Home Cosmetic Science Talk Formulating Unstable Magnesium ointment

  • Unstable Magnesium ointment

    Posted by Batya on October 26, 2020 at 11:44 am

    Im Im Batya from Israel
    I formulate a magnesium chloride ointment. After a month or two i can see some unstable signs like separation, colour and scent changing too. Im using a jar to serve it.. and another thing im having trouble with is the ph. I send it to a lab and the ph was very low… 3.13.
    I cant manage to check the ph with regular mathoda, i think the ointment is too thick to separate for the mixture with purified water. Im a bit lost here..
    Ratios are
    Phase a: 
    Purified water : 25
    Magnesium chloride usp : 30
    Phase b:
    Shea butter : 10
    Soy lecithin :10
    Grapeseed oil : 13
    Beeswax : 3.
    Phase c:
    Vitamin e 1 and e oils 0.7
    Presevetive am25  0.6%
    Phase d : 
    Xantan gum:1.

    I hit the water and combine the magnesium at 70 Celsius degree. 
    Melting phase b in the meantime. When both reach 70 Celsius degree i pour phase a into phase b, slowly and mix with a wooden spoon. When its a bit cool (40 degree) i ad phase c and after the presevetive. Than i mix phase d together (glycerine with xantan gum until no little chunks anymore.
    Thats it. 
    Where is my weaknesses please help me 
    To fix my problems.

    ketchito replied 3 years, 8 months ago 2 Members · 1 Reply
  • 1 Reply
  • ketchito

    October 26, 2020 at 1:25 pm

    @Batya There are actually several issues here. The low pH is propbably causing your color and scent change. What’s the initial pH of your product? Maybe the product itself has a low pH from the start.

    Also, even though I’m not familiar with Lecithin as emulsifier, I see few things that can cause separation:

    1) xanthan gum might not be able to hold such a high level of electrolytes (from MgCl2)
    2) preservative system might not be sufficient since you’re using quite some amount of soy lecithin which itself is a source of contammination, exposing also xanthan gum to attack
    3) I read that lecithin alone doesn’t give stable emulsions, so maybe you could consider adding a co-emulsifier to the systems (in foods, usually whey or other related proteins are added for this purpose, but that will also increase your risk of contamination, so maybe a less “natural” co-emulsifier might help).

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