Physical, or Nonorganic, Blockers
Physical blocking agents are composed of sizable particles
that scatter, reflect, or absorb solar radiation in the UV,
visible, and even IR bands. Two inorganic particles widely
used in sunscreens are micronized zinc oxide and titanium
dioxide. The latest trend is to encapsulate these substances
in or combine them with vehicles such as carnauba
wax to achieve stable dispersion, ideal viscosity, and a
considerable increase in SPF.19-21