vitalys
Forum Replies Created
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@Graillotion I used to work with this ingredient and I didn’t find either any advantages or positive effects on skin (moisturizing). Indeed, it requires some TEC, otherwise a product will release some Ammonia smell fairly quickly. 1-3% won’t be suffice to achieve any significant response from the skin. You need at least 7-10% of the solution (5% of dry substance) to be efficient. I would use a regular Urea instead, which really works perfectly well starting at 3-5% especially, if you combine it with some other moisturizing constituents.
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@zetein Most likely they won’t be blocked because the molecules of SA will diffuse down a concentration gradient from the vehicle ( high concentration) to SC(lower concentration) while Petrolatum will remain on the surface of skin providing occlusion.
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@Abdullah Yes, it does to some extent. The absorption rate as well as with any other compounds will depend on a type of the skin - thin epidermis or thick epidermis (soles and palms), physiochemical properties of the area at the moment of application, concentration of glycerin, time of exposure, consistency of the barrier lipid bilayers, integrity of the Stratum Corneum, temperature, pathway of absorption - intercellular, transcellular or via skin appendages. Glycerin will penetrate faster in upper layers of Stratum Corneum, and the rate of absorption slows down at the level of Stratum Lucidum and Stratum Granulosum.
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The skin has several barriers. Initially, an emulsion comes in contact with invisible hydro-lipid layer (mantle), which defines pH of the skin surface. This layer contains lipids and components of the natural moisturizing factor including some salts and water. Next, the Stratum Corneum is a highly structured layer of the skin and it has literally “briсk and mortar” configuration where the bricks are corneocytes (contain keratin and NMF) and the mortar that contains lipids. It is important that the lipids are not just a mixture, but they are organized as lipid bilayers and the structure of those bilayers looks very alike as liquid crystal lamellar emulsions. Thus applying the emulsion on the skin equals to mixing of two different emulsions. When you rub your emulsion into the skin, the most of the water content evaporates almost immediately, the rest of the components remain on the surface of the skin while others (mostly lipids) fuse with the lipid bilayers of the Stratum Corneum. Such factors as temperature, skin pH, electrolytes also have a significant impact on the emulsion.
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@Abdullah Yes, the emulsion is going to break down at the moment when it contacts the skin. The ingredients will be absorbed according to their lipophilic/hydrophilic properties. The ingredients, which have the minimal molecular mass will penetrate first. The compounds of higher weight will stay on the skin surface and create the kind of occlusion - petrolatum, for instance.
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This is too complex question to give a short answer and the one of the major aspects of studies in dermatology. There are many factors that define skin penetration. The skin is protective organ, hence it defends the body from nearly any outer substances including those that we consider “good” for us. However, there are two most important factors - the structure of the Stratum Corneum (lipids+water with the components of the Natural Moisturizing Factor), and the molecular weight of a compound that is supposed to be penetrated. There is even the “rule” in Dermatology - the rule of the 500 Daltons. According to the rule, molecules greater than 500 Daltons cannot penetrate the skin barrier. In fact, the molecules greater than 500 Da can penetrate with the aid of enhancers (for instance glycols, solvents, surfactants or Urea). All the penetration enhancer affect the structures of the Stratum Corneum. Basically, the lipophilic ingredients have much better penetration potential than water soluble, the w/o emulsions and lamellar emulsions are most efficient form for the delivery and penetration than o/w emulsions while water based gels, water solutions are the least efficacious due to their nature.
You may find out more if you read the special literature. I recommend to study works by Albert Kligman first, the father of the modern Cosmetology and Dermatology. He also found a doctrine of Corneology and Corneotherapy - the science that researches the Stratum Corneum. I bet this knowledge enormously helps any formulators and cosmetic chemists/pharmaceutical chemists in their work. -
@Melissa This essential oil may contain several types of Azulenes, all of them are volatile compounds, which explains the color change of your product.
You may also try Guaiazulene from Symrise either 100% or water-soluble version - 25%, which is quite stable in terms of color changing. Glass or metal containers are also recommended for the products that contain Azulenes. -
@chemicallydivinelab Do you mix this base with pigments to get the color polish or use it as a clear polish? The excessive % of pigments leads to peeling.
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@ggpetrov
You may find this alternative system interesting to study - HLD system.
HLD | Practical Surfactants Science | Prof Steven Abbott -
@Pharma, I really appreciate your swift response. Yes, the thing is I use the base. That is why I have assumed the possible interaction with Taurine. Yes, I agree, the arginine salts are stable as well as a free base solutions and I like some of them in different formulations. So it turns out now that I need to try some neutralized form of Arginine ( with lactic acid, for instance) to make the mix with Taurine stable in one solution and further in the formulation. This product is going to be used for the very special diabetic foot care (not a treatment) and my customer(a podiatric clinic) would like to explore the benefits of those two amino acids along with other actives in a form of a cream.
Again, thank you for you valuable help, @Pharma It is always a pleasure to read your posts. 🙂 -
@Pharma , Thank you for your explanation. Yes, Taurine is considered as an amino acid. So, they can exist together in a product intact, aren’t they? What is going to happen with zwitterion of Taurine then? Both compounds have different pKa.
I just have made a water solution of these amino acids in equimolar ratio. The solution had remained clear and colorless in the beginning but after two hours it became yellow. What could cause this yellowing? -
Marketing, marketing and marketing once again 😉
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It sounds like another fear mongering marketing wave.
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@PhilGeis Thank you for the links. I wanted to find out what stands behind all those marketing phrases as “Broad spectrum…”, i.e. some tips or tricks if someone works with this stuff, etc.
The initial trials/tests I have made show excellent results in preservation. I have not noticed any issues with it’s solubility at the recommended dosage.@Pharma I appreciate your response.
According to some papers and official assessments O-Cymen-5-ol is not an irritant or allergen up to 0.5%. However, the recommended % is 0.1-0.2%. It is also interesting that one of the formulation we have prepared with this ingredient shows calming and obviously soothing effect on the inflamed skin of our volunteers. The lotion contained no other calming or antiphlogistic components - just the simplest o/w emulsion, preserved with O-Cymen. I assume this effect was due it’s antimicrobial activity.
Yes, the fact that it’s odorless and tasteless is a great plus, especially for some specific preparations. -
@Abdullah
All the preservatives work on the molecular level. Some of them come into direct chemical contact with membrane lipids (for instance alkali) and saponify them whilst another denature the proteins (formaldehyde and formaldehyde releasers), third disrupt enzymatic system of the bacteria or fungi, fourth changes the intracellular pH of the cell, which lead to the cell death. -
As it is mentioned in the literature this acid is comparable to hydroquinone against pigmentation. I would say it has low efficacy and hydroquinone is still a standard.
Please see the file attached -
The most preservatives destroy the cell membrane of the bacterial or fungal cells. However, some of the solutions like hypertonic solutions (NaCl for example) cause the cell death too.
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Hand creams (as well as formulations for foot care) are quite challenging and in fact, they are harder to formulate than the regular products for the skin care. The principal challenge is a fact that you have to deal with two skin types - the skin of the palm is significantly different from the back of the hand both structurally, physiologically and histologically. The skin permeation of those two types is also different. Thus you have to balance the ingredients to match both skin types.
According to my experience, if you want to create the superb hand cream the type of the emulsifying system is crucial. The best one to choose is so called lamellar emulsions with two types of emulsifiers - the mixture of low HLB and high HLB emulsifiers. I have noticed that regretfully, major commercially available branded mixtures don’t work sufficiently well for hands and feet. Old good GMS (not a standard grade - you need 90-99% of monoesters) coupled with tiniest amount of SLS or SLES (I hope your marketing department won’t kill you for this inclusion 😉 ) makes the luxurious cream and nice stable structure of the emulsion. If SLS is a “no-no” ingredient the experiments with tricky Sodium Stearoyl Glutamate or something like this would be fine too.
Another approach is using modern polyglycerol surfactants. They can create very valuable w/o light emulsions with high water content and they can be considered as “protective” and highly moisturizing for the hand creams too.
Re: Alcohols.
Mixtures of cetyl/stearyl alcohols with behenyl alcohol would be excellent as @Pharma mentioned. Some hydrogenated oils (i.e. waxes) too.
Octyl Palmitate, Isopropyl Myristate/Palmitate, Squalane are the esters to choose from too for emolliency and skin feel.
I also like Stearic acid in this type of formulation despite it looks outdated. When it is coupled with 90-99% GMS (monoglycerides) it works as waxes and provides the velvet feel. -
@SlingerD. What CBD oil is intended to do in your formulation?
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@SlingerD These types of formulation is quite difficult to create to keep them safe and pleasurable. pH of the final product and osmolality along with irritating potential of the ingredients are the key factors.
I am afraid that Aloe is an appropriate ingredient in this type of formulations due to its high irritating potential for the mucous membranes and the tender skin. It is getting even more irritated when coupling with surfactants, especially those that are regularly used as solubilizers.
I assume that the tacky effect comes from Glycerin, Aloe, Gum, PEG 40 HCO and Polysorbate.
Small amount of cationics could be added carefully, but they can be also highly irritated. -
hasanarsan, Thank you for your input, but sugar renders yellow tint to the soap at high temperatures.
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I also suppose that Soybean Peroxidase and Superoxide Dismutase have been added to the mix as antioxidants in order to support Arborcide activity along with Citral which has good antibacterial properties as well, despite they put it as a part of fragrance.
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Thank you so much, Johnb for your expert input. I have ommited BHT and advised to use a trace % of Sodium Metabisulfite and it solved the problem completely. The result is waterlike colorless soap.
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@ gfeldman , This problem could be solved successfully with:
- AAK’s Lipex Shealight
- AAK’s Lipex Sheaclear
- Phoenix’s Phoenoxol BD-10P
There are some other emolients you may find useful in Phoenix’s product list as well -
@BartJ , They have got their own ingredients. The technical data are identical to mine ones. However, they get the results like this.