Best solvent for terpenes (terpinen-4-ol and nerolidol)

Hello Chemistry Experts!

Please share with me what you think would be the best/optimal solvent for a hair serum that includes terpinen-4-ol and nerolidol.

I have tried different solvents and so far Ethylhexyl Stearate seems to work best although it is too thin and needs thickening.

I’ve also tried fractionated coconut oil with mixed results (didn’t seem to be as potent and found that some of the serum started to solidify).

For regulations purposes here n Canada, I cannot use solvents already classified as “drugs” i.e. dimethicone, isopropyl myristate.

The purpose of the serum is to kill lice. When tested on live bugs, it has immediate effect in the ethylhexyl stearate however when applied to hair of infected people, it runs down the hair shaft and thus the head lice are not sufficiently immersed and escape neutralization.


If you can suggest a better solvent and substance that would thicken to more of a gel like substance, please tell me!

Or, if the Ethylhexyl Stearate is the best solvent, how to thicken to a gel like product to trap the bugs in the hair?

Thank you for your time and suggestions ☺️

Comments

  • MarkBroussardMarkBroussard Member, Professional Chemist
    @JbeanRaz:

    You can thicken your Ethylhexyl Stearate mixture with Phytol.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • @MarkBroussard
    Actually, we did try usIng phytol as a thickener with the fractionated coconut oil and it had no effect at all. 
  • MarkBroussardMarkBroussard Member, Professional Chemist
    Yes, but did you try it with the Ethylhexyl Stearate?
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details www.desertinbloomcosmeticslab.com
  • PharmaPharma Member, Pharmacist
    Is there a reason why you didn't try adding a standard oil thickener/gellant?
  • @MarkBroussard
    No we didn’t try it with the ethylhexyl stearate. We can certainly give it a go and see what happens. 

    After sampling different solutions on peoples’ hair, I’m leaning more towards a stronger hold gel like substance to trap the bugs and eggs in the solution rather than a more liquid gel like substance that seems to run down the hair and off the parasites.

    Do you think the phytol will work better on the ethylhexyl stearate?
  • @Pharma
    We're not at all averse to trying a standard thickener / gellant - just wondered if there is any in particular that is more effective. What is most important is to use the best solvent for the terpenes and then the best thickener for the mixture.

    Ideally a stronger hold gel like substance rather than a liquid gel that runs away from the scalp and down the hair shaft.
  • Bill_TogeBill_Toge Member, Professional Chemist
    for thickening, try some combination of hydroxystearic acid / hydrogenated castor oil / trihydroxystearin, they're reliable thickeners in this kind of solvent
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
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