Infrared (IR) skin damage is the latest wave in Estée Lauder's skin protection efforts. While not the first to target it, the company could be the first to employ indium tin oxide (ITO) to shield against it.
Spanning wavelengths from 760 nm to 1 mm, IR is divided into three categories: IR-A (760 nm to 1400 nm), IR-B (1,400 to 3,000 nm) and IR-C (3,000 nm to 1 mm). Cho, et al., have reported that IR-A can penetrate epidermal and dermal layers and reach subcutaneous tissues without noticeably increasing skin temperature. IR-B and IR-C, on the other hand, are absorbed mostly in epidermal layers and cause increased skin temperature.
While the undesirable effects of UV on skin are well-known, less documented are the effects of IR. Chronic heat exposure has been shown to cause skin conditions similar to those in photo-aged skin. Also, a condition known as erythema ab igne results from IR exposure over long periods of time, presenting as hyperpigmentation, reticulated erythema, scaling and telangiectasis.
Cho has reported that repeated exposure to near IR has been shown in vivo to cause decreased type I procollagen expression and decreased expression of TGF-ß1, ß2 and β3. Also, that exposure to IR can also impact the expression of MMP-1 and cause the degradation of collagen and elastin fibers, decrease fibrillin production and more.
With this in mind, Lauder investigators explored the use of ITO to protect skin against IR radiation. According to the patent application, ITO is used in industry to coat windows, windshields or other substrates to reflect IR light, or to assist in defrosting of aircraft windshields when an electrical current is applied.
However, it has not previously been used in topical consumer products for protecting skin. This became the focus of the current invention.
Indium tin oxide-coated particles and compositions
U.S. Pat Application 20180271756
Publication date: Sept. 27, 2018
Assignee: ELC Management LLC (Melville, NY, USA)
Disclosed in this patent application are anhydrous topical compositions containing a solid or hollow particle ranging from 0.001 microns to 200 microns in diameter, and coated with ITO. ITO is reportedly a ternary composition of indium, tin and oxygen in varying proportions, typically as 74% indium, 18% oxygen and 8% tin by weight. According to the inventors, one advantage of ITO coated substrates is that they are transparent at visible wavelengths but opaque in the IR and UV ranges.
Patent application accessed on Sept. 28, 2018