The Transient Receptor Potential Vanilloid type 1 (TRPV1) receptor is one of the most well characterized pain-inducing receptors and has been recently identified as a valuable tool to predict eye stinging potential of surfactant based formulations. In this study we sought to predict eye stinging of nonsurfactant based cosmetic formulations by studying TRPV1 activity using the NociOcular assay. In the NociOcular assay, TRPV1 expressing neuroblastoma cells are exposed to test substance and TRPV1 activity is measured by acute increases in intracellular calcium. Three of the formulations induced stinging in the human test and were also positive in the NociOcular assay. The other four formulations evaluated were classified as stinging in the human test, but a conclusive determination could not be made in the NociOcular assay as the formulations were not fully soluble in assay buffers. The formulations were also evaluated in the EpiOcularTM assay, an established in vitro model for eye irritation utilized by the cosmetics industry. The Epiocular™ assay results did not correlate with the human sting data. Our data support that the NociOcular assay may be a valuable in vitro tool to predict human eye stinging sensation for cosmetic formulations. Future efforts seeks to further expand the applicability of the assay to product types other than surfactant based formulations.
October 17, 2019