42 SUN CARE
TABLE 7: SPF IN-VITRO FOR ALL SIX FORMULATIONS (DIFFERENT EMULSIFIERS) Emulsifier A
Emulsifier B
Type of test Organic only
In vitro SPF (+/- SD) (actual)
25.14 (± 1.85)
Organic + aqueous TiO2
44.98 (± 6.45)
Organic only
26.33 (±4.09)
of protection along with lower photostability which is why it can be beneficial to combine with inorganic UV filters. However, when both UV filters are used together both mechanisms of protection are initiated leading to a synergy effect due to the physical protection mechanisms of the inorganic UV filters along with the absorption mechanisms of the organic UV filters, thus leading to more UV radiation being absorbed and reflected than if the products were used alone.1 In summary, it is useful to use a combination
of organic and inorganic UV filters because TiO2
provides a broad-spectrum base in which
to build upon. Organic UV filters are then used to build SPF and meet various regional requirements for UVA. The synergistic effect between inorganic and organic UV filters is beneficial in that it helps to achieve higher SPF and UVA but also gives a lower cost per unit of active. This also means that this can be a cost-effective method of formulating high SPF sunscreens. In addition it is beneficial to use the synergy
benefits of a combination of organic and inorganic UV filters as this allows for a higher solids loading within a formulation if the two types of UV filters are used in separate phases. There are numerous methods of incorporating a combination of both types of UV filters into a formulation. However, the most effective method of incorporation is to use an aqueous dispersion of TiO2
Ingredients
Organic + aqueous TiO2
66.01 (±4.88)
Emulsifier C
Organic only
25.54 (± 1.72)
Organic + aqueous TiO2
51.20 (± 4.23)
Emulsifier D
Organic only
28.49 (± 2.01)
Organic + aqueous TiO2
46.92 (± 2.38)
Emulsifier E
Organic only
28.43 (± 1.79)
Organic + aqueous TiO2
54.38 (± 2.98)
Emulsifier f
Organic only
29.38 (± 1.92)
Organic + aqueous TiO2
53.35 (± 5.32)
Aqueous TiO2■ Oil-based TIO2 4
3.5 3
2.5 2
1.5 1
0.5 0
One day Figure 4: TiO2 One week dispersions & BMDM in an O/W formulation over time
References 1 Lademann J Schanzer S Jacobi U. et al. 2005. Synergy effects between organic and inorganic UV filters in sunscreens. Journal of Biomedical Optics 2005; 10(1), 014008.
2 Cancer Research UK. 2020. Melanoma Skin Cancer Statistics. [online]: [Accessed 2 July 2020].
3 Lim H Draelos Z. 2009. Clinical Guide to Sunscreens and Photoprotection. Basic & Clinical Dermatology 2009; Volume 43. Informa Healthcare.
alongside oil-soluble organic UV filters. PC
4 Schneider S, Lim H. A review of inorganic UV filters zinc oxide and titanium dioxide.
TABLE 8: FORMULATIONS MADE FOR IN VIVO SPF ANALYSIS Phase A
Ethylhexyl Cocoate C12-15 Alkyl Benzoate Diethylhexyl Adipate Sorbitan Stearate
Glyceryl Stearate (and) PEG-100 Stearate Cyclopentasiloxane Octocrylene
B
Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine Aqua
Glycerin
Potassium Cetyl Phosphate Magnesium Aluminum Silicate Xanthan Gum
C D
Titanium Dioxide (and) Aqua (and) Polyglyceryl-2 Caprate (and) Sucrose Stearate (and) Simmondsia Chinensis (Jojoba) Seed Oil (and) Stearic Acid (and) Alumina (and) Glyceryl Caprylate (and) Squalane
Phenoxyethanol (and) Ethylhexylglycerin PERSONAL CARE October 2021
Photodermatology, Photoimmunology & Photomedicine 2018; 35(6): 442-446.
5 Manaia E Kaminski R Correa M Chiavacci, L., 2013. Inorganic UV filters. Brazilian Journal of Pharmaceutical Science, 49(2), pp. 201-209
6 Electronic Code of Federal Regulations (eCFR). 2020. Electronic Code of Federal Regulations (Ecfr). [online Accessed 7 July 2020].
7 Egerton T, Everall N, Mattinson J, Kessell L, Tooley I. Interaction of TiO2
nano-particles
with organic UV absorbers. Journal of Photochemistry & Photobiology A: Chemistry 2008; 193(1):10-17.
Organic only % w/w
1.00 6.00 5.00 1.00 1.50 1.00 6.00 4.00 77.00 3.00 3.00 0.40 0.10
– 1.00 Inorganic Only
(Aqueous TiO2 ) %W/W 1.00
6.00 5.00 1.00 1.50 1.00 – –
69.30 3.00 3.00 0.40 0.10
7.70
(Combination Organics only and aqueous TiO2 )
%W/W
1.00 6.00 5.00 1.00 1.50 1.00 6.00 4.00
59.30 3.00 3.00 0.40 0.10
7.70 1.00
www.personalcaremagazine.com One month ■
b-value
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92
