Sunscreen Spray Formulation Feedback and Shaking Requirement

Regarding your proposed sunscreen spray formulation and objectives:

The staff advises that sunscreen spray formulas must be very lightweight to be sprayed effectively.

1. Your Formula: Your proposed formula includes 25% Titanium Dioxide 15nm Liquid. The staff is unsure if this high concentration will allow the formula to be sprayed, as it might make the texture too thick. If it's too thick, you may need to reduce the Titanium Dioxide concentration or use a different type of sunscreen agent.
2. Pro Polymer / Carbomer: The staff states that thickeners like Pro Polymer and Carbomer are generally not suitable for spray formulas because they make the texture too heavy/viscous, preventing spraying.
3. Dimethicone / Cyclomethicone: These silicones are typically used in oil or silicone-based formulas that do not contain water and thus do not require shaking. For a water-based formula like yours, adding silicones might affect the texture and sprayability. The main focus for a spray is to keep it lightweight.
4. No Shaking Required: The staff explicitly mentions that sunscreen sprays containing dispersed sunscreen agents (like Titanium Dioxide) will require shaking before use to prevent sedimentation. Achieving a water-based spray that does not require shaking is generally not possible with this type of sunscreen. Only oil-based or silicone-based formulas without water can potentially avoid shaking.

In summary, while your proposed ingredients are valid, the concentration of Titanium Dioxide might be too high for a spray. Furthermore, achieving a water-based spray that doesn't require shaking is not feasible with dispersed mineral sunscreens like Titanium Dioxide due to sedimentation. Thickeners like Pro Polymer and Carbomer should be avoided.