You can have a look to emulsifiers used in the food industry,e.g. lecithins, sucrose esters …
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I would add
4. HRIPT (long test: 6 weeks, and need many volunteer e.g. 50)
5. Open test (duration max 5 days)Both allow you to add the claim ” tested under dermatological control”
HRIPT allows also the claim “Hypoallergenic product” and “minimizes allergy risks” -
In my oppinion, polymer, by there size will not help for skin penetration. Even if if the lower viscosity polymer have lower Mw, it is still too large to penetrate the SC
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@Microformulation in my case it was a face cream. I believe that shampoo/conditioners contain high amount of ionic species (salt, surfactant,
polymer..) that already limit the microorganism growth.
Why do you use the Dermofeel Pa-3 that contains ethanol and not the Dermofeel PA without ethanol? -
@Dr Catherine Pratt i try Leucidal SF complete at 4% without any other preservative, and Challenge failed
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Squalane is chemically more stable than squalene
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well, my question was to list the acids that can be used in cosmetic to decrese the pH below 5.
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@ChemicalPyros In the case of Phase inversion with TºC, with clasical cosmetics ethoxylated surfactant with HLB between 12-18, you have good chance to find a ME phase or Lamellar crystalline phase (it may be part of multiphase system) in between 20ºC and 80ºC. In the case of inversion under dilution, studying phase behaviour will also show that many system present ME or Lalpha phase in some regions. C.Solans is one of the reference in this field with Salager and Kunieda. I had the honor and the chance to work with them.
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I would add that sometime to produce O/W eulsion, it is better to add the water to the oil to carry out a phase inversion, and to obtain smaller droplet size and lower polydispersity.
In the case of mechanical stirring, at a certain point, adding more energy does not reduce the droplet size. You have to remember that by mechanical techniques more than 99% of the energy input is lost in form of heat because of viscous dissipation. At the end, less than 1% of the energy is used to emulsify the system.
To obtain small droplet size and low polidispersity the best choice is to select a surfactant system that allows to decrease at the minimum the interfacial tension. -
there is a lot of legends on peptide stability that may be explain by the high price, but at the end, in general they are quite stable molecules.
Better to add them at the end of the preparation as most of them are very surface actives. -
@Doreen what i cannot understand, is that how the European comision, FDA or private label such as COSMOS could allow this preservative if it seems so obvious that many people notice redness with this product.
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@Doreen How do you know that your redness come from potassium sorbate?
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The problem with DoE apply to formulation, is that
response are not predictable, since the phase behavior is not lineal, and show
catastrophic change with very narrow change in composition. Phase diagram is
the only approach that can give you a full picture of a cosmetic system… unfortunately
it is very time consuming. -
I mean: if carbomer is dispersed in the oil phase, there is a kinetic of migration/hydration of the carbomer from the oil droplets to the water.
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What is the advantage to add the carbomer in the oil phase? emulsion stabilization? better dispersion of the powder? How fast is the migration of the carbomer from the oil phase to the water phase?
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in the new ISO 16128, i guess thta you have to specify if you give the organic content with or without formulation water. In all case, formulation water cannot be considered as organic.
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@Perry
good question
you try different combination of preservatives and after checking that it doesn’t affect the physchem properties of the product, you try to pass the Challenge … i guess that all the comsetic industry have the same problem today… time and money consuming, and as far as i know, there is not a unique solution that work for all formulations. -
@Max I thought that retinal was protected by a patent. The problem with Retinol Acetate or palmitate, is the efectivness, much lower than retinol
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@Microformulation people who encapsulate or stabilize it must find the pure retinol somwhere isn’t it?
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even with this opinion, today it is very difficult to sell cosmetics with phenoxyethanol in Europe, especially in country like France