Increased water resistance for inorganic UV filters

The findings were presented at the Florida Sunscreen Symposium held last week in Lake Buena Vista.

The company found that adding two of their proprietary polymers in combination - the AMAZE XT polymer and a water soluble film forming polymer - improves the water resistance and SPF properties of inorganic UV filters such as titanium dioxide and zinc oxide.

"National Starch Personal Care tested several formulations in-vitro and in-vivo and found that when AMAZE XT was combined with DERMACRYL film forming polymer, the water resistant sunscreen products remained stable, and delivered water resistant protection" explained marketing manager, Maria Tolchinsky.

Titanium dioxide and zinc oxide are recognised by the FDA as particularly good UV filters as they have a broad spectrum of UV protection.

However the use of such inorganic filters is currently limited as they can be difficult to suspend in finished formulations without clumping, in addition to problems surrounding water resistance.

National Starch Personal Care claim to have found the solution to these on-going problems that will allow "formulators to achieve what they have always wanted, mainly the ability to incorporate mild and safe inorganic UV filters into water resistant baby sun care formulas, beach wear and daily wear formulas".

Tolchinsky explained that the implications of such an advance could be significant in light of the FDA's new regulations on suncare products.

"Pending regulations regarding the measurement of UVA may prompt formulators to look closer at formulating with broad spectrum inorganic UV filter, and at strategies that effectively boost the SPF value of finished formulations made with these filters" Tolchinsky said.

The FDA regulations concern the formulating, testing and labeling of over-the-counter sunscreen products, in particular introducing a rating system for UVA protection.

The UVA rating system works on a scale of one to four stars, with one star providing a low level of protection, two providing medium, three high, and four providing the highest level of protection available in over the counter sunscreens.

If the sunscreen is not awarded even a one star for low level UVA protection the proposals suggest that 'no UVA protection' be required on the front label near the SPF value - a ruling likely to prompt manufacturers to investigate the enhanced UVA protection that can be provided by inorganic filters.