[free9s]

Thank you for your response!

I have a question regarding a glycolic acid serum formulation.

For example, if I have a solution with a pH of 4 (composed of water and other ingredients) then i add glycolic acid to the medium, maybe a significant PH drop can be noticed for example below 3 (e.g., pH = 2).

Given that the optimal pH stability range for glycolic acid is between 3 and 4, would this pH shift negatively impact the effectiveness or stability of glycolic acid?

[free9s]

Hello chemists and formulators,

I have a question about sunscreen. I want to make a mineral sunscreen using zinc oxide and titanium dioxide.

But I have a question about the type of emulsion that will make Zinc Oxide effective.

As far as I know, but I’m not sure, if we do a water-in-oil emulsion, that will make the Zinc Oxide effective.

But if we make an oil-in-water emulsion, the zinc oxide can migrate into the water, reducing its effectiveness, and this migration can be stopped by adding a water-in-oil type liquid emulsifier to that type of emulsion (Oil in water) is that right?

Can I do an oil-in-water emulsion using only an oil-in-water emulsifier?

will the zinc oxide be effective in this case?

Thank you.

[free9s]

Thank you for your answer.

But what do you mean by this : Basically depending on pH, part of Sodium Citrate will swap Citrate with Salicylic Acid and form soluble in water Sodium Salicylate + Citric Acid.

What do you mean by depending on ph, is it the ph of the final formulation or only after adding sodium citrate.

[free9s]

Thank you for your response!

I have a question regarding a glycolic acid serum formulation.

For example, if I have a solution with a pH of 4 (composed of water and other ingredients) then i add glycolic acid to the medium, maybe a significant PH drop can be noticed for example below 3 (e.g., pH = 2).

Given that the optimal pH stability range for glycolic acid is between 3 and 4, would this pH shift negatively impact the effectiveness or stability of glycolic acid?

[free9s]

Yeah I know that home sunscreens are not easy to make because you can’t get the right SPF.

But I want to make an SPF test in a lab so I’m asking about the type of emulsion so that the zinc oxide can give a good efficacy and protect from sun.

[free9s]

Thank you for your answer.

The active matter is the dry content which is around 64-68%

Is glyceryl oleate included within 64-68%?

[free9s]

Thank you for your response.

How did you you know that glucoside is about 34% in the blend?

And the ASM might be 18.7%?

Is there any calculation method you did?

[free9s]

Thank you.

[free9s]

Thank you for your answer.

But what do you mean by this : Basically depending on pH, part of Sodium Citrate will swap Citrate with Salicylic Acid and form soluble in water Sodium Salicylate + Citric Acid.

What do you mean by depending on ph, is it the ph of the final formulation or only after adding sodium citrate.

And what will I get in the final formulation

Salicylic acid serum or Sodium Salicylate?