SUN CARE
active particles. Accurate particle sizes of the produced CLP and purification steps in our process lead to stable aqueous suspensions. To control the behaviour of the active
ingredient, an initial investigation assessed the compatibility of the aqueous suspension containing CLP with ingredients commonly used in commercial sunscreens. Two parameters were found to be relevant for the performance of CLP in cosmetic formulations: Viscosity and Conductivity of the aqueous phase. A low viscosity and low salt concentration are favorable conditions for incorporating CLP. Utilizing the acquired information,
sunscreen formulations were developed, incorporating a variety of mineral and organic UV filters in the oil phase, along with CLP in the aqueous phase. Optical microscope analysis, centrifugal tests, and in vitro SPF measurements (based on DIN EN ISO24443) were employed to evaluate the various trials. It was shown that formulations containing
CLP consisted of smaller oil droplets compared to the control formulations without CLP. Stability tests were carried out in a centrifuge (3000 g/20 min/25°C) as well as 40°C over a period of six months. These stability tests confirmed long-term stability and the resistance of the formulation against phase separation and creaming. This can be explained by the strong droplet network created and stabilised by the CLP (Figure 2).
29
Control ■ with LignoGuard ■ +20%
60 50 40 30 20 10 0
+10 SPF 62
+25% +6 SPF
+50% +6 SPF
18 12 (OW,COSMOS) Zinc Oxide
Zinc Oxide (OW)
Octocrylene/ Avobenzone
Bisoctrizole (Tinosorb)
Figure 3: Adding 2-3% of CLP to a sunscreen formulation using zinc oxide dispersions as UV filters, a boost of six SPF points could be demonstrated. In a similar fashion, comparing two sunscreen formulations with common synthetic UV filters and CLP against a control showed a boost of 10-11 SPF points
In vivo SPF boosting of CLP versus control Furthermore, the in vitro assessments of the sunscreens showed promising results for the SPF-boosting ability of CLP for organic and mineral filters. Four sunscreen formulations containing
2-3 wt% of CLP were selected for in vivo SPF testing to measure the real-life SPF-boosting performance. These tests were conducted at an external institute, according to DIN EN ISO 24444. Compared to the control sunscreen
(not containing CLP), an SPF-boosting effect of up to 50% or 11 SPF points was achieved (Figure 3).
Conclusion In conclusion, the collaborative efforts of Lignovations and the Vienna University of Technology (TU Wien) have showcased a groundbreaking innovation in the field of sun protection with the application of CLP as SPF boosters in cosmetic products. As the cosmetic industry faces challenges related to
31 25 24 +11 SPF 35 +45% 52
www.personalcaremagazine.com
February 2024 PERSONAL CARE
in vivo SPF
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