Herbal Essences shampoo with CSI and sodium benzoate

This is a Shampoo from Herbal Essences. The main anionic surfactant is CSI and the preservatives are sodium benzoate and sodium salicylate. As per my information these preservatives don't work in pH above 5 and this surfactant doesn't work in pH below 6. So 
does CSI work properly in pH 5 or this shampoo has high pH?

Ingredients/ingrédients: Water, Lauramidopropyl Betaine, Sodium Cocoyl Isethionate, Sodium Citrate, Sodium Lauroyl Sarcosinate, Fragrance, Citric Acid, Aloe Barbadensis Leaf Juice, Eucalyptus Globulus Leaf Extract, Histidine, Mentha Piperita (Peppermint) Oil, Mentha Arvensis Leaf Oil, Ecklonia Radiata Extract, Sodium Benzoate, Sodium Salicylate, Dimethiconol, Polyquaternium-10, Tetrasodium EDTA, Menthol.

Comments

  • What does your information say about SCI and pH below 6? I'm pretty sure it can work properly in pH 5
  • @Sincityfire ; i really like CSI and disodium laureth sulfosuccinate but the supplier say they are stable only in pH 6-8. I work in pH 5. I don't know if i should trust these informations.
  • @Abdullah Some surfactants can increase pKa of organic acids (like Benzoic acid), making them available in their acid form at pH a bit higher than expected. There are shampoos preserved with Sodium benzoate that with the right surfactant, can preserve Benzoaic acid's activity even at pH as high as 6.
  • @ketchito you mean this shampoo is preserved in pH 6 with sodium benzoate? 
    What do you say about stability of CSI and sulfosuccinate in pH below 6?
  • PhilGeisPhilGeis Member, Professional formulator
    ketchito is correct, and P&G has relied on that phenomenon as a an element of preservation  for most of its shampoos - but typically with EDTA and an isothiazolinone or benzyl alcohol.    Not aware salicylate at its pKa would help or shares the surfactant interaction phenomonon.
  • @PhilGeis which surfactants increase the pka of organic acids? 

    What is the lowest pH at which SCI and sulfosuccinate can work properly? 
  • PhilGeisPhilGeis Member, Professional formulator
    edited August 17
    Just benzoic - I understand sorbic is not so enhanced.
    https://www.sofw.com/en/sofw-journal/articles-en/47-home-care/1703-enhancing-antimicrobial-efficacy-of-sodium-benzoate

    I've no access to the article but I recall SLS and an isethionate
  • zeteinzetein Member
    Is salicylate here adequate against gram-negetave bacteria?
  • @PhilGeis thanks 
    What about ALS? 
  • PhilGeisPhilGeis Member, Professional formulator
    I dont have that information
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