Viscosity problems

I have the following formula:

PURIFIED WATER      76,6
VEGETABLE GLYCERINE USP      2,0
SUNFLOWER OIL      6,0
DIMETHICONE          3,0
TWEEN 80      2,3
SHEA BUTTER GLYCERIDE      0,1
CETOSTEARYL ALCOHOL NF      3,0
CETYL ALCOHOL NF      3,0
GLYCERYL STEARATE SE      2,8
PHENOXYETHANOL       1,0
FRAGANCE OIL      0,3

The formula should remain with a pH value between 5 and 6.5 but when adjusting with citric acid the viscosity is considerably reduced.

How can i prevent this effect?

With what other substance can I reduce the pH?

I appreciate your collaboration.

Comments

  • PharmaPharma Member, Pharmacist
    What is in your glyceryl stearate SE apart from glyceryl stearate (i.e. which compound makes it SE)?
  • Self-emulsifying as it contains a small amount 3-6% of potassium stearate.
  • That sometimes happens when you add Citric acid at the end. Maybe you could try adding it before the emulsification process?
  • ozgirlozgirl Member, PCF student
    You are trying to reduce the pH of your cream below what is recommended for your emulsifier (glyceryl stearate SE).

    A data sheet I came across for your emulsifier describes it as an emulsifier, stabilizer, opacifier, and an emollient in neutral to slightly alkaline anionic systems.

    If you wish to have your pH in the 5-6.5 range I would recommend a different emulsifier.
  • PharmaPharma Member, Pharmacist
    Self-emulsifying as it contains a small amount 3-6% of potassium stearate.
    Potassium stearate turns into stearic acid at lower pH and thereby looses its emulsifying property. You could try sodium stearate citrate which has a lower pka and hence better pH tolerance.
  • Hi...I am trying to manufacture dishwash liquids but my product is loosing it's vescosity after few weeks
    The formula which I am using is

    Acid Slurry- 80ml
    Castic Soda- 16gm
    SLES- 150ml
    Salt- 15gm
    Color- 1ml
    Perfume- 2ml
    Water - 720ml
  • Hi , you can try a little hpmc to your formula , hpmc can increase the viscosity  . Hydroxypropyl methylcellulose , also known as hypromellose and hpmc, cellulose hydroxypropyl methyl ether, is obtained by using high purity cotton cellulose as a raw material and special etherification under alkaline conditions
  • Thanks
  • I have the following formula:

    PURIFIED WATER      76,6
    VEGETABLE GLYCERINE USP      2,0
    SUNFLOWER OIL      6,0
    DIMETHICONE          3,0
    TWEEN 80      2,3
    SHEA BUTTER GLYCERIDE      0,1
    CETOSTEARYL ALCOHOL NF      3,0
    CETYL ALCOHOL NF      3,0
    GLYCERYL STEARATE SE      2,8
    PHENOXYETHANOL       1,0
    FRAGANCE OIL      0,3

    The formula should remain with a pH value between 5 and 6.5 but when adjusting with citric acid the viscosity is considerably reduced.

    How can i prevent this effect?

    With what other substance can I reduce the pH?

    I appreciate your collaboration.
    You can add lactic acid to reduce ph works better instead of citric 
  • yash42440 said:
    Hi...I am trying to manufacture dishwash liquids but my product is loosing it's vescosity after few weeks
    The formula which I am using is

    Acid Slurry- 80ml
    Castic Soda- 16gm
    SLES- 150ml
    Salt- 15gm
    Color- 1ml
    Perfume- 2ml
    Water - 720ml
    Thats a very strange formulation
    Take water mix nacl 30 gram 
    Then add sles 70 gram mix then add sls 10 gram add 30 gram Cocobetaine  then add labsa 20 gram dissolve in water in to mixer add naoh solution of 5gram them add citric 4gram and sodium citrate 4gram both  add tartaric acid 2gram add stpp 2 g plus edta 2g  benzoate 4g
    Them add tea 2ml glycerin 3ml dmdm 1 gram colur fragrance makes 1 litre
  • Can u please give the exact method of mixing....does TEA,DMDM,STPP,TRATARIC Acid and sodium citrate all need to be mixed
  • Ah. I had the same experience. I was given free sample of GMS-SE, it liquefies only in the presence of a little salt. Not low pH. Just salt. pH neutral.

    I think another offending one might be Tween 80. My almighty Xanthan Gum suddenly became liquid as though nonexistence. 

    Personally, I find steps of which goes in first matters not. In the past I was told like a broken record that I ought to make a gel with Carbomer first, add salts or cationic surfactant last. Ridiculous! Just my problem, of course. They probably able to jam in 20% Sodium Lactate without the slightest issue with the exact same Carbomer and at the same amount as I used. They either tell lie, or use supraphysiological and supernaturally high amount of Carbomer.

    Hydrophobically-modified Carbomer would not exist if the order of which ingredient goes in first worked. And that type of Carbomer is naturally more costly than old school Carbomer.

    @hernan1098
    Have you tried HEC or Hydroxy Ethyl Cellulose? It is a nonionic thickener. It works wonders and may answer your question! I have it but I hate its smell, it has vinegar scent.
  • The main problem is that at acidic, or even neutral pH, Sodium or Potassium stearate becomes free stearic acid which is both water insoluble and has no emulsifying properties whatsoever.

    I'd add some cationics (behentrimonium, cetrimonium) as emulsifiers, used along fatty alcohols (which you already have).

    What's the intended application for it?
    Is that a skin cream or a hair conditioner?
  • I modified the formula as follows:

    PURIFIED WATER     75,60
    VEGETABLE GLYCERINE USP     2,00
    CITRID ACID 10% 
    SUNFLOWER OIL
         1,00
         6,00
    DIMETHICONE         3,00
    TWEEN 80     2,25
    SHEA BUTTER GLYCERIDE     0,10
    CETOSTEARYL ALCOHOL NF     3,00
    CETYL ALCOHOL NF     3,00
    GLYCERYL STEARATE SE     2,75
    PHENOXYETHANOL      1,00
    FRAGANCE OIL     0,30

    The pH value is between 5 and 6.

    But the product takes a week to increase the viscosity.

    Can it be the homogenization rate?

    Can it be the order of addition?

    Is there any recommendation to work emulsifiers such as cetearyl alcohol, cetyl alcohol and glyceryl stearate, getting the best performance of each material?

    I really appreciate the collaboration.
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