Any suggestion or comment for that cream

FekherFekher Member, Professional Chemist
edited September 14 in General
 I made base cream with
Petrolatum 17%
Ctearyl alcohol 5%
Stearic acid 2%
peg 40  3,5%
Dimethicone 350 2%
Neutralised carbomer
Water
Perfume
Presevative

  So any input for improvement or comment will be welcomed 😊

@Perry @Abdullah @ketchito @Paprik @ngarayeva001 @chemicalmatt @DRBOB@VERDIENT.BIZ

Comments

  • So you say you have made it, right? 
    The questions should come from you. Do you like it? Or do you feel like it should be more hydrating or you're having stability issues? Or something else? 

    Just looking at your formula, you are lacking humectant. Quite high lipid input. Have you freeze/thaw it [stability test]? 

    Try the cream and let us know if you would like to improve something or help with specific issue. :)
  • What Paprik said+ what is peg 40 doing and what is the emulsifier?
  • @Fekher You also need to add some base (sodium hydroxide for instance) to neutralize the Stearic acid, so it can work as an emulsifier.
  • ketchito said:
    @Fekher You also need to add some base (sodium hydroxide for instance) to neutralize the Stearic acid, so it can work as an emulsifier.
    I have never understood this.  :/ So Stearic acid needs some base to be able to be emulsifier (saponification I reckon). But wouldn't it need higher pH to be able to maintain its properties? Meaning, if you would take the pH back down, it should "separate", shouldn't it? 
    Could you please explain it to me good man? :)
  • PharmaPharma Member, Pharmacist
    Paprik said:
    I have never understood this.  :/ So Stearic acid needs some base to be able to be emulsifier (saponification I reckon). But wouldn't it need higher pH to be able to maintain its properties? Meaning, if you would take the pH back down, it should "separate", shouldn't it? 
    Could you please explain it to me good man? :)
    LoL! Spot on!
    What can happen is: Convert some stearic acid into sodium stearate aka soap which allows you to emulsify your product quite easily. Drop pH and convert most soap back to stearic acid. Stearic acid (and other stuff) settles and thereby hardens the oil phase. Voilà, you have created something like an unstable stable non-emulsion-but-suspension emulsion :) . The remaining small amount of negatively charged soap on the interphase might be just enough to keep the oil droplets (I should rather say 'fat' cause they're solid) electrostatically rejecting each other.
    It's pretty much how traditional cold cream has been made (though that one was w/o).
  • Paprik said:
    ketchito said:
    @Fekher You also need to add some base (sodium hydroxide for instance) to neutralize the Stearic acid, so it can work as an emulsifier.
    I have never understood this.  :/ So Stearic acid needs some base to be able to be emulsifier (saponification I reckon). But wouldn't it need higher pH to be able to maintain its properties? Meaning, if you would take the pH back down, it should "separate", shouldn't it? 
    Could you please explain it to me good man? :)
    Hehehe....Yes I have met others that did your course work, and they did not understand it as well.  In fact, they got violent when I tried to explain it....and I had to leave the group, as no one needs that in their life.  ;)
  • I could not find it (of course).  But someone has posted a link...to the history of cold creams... which discusses how in the presence of a strong alkali, stearic acid can be converted to a stearate soap (simple emulsifier).  Where the confusion my lay.... is stearic acid WILL thicken without the alkali....however...thicken and emulsify...are not the same. :) 
  • FekherFekher Member, Professional Chemist
    edited September 15
    @Paprik for sure I made it, actually almost comments are positive about it however I find it greasy then even with dimethicone it still litel bit soaping, the texture is amazing good viscosity and good spreadability. I tried dimethicone for soaping effect and IPM for greasy effect but for me still not satisfied and about humectant just I forgot I already used MPG.
    @Abdullah about emulsifier there is no precise ingredient however it is combination (Ctearyl alcohol +Stearic acid +peg40) can do the job of emulsifier
    @Paprik actually Stearic acid is a texture agent not to transform it to emulsifier @ketchito if  you want it will be  TEA with Stearic acid better but as I said Stearic acid is in my formulation just for giving texture. 
  • Use dimethicone 5cst for soaping.
  • Pharma said:
    Paprik said:
    I have never understood this.  :/ So Stearic acid needs some base to be able to be emulsifier (saponification I reckon). But wouldn't it need higher pH to be able to maintain its properties? Meaning, if you would take the pH back down, it should "separate", shouldn't it? 
    Could you please explain it to me good man? :)
    LoL! Spot on!
    What can happen is: Convert some stearic acid into sodium stearate aka soap which allows you to emulsify your product quite easily. Drop pH and convert most soap back to stearic acid. Stearic acid (and other stuff) settles and thereby hardens the oil phase. Voilà, you have created something like an unstable stable non-emulsion-but-suspension emulsion :) . The remaining small amount of negatively charged soap on the interphase might be just enough to keep the oil droplets (I should rather say 'fat' cause they're solid) electrostatically rejecting each other.
    It's pretty much how traditional cold cream has been made (though that one was w/o).
    @Pharma, I couldn't have explained it better if I tried 😅. Another way I see it is that most of the stearic acid resides in the oil phase of the emulsion, being able to interact only through hydrogen bonds with the polar head of the emulsifier, but only if you have one. Now, when neutralized, you have a stearate, whose anionic part moves the molecule closer to the emulsion interfase, strenghten the electric layer and making the lipid part of the molecule align in a way that forms a more ordered and stable structure.
  • FekherFekher Member, Professional Chemist
    @Abdullah I have in hand dimethicone 350 isn't good for soaping? 
  • GraillotionGraillotion Member
    edited September 16
    Fekher said:
    @Abdullah I have in hand dimethicone 350 isn't good for soaping? 
    It works just fine....in fact the industry standard for soaping.  But all will work, just depends on what you want in haptics...as it will slightly alter that.  You can even use D5 for said issue.
  • @pharma Wow, ... :D thanks mate! You explained it perfectly, plus,  confused me a bit more :D nah, kidding .. it does makes sense. 
    Soooo, when would you incorporate the base? I don't think the saponification happens just when you emulsifying, right? It does take a while. @ketchito thank you tooo! 
  • Fekher said:
    @Abdullah I have in hand dimethicone 350 isn't good for soaping? 
    It is better than ingredients other than dimethicone but not even close to 5cst dimethicone.


  • FekherFekher Member, Professional Chemist
    Thanks a lot @Abdullah ;
  • I have a couple of comments on overall aesthetics of the product not stability: 1) you might want to consider dropping  petrolatum down to 5-7% and replacing the rest with mineral oil (so much petrolatum isn’t often necessary) 2) if you have an nonionic o/w emulsifier try that instead of relying of TEA stearate/sodium stearate (you can bring ph down without consequences for stability this way) 3) ditch stearic acid completely, it’s draggy and causes a lot of soaping.
  • Sorry is that PEG-40 solvent or PEG-40 Stearate emulsifier?
  • @Paprik old fashioned cold creams are made like this. You solely rely on immediate saponification reaction between stearic acid and a base where either  TEA stearate or Sodium Stearate is formed. Your base goes to the water phase with other ingredients. You don’t put TEA stearate in your beakers, it’s being created as you mix water and oil phases. This approach is still used in some products like mascaras (even by high end brands) although majority of commercial products rely on ready non ionic emulsifiers (the 165, peg-40 stearate, ceteareth-20 etc).  Since it’s not an actual soap you don’t need to wait for several weeks for reaction to happen. Also the temperature at the moment of emulsification is high (stearic acid should be melted) which make it slightly more similar to a hot process soap. High temperature speeds up the reaction and hot process soaps can be used soon after they are made (cold process soaps are cured for weeks to let reaction happen).
  • FekherFekher Member, Professional Chemist
    @ngarayeva001 nice return for you 😊, actually i agree with you for points 1 and 3 about emulsifier the combination between (stearic acid, cetearyl alcohol, peg40(solubilizer)) can lead to stable emulsion with that formulation I already heat it and then make it in fridge the emulsion is pretty stable (neutralised Carbomer helps also  for better stability) 
  • Paprik said:
    ketchito said:
    @Fekher You also need to add some base (sodium hydroxide for instance) to neutralize the Stearic acid, so it can work as an emulsifier.
    I have never understood this.  :/ So Stearic acid needs some base to be able to be emulsifier (saponification I reckon). But wouldn't it need higher pH to be able to maintain its properties? Meaning, if you would take the pH back down, it should "separate", shouldn't it? 
    Could you please explain it to me good man? :)
    Hehehe....Yes I have met others that did your course work, and they did not understand it as well.  In fact, they got violent when I tried to explain it....and I had to leave the group, as no one needs that in their life.  ;)
    Completly agree with Mr. Graillotion, about the reason leaving the group,  absolutely correct conclusion. Agree with all in discussion too!
  • @ngarayeva001, thanks! :) ... sorry, one more question, how much of a base do I need to add? (Let's say I would use Sodium Hydroxide). Is there any ratio? 
  • Paprik said:
    @ngarayeva001, thanks! :) ... sorry, one more question, how much of a base do I need to add? (Let's say I would use Sodium Hydroxide). Is there any ratio? 
    No...not an amount....the target is a pH.

    You're not gonna like that number...it is HIGH!  There are some old threads on the topic.
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