“Our goal is to find a simple, faster, more reliable in vitro method to verify the SPF of formulas containing organic UV filters and natural ingredients," said Soo In Yang, research scientist, Botaneco. “Whatever assay is adopted in the laboratory must be reproducible with the US FDA in vivo protocol. One such test method involves spectrophotometrics, the quantitative measurement of the reflection or transmission properties of a material.”
A study, now available in a peer-reviewed cosmetic dermatology journal, shows how spectrophotometric measurement of organic UV filters, embeded within an all-natural safflower oleosome, correlates with in vivo SPF testing. Specifically, Yang and others on the study team observed a high correlation for SPF 30 product models. They compared the spectrophotometric observation to a 2-subject in vivo clinical measurement, the results of which were further supported by a follow-up 10-person in vivo SPF study.
“The average value of the in vivo SPF test was SPF 31.98., where the spectrophotometric method provided an equivalent SPF average of 31.19. This demonstrates that the mean SPF values from the in vivo and spectrophotometric measurements are statistically identical, confirming the spectrophotometric method is reliable and comparable toin vivo SPF testing results,” said Yang.
An on-going shift toward natural ingredients is changing the way products function. Natural ingredients often behave much differently in formulations than synthetic ingredients, and that may impact traditional testing standards and protocols, said the company.