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Practical tools for boosting

sunscreen efficacy

Yun Shao, Pascal Delrieu, Ed Bartholomey and David Schlossman

Kobo Products, Inc.

Sunscreen Symposium 2015


High SPF Sunscreen Trend

High SPF (50+) has become more desirable with increased consumer awareness of the risks of

harmful UV exposure. Market share of SPF 50+ products has experienced global growth.

Sunscreen boosters have become popular for efficacy enhancement and added skin benefits.

High SPF Sunscreen Products


Organic sunscreens Photostabilizer Anti-oxidants and bioactives

Banana Boat Ultra Defense Clear

Continuous SPF 110 UltraMist

Sunscreen Spray

Diethylhexyl

Syringylidenemalonate

Diethylhexyl Syringylidenemalonate, Aloe Barbadensis Leaf

Extract, Retinyl Palmitate, Ascorbic Acid, Tocopheryl Acetate

Coppertone Sport Sunscreen Lotion

SPF 75+

Diethylhexyl

Syringylidenemalonate

Diethylhexyl Syringylidenemalonate,Tocopherol (Vitamin E),

Retinyl Palmitate (Vitamin A), Sodium Ascorbyl Phosphate

Neutrogena Sport Face Lotion

SPF 70+

Diethylhexyl 2,6-

Naphthalate

Bisabolol, Artemia Extract, Saccharomyces/Zinc Ferment,

Saccharomyces/Magnesium Ferment, Saccharomyces/Calcium

Ferment, Saccharomyces/Sodium Ferment, BHT, Dipotassium

Glycyrrhizate

Neutrogena Pure & Free Baby

Sunblock Lotion, SPF 60+ Butyloctyl Salicylate

Ascorbic Acid (Vitamin C), Retinyl Palmitate, Tocopheryl

Acetate, Bisobolol, Pantothenic Acid, Avena Sativa (Oat)

Kernel Extract, Dipoassium Glycyrrhizate (Licorice Root)

High SPF Sunscreens – Ingredient Analysis


High SPF Sunscreen – Ingredient Analysis

Inorganic sunscreens Photostabilizer Anti-oxidants and bioactives

Replenix Ultra Sheer Physical

Sunscreen Spray SPF 50 ---

Ascorbic Acid, Ascorbyl Palmitate, Biotin, Camellia Sinensis (Green

Tea) Polyphenols, Emblica Officinalis Fruit Extract, Retinyl

Palmitate, Resveratrol, Tocopheryl Acetate, Ubiquinone

skinCeuticals Physical Fusion UV

Defense SPF 50 Butyloctyl Salicylate Tocopherol, Artemia Extract

DermaQuest SunArmor SPF 50 ---

Tocopheryl Acetate, Ectoin, Palmitoyl Oligopeptide, Palmitoyl

Tetrapeptide-7, Vitis Vinifera (Grape) Fruit Cell Extract,

Polygonum Aviculare Extract, Tocopherol, Ascorbic Acid, Ascorbyl

Palmitate

Dr Dennis Gross Sheer Mineral Sun

Spray SPF 50+ ---

Ascorbic Acid, Ascorbyl Palmitate, Biotin, Camellia Sinesis Leaf

Extract, Resveratrol, Tocopheryl Acetate, Ubiquinone

iS Clinical Eclipse SPF50+ Sunscreen --- Tocopherol, Tocopheryl Acetate

AVEENO® Natural Protection Lotion

Sunscreen with Broad Spectrum SPF

50

--- Bisabolol, Dipotassium Glycyrrhizate, Avena Sativa(Oat) Kernel

Extract


Transmittance Curves of Inorganic Sunscreens

320 360 400 440 nm 0

20

40

60

80

100

%T

• Antioxidants/bioactives do not affect the

UV attenuation of inorganic UV filters

• No effect on critical wavelength

• But they do greatly boost SPF to SPF50+

Sunscreen

product

Actives on label Est SPF based

on active% TiO2% ZnO%

Replenix NA 13.75 < 30

Dr. Dennis Gross NA 12 < 25

SkinCeutical 6 5 < 20

Eclipse 5.2 1.1 < 20

T% curves match the patterns of those

of TiO2, ZnO or their combo


Outline

I. Test and analysis the boosting effect of

Antioxidants and bioactive compounds

Organic sunscreen photostabilizers

Film formers / Light scattering particles

II. High SPF/PFA formulation strategy


Antioxidant &

bioactive compounds


Patents and Other Literature

• Claims that antioxidants can protect against free-radicals & cellular damage have become

widely accepted by consumers

• Projected demand for antioxidant-fortified products is increasing by about 8.5%-10.0% annually

(Cosmeceuticals, US Industry Study with Forecasts for 2012 & 2017, The Freedonia Group)

1. Antioxidants in sunscreens for Improved ROS protection

KM Hanson, C&T, Vo. 126, No. Oct. 2011

0.5% vitamin E and 0.9% diethylhexyl syringylidene malonate (DESM)

-- prevent ROS formation

-- Effect levels off at high SPF (70)

2. T Meyer et al. US 20090189090 A1, Jul 30, 2009

Method to test the composition for ability to inhibit both UV induced lipid peroxidation on skin

and ROS formation in the epidermis.


Patents and Other Literature

H Murad, US 5,804,168, Sept 8, 1998

- pharmaceutical compositions and methods for protecting and treating sun damaged skin

• mixture of botanical extracts to boost SPF of TiO2 Sunscreen up to ~ 10%

Olga Dueva, US 8465729 B2, June 18, 2013

- Sunscreen compositions with SPF enhancer (carotenoid )

• 16 Wt. % sunscreen agents and about 0.011% lutein

• SPF 29.65 was boosted to 31.5

JD Rigal, US 5618521 A, April 8, 1997

-Photoprotective/cosmetic compositions comprising antioxidants and filamentous bacterial extracts

… (i) at least one antioxidant and (ii) at least one extract of at least one nonphotosynthetic and

nonfructifying filamentous bacteria.

E Shim US 20080102045 A1, May 1, 2008

-Topical preparations containing antioxidant extracts of broccoli, green tea, and red tea … for the

protection of photocarcinogenesis


Discoloration of TiO2 by Antioxidants

Primary size: 10 nm 15 nm 60 nm TiO2

Composition:

TiO2 - coated with alumina and silicone 1.0 g

Ascorbyl palmitate (as example) 0.01g

Ester 6.5 g


Objective of Study

• Create an antioxidant ‘cocktail’ with the purpose of

meeting aesthetic requirements, low odor, light color, etc.

substantially boosting SPF of sunscreen compositions

compatible with inorganic UV filters

• Provide a practical guidance of use level and estimated boosting

effect


Compatibility with Nano TiO2

0 10 20 30 40

TNP50T7 - CONTROL

IBR-CLC

Argan Oil

Stay C 50 (Sodium Ascorbyl …

dl-alpha-Tocopheryl Acetate

IBR-AAC

Magnesium Ascorbyl Palmitate

IBR-TCLC in Jojoba Oil

Merlot Polyphenols

Ethyl Ascorbic Acid

Combray

dl-alpha-Tocopherol (USP)

Vitamin A Palmitate (1.7 MIU/g)

Covi-Ox T70C

White Tea Herbasol Extract …

FSG33 (Feruloyl Soy Glycerides)

Green Tea Herbasol Extract …

Green Tea Liposomes

Rosemary Oleoresin

White Tea Liposomes

Ascorbic Acid Fine Powder

Aquarox 10-302057

Ascorbyl Pamitate

• TNP50T7 – 50% Disp of 15 nm TiO2

w/alumina+methicone coating

• 5% addition to TNP50T7

• 5 days at RT

Discoloration (DE)


Antioxidants Selected for SPF Boosting

Two stable compounds are selected:

> Argan oil: produced from the kernels of the Argan tree; Contains antioxidants

such as tocopherols, phenols, carotenes….

> Tocopheryl acetate: a very potent anti-oxidant

A Booster Blend ATB was created with:

Argan oil – major component

VE acetate – minor component

Bisabolol – minor component, a natural anti-irritant, anti-inflammatory agent

Stable with 15 nm TiO2 for over 2 years (DE < 1.5)


Base W/O Formula for Testing Pt Percent INCI Name

1

18.53 C12-15 Alkyl Benzoate (And) Titanium Dioxide (And) Alumina (And)

Polyhydroxystearic Acid (And) Methicone

10.00 Cyclopentasiloxane

10.00 C12-15 Alkyl Benzoate (+ Boosters to tested)

3.00 Caprylyl Methicone

3.00 Polyglyceryl-4 Isostearate (And) Cetyl PEG/PPG-10/1 Dimethicone (And)

Hexyl Laurate

1.00 Trihydroxystearin

1.00 Glyceryl Stearate

1.00 Dimethicone

2

46.97 Water

1.00 Propylene Glycol (And) Diazolidinyl Urea (And) Methylparaben (And)

Propylparaben

1.00 Sodium Chloride

1.00 PEG-150/Decyl Alcohol/SMDI Copolymer

0.50 Polysorbate 20

3 2.00 Silica

TiO2: added as dispersion

TiO2%: 7

QS : C12-15 alkyl Benzoate

Control: Base formula with no

booster. Same through

this work

UV Protection testing:

Lab: AMA Laboratory

SPF/CW: FDA method

PFA: JCIA PPD method

Panel: 3 persons

Skin type II and III


Boosting Efficacy vs. Use Level

(Booster Blend ATB%)

22.5 27.5

32.0 36.5

32.1

38.5

0

10

20

30

40

0 1 2 3 4 5

SPF

Boosting effect is significant (up to 60%)

Boosting plateaus in the range of ~ 3 – 5%


Contribution of Components

Each component is extracted

from 3% of Booster blend ATB

Both anti-oxidant and anti-

inflammatory agent boost SPF

Contribution from each

component is fairly balanced out

at the ratio in Blend ATB 0

10

20

30

Control ARGAN OIL BISABOLOL VE Acetate

SPF

SPF Boost 22% 27% 17%


Boosting effect of each components is largely cumulative in this formulation

Component ratio ensures optimal synergy

Cumulative Boosting Effect

SPF

0

10

20

30

40

Control ARGAN OIL BISABOLOL VE Acetate 3% ATB

SPF Boost 22% 27% 17% 62%


Booster Blend ATB - Efficacy vs. TiO2%

TiO2% 7 12

ATB 3.0 4.2 5 6.5

SPF 36.5 32.1 38.5 52.3

SPF/TiO2% 5.21 4.58 5.50 4.35

At high TiO2 use level, boosting effect may be neutralized due to

less additive impact on skin cells

There is possibly a range for maximum boosting efficiency, which

corresponds to the finding in Hanson’s work


Boosting Inorganic Sunscreens

F11A F11C

% TiO2 6.0 6.0

% ZnO 4.6 4.6

% ATB - 5.0

SPF 31.40 44.93

% Boost - 43.1%

Booster blend ATB boosts the SPF of combined inorganic sunscreens

Booster blend ATB provides boosting in UVA as effective as in UVB

F12 F12A

% TiO2 4.8 4.8

% ZnO 3.4 3.4

% ATB - 3.6

PFA 7.49 10.09

% Boost - 34.7%


SPF Boost to Organic Sunscreens

F13 F13V

% Avobenzone 3.0 3.0

% Homosalate 15.0 15.0

% Octisalate 5.0 5.0

% Oxybenzone 3.0 3.0

% ATB - 5.0

SPF 40.9 54.8

% Boost - 34.0%

SPF boosting effect is still significant.

Boosting effect to high SPF (50+) formulas seems to be lower than that for low

SPF (30+) formulas.

No effect on critical wavelength was observed.

F15A F15B

TiO2 (230 nm)

ZnO (265nm)

Ocinoxate

% ATB - 5.0

SPF 44.0 57.5

% Boost - 30.0%

CW (nm) 373.7 373.8

3.60%

11.85%

7.50%


Organic Sunscreen

Photostabilizers


Organic Sunscreen Photostabilizers

• Butyloctyl salicylate (BOS)

> Stabilize Avobenzone

> Boost SPF effectively

> Helpful for SPF 30+ formulas

> lmax: 306 nm (UVB)

• Ethylhexyl Methoxycrylene-(EHMC)

> Stabilize Avobenzone

> Boosts PFA very effectively

> Helpful for PA+++ or higher

> lmax : 340 nm (UVA)


Boosting Effect of Butyloctyl Salicylate

• Control: base formula with 7% TiO2

• BOS was added in the form of TiO2 Dispersion

• SPF unit/BOS%: estimate to be 1.6

40%

0

10

20

30

Control Control + BOS (5%)

22.5

31.5

SPF


PFA Boosting effect of Ethylhexyl Methoxycrylene

PFA boosting is significant

The phtotostabilizer shows a great synergy with ZnO, and

expectedly TiO2 due to their scattering nature

Effective SPF boosting is also expected because of enhanced PFA

Formula F16 F17 F16H F17A

ZnO Primary size (nm) ~25 ~260

ZnO% 15% 15% 15% 15%

EMHC

(as part of ZnO Disp) -- 5.85 --- 2.86

PFA 7.5 11.7 5.52 10.8

% boost -- 56 --- 96


Film Formers &

Light Scattering Particles


N Herman, WO 2013036878 A1, Mar 14, 2013

-Polyamide compositions for personal care

• Disclose a hydrophobic polyamide made from a dimerized fatty acid and polyamine

• SPF increase: 160% in an SPF 30 & > 250% in an SPF 50+ formulation

Literature - Film Former

JR Strobridge, US 4917883, April 17, 1990, - O/W emulsion sunscreen composition

-… 0.5 and about 20 weight percent of a copolymer of ethylene and vinyl acetate together with a second

polymeric film forming agent which increases the substantivity of the film forming composition

TA Meyer, WO 2010129215 A2, Nov.11, 2010

-Enhanced efficiency of sunscreen compositions

-Compositions comprising UV blocking agents, a film forming polymer containing acid groups and a

neutralizing agent…


Film Formers Tested

Acrylates Copolymer (ACP)

- High MW,

- Water dispersible latex

- Film forming - irreversible

CH2 C CH2 CH

CH3

COOCH3 COOC2H5

x y

Hydrogenated Polycyclopentadiene

(HPCD)

- Low MW

- Oil soluble

- Adhesion promoter


SPF Boosting Effect of Film Former

0

10

20

30

40

Control ACP (2% active) HPCD (2%)

SPF

Both water dispersible and oil soluble film former helps boost SPF

The use level needs to be controlled to maintain good skin feel

SPF Boost 22% 53%


H Xing US 20120107253 A1, May 3, 2012

-sunscreen formulations using natural oceanic clay (aka marine glacial clay)

• Sunscreen formulations use the Natural Oceanic Clay when combined with sunscreen actives

such as zinc oxide, can provide significant enhancement in absorbance of UVA, UVB, and

UVC… ( clay size: 80 – 200 mesh; Boosting by in-vitro testing: 50 – 236% )

Sunsphere™ PGL from Dow, -- Technical Brochure Sept. 2003

• Hollow styrene/acrylic copolymer spheres (~250 nm) for enhancing UV protection

• 5% Sunsphere (~1.25% active) boosts SPF up to 70%

Literature – Light Scattering Agents


Formulation Strategy for High UV Protection

Antioxidants

Anti-inflammatory Sunscreen actives

Film formers

Light scattering

agents

Organic sunscreen

stabilizer

Zone


Part Percent INCI Name 1 45.70 Water

2 5.00 Niacinamide

1.00 Polysorbate 20

0.20 Methylparaben

3 4.00 Glycerin

0.20 Xanthan Gum

4 9.80 Zinc Oxide (And) Ethylhexyl Methoxycrylene (And) C12-15 Alkyl Benzoate (And)

Polyhydroxystearic Acid (And) Hydrogen Dimethicone

9.50 C12-15 Alkyl Benzoate

8.65 Butyloctyl Salicylate (And) Titanium Dioxide (And) Alumina (And) Silica (And) Stearic

Acid (And) Polyhydroxystearic Acid

5.00 Argania Spinosa Kernel Oil (And) Tocopheryl Acetate (And) Bisabolol

2.45 PEG-100 Stearate

1.00 Glyceryl Stearate

0.40 Shea Butter

0.10 Propylparaben

5 3.00 Silica

1.00 Polyacrylamide (And) C13-14 Isoparaffin (And) Laureth-7

6 3.00 Acrylates Copolymer (And) Water

High UV Protection Testing Formula (O/W)


Ingredient INCI %

Sunscreen actives TiO2 (40 nm) 3.54

ZnO (265 nm) 7.15

Antioxidant/ Anti-inflammatory Booster blend ATB 5.00

UV absorber/Stabilizer Ethylhexyl Methoxycrylene 1.37

Butyloctyl salicyalte 4.48

Film former Acrylates copolymer 1.5

Index Value Estimated value

without boosters

SPF 66 15 - 20

PFA 21 5

CW (nm) 380 380

Summary of Formula and Testing Scores


Antioxidants and bioactive compounds have great ability to boost the UV protection of

sunscreen formulas against both UVA and UVB. The boost effect can be cumulative.

However, their chemical compatibility with inorganic UV filters needs to be tested.

Certain organic sunscreen photostabilizers can also boost effectively SPF or PFA

depending on the absorption peak. They have good synergy with inorganic UV filters.

Both water dispersible and oil soluble film formers were tested to be effective.

SPF/PFA boosters of different mechanisms, when used in proper combination, can boost

protection multifold. This also helps to reduce the use of actives and improve the skin

feel and asethetics of sunscreen formulations.

Summary


Fred Ortiz

Kobo Application Lab

Acknowledgment

Date post:	05-Mar-2018
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