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Sunscreen formulating/ Reducing whitecast
Hi all, I’ve been formulating a sunscreen recently and I can’t give every single exact detail but the following is the basis of my formulation:
I am finding a significant white cast at 2% TiO2 and even when I reduce the Tinosorb M to 4%, when they’re together. I have tried making creams at 2% TiO2 and 6% Tinsorb M alone (2 separately) and they are completely fine, but when put together it’s a disaster.
Does anyone have any advice in reducing the white cast that comes with it? Or anything else in my formulation that is glaringly ridiculous?P.S Using ethanol as a solvent is not an option for me!
P.P.S. We are looking to formulate something that is at least SPF50 PA+++ -
5 Replies
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If you’re using powdered Titanium dioxide try switching to a pre-dispersed solution.
Also consider small amounts of iron oxide to counteract the whitecast. I just recently came across a product that was a pure mineral sunscreen by a large brand that was doing just that. It seemed reasonable to me.
Not a seasoned professional here but most sunscreens I’ve seen use more than 20% active, you may need to up the sunscreens in your formula. But take this with a grain of salt, just speaking from observation.
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What kind of TiO2? Is it micronized? Also, it’s not generally a good idea to make sunscreen as O/W. You should at least add a film former.
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Thank you both for your responses :smiley:
Yes, the TiO2 is micronized, though we are looking into pre-dispersed solutions to see if it makes any significant difference.
Will definitely look into making an w/o emulsion too. I never knew sunscreens were generally w/o!
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Most of sunscreens (especially physical) are w/o. It helps with dispersion of particles and also w/o are water resistant which is a very useful quality for a sunscreen. Yours includes both physical and chemical sunscreens so I guess you can keep it as w/o but add something that would create a film on the skin and stops the product from shifting. People tend to rub their face a lot.
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@ngarayeva001 I’m not quite sure if adding a film former would actually prevent shifting. I guess this is why there’s a lot of testing behind sunscreens and they need to be FDA approved. But if o/w micelles are small enough and remain on the skin, they will essentially be “water soluble” and will wash off. I think the safest route is w/o from a molecular point of view. This is all a gut feeling, I’m not quite sure if micelles would remain or break during application, but I do know certain micellar structures are used for better absorption and transport of actives (some micelles can even be tagged for transport), so I’m assuming the structure remains for at least some time after application.
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