In-vitro inhalation methods help with safe product development of cosmetic sprays

The ban on animal testing and increased characterization requirements for inhalation exposure pose challenges for the development and safety evaluation of spray products. In spite of this, major progress is still being made with in-vitro inhalation applications. Quantitative in-vitro to in-vivo extrapolations (QIVIVE) enable relevant in-vitro test environments, aerosol characterization and the estimation of inhalation exposure to be integrated into a single concept that can generate data to support the development and safety evaluation of cosmetic products.

Fraunhofer researchers have been investigating a spray product for room conditioning in hairdressing salons. They have carried out in-vitro inhalation experiments to investigate acute effects on the respiratory tract with a battery of tests using cells from human lungs and the P.R.I.T.® ExpoCube® exposure system patented at Fraunhofer ITEM. They have obtained dose-response relationships for the nebulized product that consider real application conditions. A QIVIVE approach was used to compare NOAELs (No Observed Adverse Effect Levels) obtained in vitro to results from exposure estimates based on a hairdresser’s eight-hour working day.

With this process, it was possible to calculate safety factors between the onset of a (potentially adverse) biological effect determined in vitro and actual human exposure as a function of exposure conditions, forming a basis for an initial safety evaluation. Furthermore, these effects could be attributed to a particular component of the spray product, allowing an alternative product formulation to further reduce the — already minimal — biological effects.

This case study therefore demonstrates the potential of integrating in-vitro inhalation and exposure estimation methods into a QIVIVE concept: The approach enables a quantitative assessment of potential biological effects and an identification of potentially harmful substances, and could thus make a crucial contribution to the development of safe products.