Home Cosmetic Science Talk Formulating Needed help in dissolving glycerine based plant extract in oil.

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  • Needed help in dissolving glycerine based plant extract in oil.

    Posted by Emily2001 on January 14, 2021 at 3:20 am

    Dear All,

    I wish to solubilise glycerine based water soluble extract in oil.
    I tried using( as per manufacturers suggestion):
    1. Glycerine water soluble plant Extract: 3%w/w
    2. Polysorbate 80: 8%w/w
    3. Lauryl alcohol ethoxylate 7 moles: 14% w/w
    4. Iso propyl myristate: 30%w/w
    5. Light liquid paraffin: 45%w/w
    The client specifications are that the final product is to be marketed in oil form. The product formulation above is aesthetically perfect and the solution is stable. However, when tried on skin, it is showing minor irritation after 3-4 days. I have tried it on myself in the beard region( very less sample size I know! ). Skin feels like it is “stretched”. Is it due to polysorbate 80 and lae 7 concentration being more than threshold? Could either of the 2 be the reason for irritation? P.S. I do have dry skin but isn’t generally sensitive to chemicals. 
    Any suggestion for percentage reduction of any of above ingredients or easy hypoallergenic substitutes for the same?

    I have limited sample of the extract and really would want to take an informed decision into the formulation. 

    My further step: 

    If there is an irritant in the formula, substitute it or reduce it and add oils such as argan, jojoba, olive oil for emolliency by adjusting for LLP.

    Please suggest. 

    Thanks in advance :)

    Dr Catherine Pratt replied 3 years, 10 months ago 4 Members · 6 Replies
  • 6 Replies
  • Cafe33

    Member
    January 14, 2021 at 6:24 pm

    Laury l alcohol ethoxylate 7 moles: 14% w/w

    This is very high. I make a concentrated surface cleaner and I use 10% of the 9 mole version (70% ASM). Once diluted for use, it is simply 1%. I would not put 14% on my skin.  

  • Pharma

    Member
    January 14, 2021 at 7:56 pm
    Too much oil in water emulsifiers especially for a glycerol in oil formulation.
    You could try a pure d-phase (sucrose stearate and laurate are your friends) or a HIPE.
    High polyol content in your water phase (or pure glycerol instead of water) will shift the apparent hydrophilicity/lipophilicity balance or difference meaning you can’t use HLB and you’re likely lacking the necessary values for HLD. This may be the reason why your surfactants work against all odds.
    Replacing paraffin with a short polar and/or branched-chain oil might also help to reduce the amount of required surfactant and further lowers apparent HLB (increases chances for plyol/o over o/polyol emulsion).
  • Emily2001

    Member
    January 18, 2021 at 5:36 pm

    Thanks cafe33 for the opinion. I have been having that doubt about using lae7 but it is suggested by the supplier hence tried it. May be that’s the reason for the skin irritation.

    Thanks Pharma for the opinion. I shall try out sorbitan monolaurate and cctg and liquid paraffin.
    Any guidance on how much % we may need of the sorbitan monolaurate? I don’t mind trying but really have limited sample to try out.

    Please let me know your suggestions about the following:

    Next step:
    50% glycerine in water 3%
    Sorbitan monolaurate 7% ( maybe? I really have no clue here neither did I get any typical dosage reference )
    Cctg 30% 
    LLP: 60%

    Let me know if there is any suggestion you can provide for me to formulate this product.

    Thanks!

    Pharma said:

    Too much oil in water emulsifiers especially for a glycerol in oil formulation.
    You could try a pure d-phase (sucrose stearate and laurate are your friends) or a HIPE.
    High polyol content in your water phase (or pure glycerol instead of water) will shift the apparent hydrophilicity/lipophilicity balance or difference meaning you can’t use HLB and you’re likely lacking the necessary values for HLD. This may be the reason why your surfactants work against all odds.
    Replacing paraffin with a short polar and/or branched-chain oil might also help to reduce the amount of required surfactant and further lowers apparent HLB (increases chances for plyol/o over o/polyol emulsion).

  • Pharma

    Member
    January 18, 2021 at 8:11 pm
    You usually need less emulsifier than you the amount of inner phase.
    Maybe try PGPR (combined with a co-emulsifier), Cetyl PEG/PPG-10/1 Dimethicone, or Isolan GPS? I don’t think you’re going to be too happy with sorbitan laurate as sole emulsifier. However, according to THIS publication, an emulsifier system of Tween 80/Span 20 might actually work…
    BTW, your emulsion might turn out to be opaque or even transparent ;) .

    What is CCTG?

  • Emily2001

    Member
    January 19, 2021 at 11:19 am

    Thanks Pharma :)

    Let me try getting the materials you mentioned and also once with polysorbate 80.

    I really appreciate your technical help.

    Will keep you updated.

    Cctg stands for caprylic triglycerides.

  • Dr Catherine Pratt

    Member
    January 19, 2021 at 6:53 pm

    Watch your methodology Catherine Pratt

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