Claiming "Nano" for Sunscreen Ingredients (Zinc Oxide, Titanium Dioxide) and FDA Regulations

English Answer:

Based on the FDA regulation in Thailand, you can only use the term "nano" for a product or ingredient if you have supporting documentation proving its particle size is 100 nanometers (nm) or smaller.

The ingredients you listed, specifically Titanium Dioxide 200nm EasyDisperse™ and Zinc Oxide 200nm EasyDisperse™, have a particle size of 200nm according to their names and product information. This size is larger than the 100nm limit required by the FDA to claim "nano".

Zinc Oxide (Micronized) is also mentioned, and it has an even larger particle size than 200nm. Therefore, adding 1% of Zinc Oxide (Micronized) will not allow you to claim "nano" for your formula.

In conclusion, based on the particle sizes of the ingredients you plan to use (200nm and larger), your formula does not meet the criteria set by the FDA for using the term "nano".

Regarding mixing without a grinding machine: Incorporating powdered ingredients like micronized zinc oxide can be challenging without proper equipment. Relying only on shaking or stirring may lead to poor dispersion, clumping, and an uneven final product.