need a preservative?

hello,
I thinking of this spray formula for dry skin and minor scratches.
Calophyllum Inophyllum seed oil       0.5%
Eucalyptus Globulus Oil                0.5
Glycerin                                       3
Panthenol                                  1
Aloe vera extract                        3
Peg 40 hydrogenated castor oil     3
Ethanol                                       40
Aqua                                            qs
are there other ingredients I should add to make it more effective?
Should i have a preservative since I have high amount of ethanol?
thanks


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Comments

  • PharmaPharma Member, Pharmacist
    40% ethanol make it self-preserving and there's no need to add additional preservatives (except probably an antioxidant).
    A spray for minor scratches? Ouch, that formula is going to hurt! Probably replace some of the ethanol with more glycerol? Even 10% ethanol are neither comfortable for scratches nor the best for a dry skin product IMHO.
  • PerryPerry Administrator, Professional Chemist
    If this is a product you intend to sell check the VOC regulations in your market.  If it is in the US, the VOC regulations would likely make it illegal to sell that product in California. This (along with flammability issues) is why you don't see alcohol used as a preservative more frequently.
  • thank you @Pharma @Perry !
    is it still self-preserving at 10% ethanol?

  • PharmaPharma Member, Pharmacist
    Not enough. Most microbes won't grow but won't die either. Think of wine which may have up to 15% ethanol before fermentation stops. At about 20% you're on the safe side but microbes will still be alive. Only above 40% makes them all die.
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