The Development of Inorganic Ultraviolet Filters Exhibiting Improved Topical Retention on Human Skin for The Prevention of Skin Cancer

PROJECT SUMMARY / ABSTRACT This Phase II project is predicated on the NCI Phase I award 1R43CA236265-01 and is a resubmission. Problem to be Solved and Significance: Exposure to Ultraviolet radiation (UVR) is a risk factor for the development of skin cancer, and health care agencies recommend that sunscreens be used as a preventative measure. A major limitation of commercial sunscreens is the need to continually reapply to gain full benefit. This is because sunscreens contain UV filters that lack affinity with skin and are easily removed by normal wear. The development of durable filters with improved retention on skin has the potential to mitigate UV- mediated toxicities and remains a significant priority. Product and Long-Term Goal: Nanometics (d.b.a. PHD Biosciences [PHD]) is developing novel titanium dioxide and zinc oxide UV filters that contain a coating that interacts with skin proteins to improve topical retention time for up to 160 min. The novel UV filters are as photoprotective and safe as commercial UV filters and readily synthesized from inexpensive starting materials. They will be sold globally as ingredients for sunscreens and other topical products. It is anticipated that these UV filters will alleviate the need for constant product reapplication. Technological Innovation: The surface of commercial titanium dioxide and zinc oxide UV filters is covalently modified to contain a coating that interacts with skin proteins to improve topical retention time. The coating is designed to form a stable interaction at skin pH and can easily be removed by washing with soap and water. Specific Aim #1 Demonstrate that modification with HPGA does not influence the dermal penetration profile of the UV filters when evaluated on human skin explants. In this aim the dermal penetration profile of HPGA-Filters on cultured human skin will be investigated. Success Criterion: This aim will be successful upon determining that the HPGA-Filters do not penetrate to viable skin cells after a 48 h evaluation period. Specific Aim #2. Scale the chemistry, manufacturing and control processes to produce the HPGA-Filters on 75 kilogram batch sizes. The chemistry, manufacturing, and control (CMC) processes to produce HPGA-Filters in 75 kg batch sizes will be developed. Success Criterion: This aim will be successful upon optimizing the procedure to produce materials at 75 kg batch sizes with reproducible analytical profile and stability. Commercial Opportunity: The global market for UV filters is estimated to exceed $650 million by 2019. Phase II SBIR studies will include additional studies to confirm the safety on a larger number of volunteers; examine the performance against leading commercial sunscreens; and optimize the chemistry, manufacturing, and control (CMC) processes to produce the filters in multi-kilogram quantities. The technology is covered by a pending patent that protects the PHD commercial and development interests.PROJECT NARRATIVE Exposure to ultraviolet radiation (UVR) is a known risk factor for the development of skin cancer, which is the most common form of cancer in the United States. Currently available UV sunscreen filters lack affinity for the skin and must continually be reapplied. This Phase II SBIR proposal seeks to further the development of long- wear UV sunscreen filters with high affinity and improved retention on human skin. The novel filters provide extended protection from UV-mediated toxicities and their continued development remains a significant priority.