Sun exposure may result in skin photodamage, primarily due to irradiation by ultraviolet A and B rays (UVA and UVB, respectively). Presently, ranges of UV wavelengths thought to be damaging are considered to be 280-320 nm and 320-360 nm for UVB and UVA, respectively. Compounds or mixtures of compounds that absorb UVA and UVB radiation of these wavelengths are used as sunscreens to prevent skin photoaging. In particular, specific contributors to photodamage include inhibition of collagen biosynthesis and degradation of collagen due to activation of matrix metalloproteinases (MMPs) by UVA and UVB irradiation.
Researchers at the University of Michigan have discovered that the specific MMP-inducing UV wavelengths are 285-325nm for UVB and 360-400nm for UVA. Although the currently available UVB blockers adequately filter in this UVB range, those available for blocking UVA are less than desirable. This invention provides methods to formulate a desirable sunscreen, taking into consideration the medium in which the active compound with sunscreen effect will be carried, as well as the lower wavelengths at which the absorbed light is re-irradiated. Moreover, the discovery of the specific bands of irradiation which induce MMPs for collagen degradation can be leveraged for application of UV irradiation to treat fibrotic skin conditions such as scleroderma, scars and keloids which are characterized by the overproduction of collagen.
Applications and Advantages
- Development of compounds that more-nl-effectively block damaging wavelengths of-nl-UVA and UVB
- Treatment of skin conditions based-nl-on excess collagen
- Promotes self-healing for particular-nl-skin conditions, whereby irradiation with specific-nl-wavelengths of UV radiation induces MMPs to-nl-degrade the excess collagen