96 SUN CARE
UV-B filter Phenylbenzimidazole sulfonic acid (PBSA) and/or broad-spectrum filter BEMT in the oil and water phase, respectively (Table 3). According to the Guidelines for Evaluating Sun Product Water Resistance,3 manufacturers can claim a sunscreen is water resistant if more than 50% of the initial SPF in vivo is retained after two 20- minute baths. Formulation UV-DE-16-123- 2-10, containing the water-soluble UV filter PBSA, did not pass water-resistance testing. Water resistance could be improved (31% recovery of initial SPF with internal WR in vitro4
Table 2: Choice of emollients in relation to UV filter BEMT in either oil or water phase. UV filters
% by weight Emollients
Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) Ethylhexyl Triazone (EHT) Ethylhexyl Salicylate (EHS)
Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (BEMT) Tinosorb®
S Lite Aqua C12-15 alkyl Benzoate (Cetiol®
test) by replacing some of the PBSA in the water phase and some of the BEMT in the oil phase with the new aqueous BEMT dispersion in the water phase (UV-DE-16- 123-2-9). The in vivo water resistance (>50% recovery of initial SPF) was achieved by completely substituting PBSA with BEMT in the water phase (UVDE-16- 123-2-11).
Conclusion
By incorporating the broad-spectrum UV protection of BEMT in the water phase, manufacturers can offer high-SPF formulations that offer ease of spreadability, water resistance, and high efficacy across the UVA and UVB spectrum, all while feeling pleasant and light on the skin.
The aqueous BEMT dispersion Tinosorb S Lite Aqua is incorporated in the water phase at the end of the formulation process and requires neither solubilisation nor special homogenisation techniques. It can be cold-processed and pumped. No other UV filter currently on the market provides effective broad-spectrum UV protection in the water phase without a whitening effect, while also delivering water resistance for long-term skin protection. Tinosorb S Lite Aqua is the ideal UV filter for low-viscosity sun protection systems and face care products that feel light on the skin. Additionally, because it is free from both PEG/EO and aminomethyl propanol (AMP), it is suitable for use in applications for sensitive skin.
PC
References 1 Sohn M. Chapter 13, UV Booster &
Photoprotection, Extract from Principles and Practice of Photoprotection, Wang SQ, Lim HW.
2 The technology is subject of a patent application pending before the Patent Authority
3 Cosmetics Europe: Guidelines for Evaluating Sun Product Water Resistance, 2015
4 Sohn M, et al. In vitro water resistance testing using SPF simulation based on spectroscopic analysis of rinsed sunscreens. Int J Cosmet Sci 2017; 40(3): 217-225.
PERSONAL CARE ASIA PACIFIC C B UVB filters Dibuthyl Adipate (Cetiol® B) Propylheptyl Caprylate (Cetiol® Sensoft) Caprylic/Capric Triglyceride (Myritol® 312)
Table 3: SPF in vivoand WR in vitro and in vivo results. UV filters
Ethylhexyl Triazone (EHT) Ethylhexyl Salicylate (EHS) DBT
PBSA UVA filter
Broad- spectrum
SPF in vivo WR in vitro WR in vivo
Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB)
Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (BEMT)
Tinosorb S Lite Aqua AB) % by weight
UV-DE-16-123-1-5 UV-DE-16-123-2-9 2.5
2.0 5.0
4.0 –
12.0 10.0 –
5.0
2.5 2.0 5.0
2.0
10.0 –
5.0
10.0 5.0
% by weight
% by weight
3.0 – –
3.0 8.0 2.0 – 50 (60 in silico) 41% No WR (<50% SPF recovery)
Formulation example Phase
A 10.0
(2% active) 60
31%
% by weight
UV-DE-16-123-2-10 UV-DE-16-123-2-9 UV-DE-16-123-2-11 3.0 – –
3.0 4.5 8.0 3.0
5.0% 3.0% –
6.0% 3.0 12.5
(2.5% active) 62
86% 56% WR
(>50% SPF recovery)
INCI
Cetearyl Glucoside, Cetearyl Alcohol Disodium Cetearyl Sulfosuccinate Dibutyl Adipate
Propylheptyl Caprylate Caprylic/Capric Triglyceride
Phenoxyethanol, Ethylhexylglycerin Ethylhexyl Triazone (EHT)
Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) Ethylhexyl Salicylate (EHS)
Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (BEMT) Aqua
Glycerin
Dissodium EDTA Tinosorb®
S Lite Aqua (INCI: Bis-Ethylhexyloxyphenol
Methoxyphenyl Triazine (BEMT) (and) Acrylates/C12-22 Alkyl Methacrylate Copolymer)
10.00 November 2019
% by weight 4.00 1.00 5.00
10.00 5.00 1.00 2.00 2.50 5.00 2.00
50.30 2.00 0.20
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