Sodium Ascrobyl phosphate serum preservation

Hello 
Hope you are having a good day

So i am trying to make a vitamin c serum using sodium ascrobyl phosphate formula is

Sodium ascrobyl phosphate 5%
Hyaluronic acid 0.5%
Glycerin 0.5%
Propylene glycol 1%
Citric acid (to adjust ph)

Hyaluronic acid gives natural thickness to serum to no need of gums or thickener
The problem i am facing is after some time like a month i i can see some net like white substance is formed like we wet a tissue with water and sticks to walls of bottle its concerning
Using propylene glycol as a preservative since don't have many choices
Attaching the pic of available ingredients
Kindly help with choosing a better preservative
Thankyou.

Comments

  • EVchemEVchem Member
    the white powder might be SAP or the HA coming out of solution, if you put the substance into water does it dissolve?
  • PharmaPharma Member, Pharmacist
    Or it's a fungus... Let me rephrase: most likely, it's a fungus.
    1% propylene glycol plus 0.5% glycerol do not suffice for preservation! You'd need at least 10 times more of these to halfway keep microbes from growing.
    It is unlikely that any of your ingredients precipitate given their exceptional high solubility in water. Even if they degrade, their decomposition products remain highly water soluble. On the other hand, your serum is a great food for microbes and they will even feed on the two polyols if provided at such low concentrations.
    (I like smileys/emojis to underline personal feelings otherwise hard to express in a objective text like this. I really have the urge to post one here but alas, there's none which gets green in the face and throws up...)
  • Waleed636Waleed636 Member
    EVchem said:
    the white powder might be SAP or the HA coming out of solution, if you put the substance into water does it dissolve?
     I think its fungus
    Kindly take a look at provided list of ingredients and suggest a Preservative
  • Waleed636Waleed636 Member
    Pharma said:
    Or it's a fungus... Let me rephrase: most likely, it's a fungus.
    1% propylene glycol plus 0.5% glycerol do not suffice for preservation! You'd need at least 10 times more of these to halfway keep microbes from growing.
    It is unlikely that any of your ingredients precipitate given their exceptional high solubility in water. Even if they degrade, their decomposition products remain highly water soluble. On the other hand, your serum is a great food for microbes and they will even feed on the two polyols if provided at such low concentrations.
    (I like smileys/emojis to underline personal feelings otherwise hard to express in a objective text like this. I really have the urge to post one here but alas, there's none which gets green in the face and throws up...)
    Exactly thats what i was thinking
    Can you please take a look at the picture attached and suggest a preservative
    Thanks
  • PharmaPharma Member, Pharmacist
    The only preservatives on there are methyl- and propylparaben whilst salicylic acid and EDTA could be used as additives. Some of the products on that list are unknown to me.
    Could you use the two parabens for your serum? Yes. Though I would increase the amount of polyols too.
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