2 SOFW-Journal | 135 | 9-2009

COSMETICSUVA SUN PROTECT ION

photocarcinogenesis, largely mediatedby reactive oxygen species (ROS). Main-ly ultraviolet A (UVA) radiation (320-400nm) that penetrates into the deeperlayers of the skin (epidermis and dermis)is responsible for the generation of freeradicals (1, 2). The importance of ade-quate UVA protection has become ap-parent with improved understanding ofthe mechanism of UVA-induced damageto tissue. Thus, photoprotection, andmainly UVA protection, is crucial for pre-venting the undesired effects of sun ex-posure through sunbathing or in a dailyskin care regiment. Photoprotection ismainly achieved by sun avoidance, cloth-ing and the use of sunscreens containingorganic and inorganic UV filters. Accord-ing to several studies, it is possible toconfirm that the regular use of sun-screens may reduce the harmful effectcaused by long-term exposure to UVBand UVA radiation (1, 3). The urgent needto introduce UVA protection also in dai-ly care products, especially for face daycream and hand cream, is a consequenceof the understanding of the cumulativedamage caused by UVA radiation to theskin. The efficacy of photoprotection in cos-metic products depends on four key fac-tors:

1. Technology to reduce the amount ofbroad spectral range of UV radiationthat reaches the skin, possibly withoutchanging the natural sun spectrumquality (spectral homeostasis). UV fil-ters are the heart of this technology,but also the formulation of the sun-screen plays a crucial role. The best UVfilter combination cannot perform, if

U. Osterwalder*, K. Jung**, M. Seifert**, Th. Herrling**

Importance of UVA Sun Protection: A Comparative Analysis of Different Quality Control Methods

� Abstract

The globally accepted standard for theassessment of UV protection by a sun-screen formulation is the determinationof its Sun(burn) Protection Factor (SPF).The SPF as a measure of UV-damage isemphasizing the impact of the shorterwavelength UVB radiation which with itshigher energy is the main cause of sun-burn and direct DNA damage. The effectscaused by the longer wave UVA range areonly minor with respect to sunburn yetmajor in relation to induction of pigmen-tation, to the formation of secondaryradicals and thus also to DNA alterationas well as long-term effects on skin func-tions such as premature aging and ma-lignity. Currently, the efficiency of UVAprotection is assessed via the PersistentPigment Darkening (PPD) method in vivoand by several in vitro methods, all basedon the measurement of the UV trans-mission through a layer of sunscreen ap-plied onto a UV transparent support.Contrary to the SPF method all theselatter UVA methods are lacking a rele-vant biological endpoint. An alternativemethod that refers directly to a biologi-cal response mainly induced by UVAradiation is the Radical Skin ProtectionFactor (RSF) where UV – induced freeradicals (Reactive Oxygen Species; ROS)are measured by Electron Spin Reso-nance (ESR), ex vivo in irradiated skin ex-plants.The aim of this study was to investigatewhether the reduction of free radicalgeneration is a measure for protectionagainst UVA radiation. 16 commercial sun-screens in the SPF range of 15-60 and 6daycare products of SPF 4-15 with vari-

able UVA protection were used to checkthis hypothesis. Besides the RSF value,the UVA-PF was determined in vitro, andSPF and UVA-PF were also assessed in sil-ico by the sunscreen simulator comput-er program. There is an average relationUVA-PF = 0.33 SPF over all samples con-firming that half of them comply withthe EC UVA recommendation. Amongthe half that complies the average rela-tion UVA-PF = 0.50 SPF was found. TheRSF is similarly correlated with the SPF;RSF = 0.4 SPF over all samples and RSF =0.55 SPF for EC-UVA compliant half ofthe samples, but the variance is muchhigher leading to a correlation coefficientclose to zero. The RSF was found to be re-lated to the UVA-PF, RSF = (1.0-1.3)UVA-PF, depending on the SPF range ofthe samples. The deviation from the per-fect correlation can be explained by thevarious influence factors on both meth-ods. In conclusion, the RSF is able to pro-vide the information on UVA protectionwhich is required in addition to the SPF.On the other hand in vitro assessment ofUVA protection can also serve as a valu-able estimate of the RSF.

� Introduction

UV radiation is the main culprit of sev-eral types of skin cancer and a key fac-tor responsible for photoaging (1). Skincancer and photoaging changes may re-sult from ultraviolet (UV)-induced oxi -dative stress that induces a cascade ofbiochemical and biophysical reactions inthe skin. Erythema is the most apparentresult of the sunburn reaction, but themost serious results are photoaging and

the formulation is not right, i.e. spreadsuniformly and sustainably over theskin.

2. Assessment of the performance of asunscreen regarding SPF and UVAprotection, i.e. the quantity (level)and the quality (breadth) of the pro-tection. This paper is dealing with theassessment of UVA protection of sun-screens.

3. Standards for UV protection, e.g. thewell established standards in Australia(4), United Kingdom (5) and Japan (6)and as recently released by the Euro-pean Commission (7) and the US Foodand Drug Administration (8) for SPFand UVA-Protection.

4. Compliance by the sunscreen user.The best sunscreen provides only in-sufficient protection if not applieduniformly, not in the right quantity ornot at all.

Compliance is the most important keyfactor. The first three key factors all in-fluence compliance. Technology affectsthe interaction of the components of thecosmetic products with the skin and thusthe homogeneous distribution of the UVfilters on the skin’s surface and most im-portantly if the user likes the product.The topic of this paper is UVA assessment.The way UVA assessment is achieved andcommunicated can increase the credi-bility of a sunscreen, e.g. a relevant end-point such as reduction of free radicalsin the skin is desirable and may becomeas important a message as the »not-get-ting-sun-burned« message which is basedon the endpoint of the well establishedSPF measurement. Among the several methods (9, 10) to as-sess the efficacy of sunscreens, there aretwo main groups: in vivo-measurementsthat use biological endpoints such aserythema (SPF method) and pigmen -tation (permanent pigment darkening,PPD method), and in vitro-measurementsthat measure the transmission spectra ofsunscreens applied to a carrier. The in vivo measurements have two maindraw-backs: firstly it is impossible to usethe same biological endpoint for bothUVA and UVB induced damages. Since

the SPF describes mainly UVB protection,especially as it is designed in the clinicallaboratory testing, a separate assessmentof the UVA protection is required. Persis-tent Pigment Darkening (PPD) is thecommonly accepted in vivo method, al-though the PPD effect is not relevant inreal life, unlike the erythema. The arbi-trary classification in two ranges of UVirradiation does not reflect the biologi-cal effects and reality. Secondly, the useof test persons brings along problems ofhigh variability of the results and ethi-cal conflicts. To overcome these problems related to invivo measurements, the in vitro determi-nation of the protective effect of sun-screens has been used for many years. Allmethods have in common the determi-nation of the transmission of UV radia-tion that passes through the test formu-lation applied on a carrier (e.g. quartz orPMMA). Especially ratio methods such asUVA/UVB or UVAI/UV are very robust inpredicting correctly the relative UV pro-tection provided by a sunscreen (12). Yet another method to assess sunscreenperformance is the in silico calculation.Based on the absorption spectrum ofeach UV filter present in a sunscreen andthe assumption of a film-model of thesunscreen distribution on the skin, bot-tom-up calculations can be carried out

(13, 14). The parameters in the sunscreenfilm model (e.g. step-film or another dis-tribution) are adjusted by sunscreen ref-erence samples of known (in vivo) SPF.Experience shows that such in silico cal-culations predict the SPF and the UVA in-dices of a sunscreen often more accuratethan a transmission based in vitro mea-surement (15). These methods allow obtaining repro-ducible measurements without interfer-ence of biological variability. However,exactly this absence of biological influ-ence, i.e. the interaction of the appliedsunscreen formulation with the skin, isthe main deficiency of the in vitro mea-surements and in silico calculations.There are two methods that try to over-come the defects of both in vivo and invitro measurements by combining ele-ments of both: one is the COLIPA UVAGuideline 2007 that determines theUVA-PF in vitro under consideration ofthe in vivo SPF (11), and the other theRadical Skin Protection Factor (RSF) us-ing a completely different approach bymeasuring the UV-induced free radicalsin skin, directly detected in skin biopsysamples. (16)Fig. 1 shows the effectiveness-range ofthe SPF, UVA-PF and RSF method. TheErythema Effectiveness Spectrum calcu-lated after the CIE action and sun spec-

4 SOFW-Journal | 135 | 9-2009

COSMETICSUVA SUN PROTECT ION

Fig. 1 UV Effectiveness Spectra: Erythema, PPD and Free Radical Formation

18

tra is located mainly in the UVB range(Effectiveness Spectrum = Action Spec-trum x Sun Spectrum) (17). The effec-tiveness spectrum of the Free RadicalFormation is depicted schematically bytransformation of the erythema spec-trum mainly into the UVA I range (340-400nm). A recent publication of an ef-fectiveness spectrum for free radical for-mation is added to the figure confirmingthis assumption (18). This figure showsthat SPF and UVA-PF or RSF togethershould provide the information aboutprotection in the full UVB/A range. Fur-thermore, we expect a good correlationbetween RSF and UVA-PF.

� Materials and Methods

In the present work these two methods,UVA-PF in vitro and RSF, have been usedto determine the sunscreen efficacy of22 cosmetic market formulations. TheirUV filter composition was determined byHPLC analysis (Table 1). All productscontained organic and/or inorganic UVfilters. The cosmetic products includedoils, lotions, and sprays. The formulationswere O/W or glycerin-based. Among these22 products, 16 were declared as sun-screens and 6 were daily care products. From the UV filter concentrations, the SPFin silico was calculated (14) and com-pared to the labeled SPF. The UVA-PF wasdetermined according to the COLIPAguideline 2007 (11). The RSF factor wasdetermined as described by Herrling et al(16). In brief, the test products were ap-plied on skin biopsy samples (pig skin,ear) at 2 mg/cm2 labeled with a radical in-dicator, UV irradiated using a sun simu-lator and the amount of free radicals inthe skin was directly determined by ESRspectroscopy.

� Results and Discussion (Table 1)

UVA-PF determination(in vitro, COLIPA 2007)The UVA-Protection Factor was deter-mined afccording COLIPA 2007 guideline.Only half of the products fulfill the Eu-ropean Recommendation on UVA protec-tion that requires the UVA-PF to be atleast 1/3 of the labeled SPF (marked with»UVA-COLIPA-logo«, 8 out of 16 sun-

SOFW-Journal | 135 | 9-2009 5

COSMETICS

6 SOFW-Journal | 135 | 9-2009

COSMETICSUVA SUN PROTECT ION

Table 1 Studied sunscreens (1-16, yellow) and daily care products (17-22), green

N° UV Filter Amount SPF UVA-PF COLIPA RSFUVB.....UVB/A......UVA (%) Label calc.

OC 5,501 BMDBM 4,8 15 15,8 8,3 10,6

DTB 1,5

OC 8,102 BMDBM 3,0 20 18,6 10,2 16,5

TiO2 2,2

TiO2 4,2BMDBM 4,6

03 BEMT 3,0PBSA 2,1 DTB 2,0EHT 1,6

04 TiO2 5,2 20 6,3 2,4 2,4TiO2 2,3OC 9,1

BMDBM 2,5DTS 1,5

TDSA 0,5EHS <0.1

BEMT <0.1EHT <0.1

EHS 5,0TiO2 2,8

BMDBM 2,5OC 2,3

BEMT 2,0EHT 1,0DTS 0,5

ZnO 0,1

TiO2 6,3BEMT 2,5

EHMC 10,0BEMT 2,0MBBT 2,0

TiO2 0,1ZnO 0,1

EHMC 10,0MBBT 4,0

MBBT 7,4EHMC 10,0TiO2 5,9

DHHB 7,0ZnO 0,7

OC 10,0BMDBM 5,2

TiO2 2,8BEMT 1,5

OC 9,1BMDBM 5,2

MBBT 1,4BEMT 0,5

55

20

40

25

25

55

30 30

63,1

20

23,2

27,7

20,3

28,6

28,5

05

06

07

09

10

11

08

45,7 10,0

10,9

12,1

28,2

16,4 10,6

7,8

5,8

6,1

16,5

13,0

23,1

6,3

13,0

11,3

6,8

20 23,212 10,9 11,3

SOFW-Journal | 135 | 9-2009 7

COSMETICSUVA SUN PROTECT ION

N° UV Filter Amount SPF UVA-PF COLIPA RSFUVB.....UVB/A......UVA (%) Label calc.

OC 8,0BMDBM 2,0

13 TiO2 2,0 25 21,1 9,9 27,1BEMT 1,0

EHT 0,3

OC 9,1TiO2 2,9

14 BMDBM 2,5 20 23,8 11,2 18,2DTS 0,5

TDSA 0,5

15 PABA 5,5 20 8 1,1 2,1OCR 10,0

16 EHMC 7,8 20 23 3,9 4,1DHHB 1,4

EHMC 8,017 PBSA 1,8 15 13 1,5 3,6

TiO2 0,8

EHMC 7,2BMDBM 2,1

PBSA 1,5TiO2 0,3

OCR 1,6BMDBM 0,3

OCR 5,0BMDBM 3,1

TDSA 2,1DTS 1,5

EHMC 5,0BMDBM 1,0

OCR 4,1EHT 3,1

22 BMDBM 1,5TiO2 0,3

MBBT 0,3

15

15 15

4

8 8

17

3

18

19

20

21

3,6

2,1

2,5 7,5

12,3 11,8

5,1

3,9

15 18 5,0 8,0

Abbrev. Use INCI UV absorber(x)

UVB UVABEMT 7 Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine X XBMDBM 14 Butyl Methoxydibenzoylmethane XDBT 1 Diethylhexyl Butamido Triazone XDHHB 2 Diethylamino Hydroxybenzoyl Hexyl Benzoate XDTS 4 Drometrizole Trisiloxane X XEHMC 6 Ethylhexyl Methoxycinnamate XEHS 2 Ethylhexyl Salicylate XEHT 4 Ethylhexyl Triazone XMBBT 5 Methylene Bis-Benzotriazolyl Tetramethylbutylphenol X XOC 11 Octocrylene XPABA 1 para-Aminobenzoic Acid XPBSA 2 Phenyl Benzimidazole Sulfonic Acid XTDSA 4 Terephthalylidene Dicamphor Sulfonic Acid XTiO2 13 Titanium Dioxide X (X)ZnO 2 Zinc Oxide X X

screens and 3 out of 6 daycare products).In the column of the UV filters the ab-sorption range of each UV filter is indi-cated, UVB, UVA or in between forbroad-spectrum UV filters. There is onlyone sunscreen and one daily care prod-uct that contain neither a UVA nor abroad-spectrum UV filter (No’s 15 and17). Recent surveys carried out in 2009 showthat compliance of sunscreens increasedwhereas the majority of the daily prod-ucts still provide inferior UVA protection.The reason for low UVA protection is on-ly in 3 cases the lack of UVA or broad-spectrum UV filters (samples 4, 15 and17). In 9 out of the 16 sunscreens and 5out of the 6 daily products BMDBMis found as UVA filter. Two of those lat-ter cases are in combination with EHMCwhich makes the formulation unstable(daycream samples 18 and 21). All sam-ples with SPF > 20 that fulfill the UVA-PF/SPF > 1/3 criterion (marked withUVA-logo) contain modern broad-spec-trum or UVA filters (BEMT, DHHB, DTS,MBBT or TDSA).

SPF calculation (in silico)It is possible to estimate the sunscreenperformance based on its UV filter com-position. The sunscreen simulator pro-gram (13, 14) is based on the spectra ofthe individual UV filters in diluted solu-tion or dispersion. In addition an irregu-lar sunscreen film assumed to simulatethe real situation on the skin and to cal-culate the transmission. In 20 out of the22 products (90%) investigated in thisstudy the calculated SPF value is close tothe labeled SPF, i.e. not further off thanwhat we could expect as variation be-tween in vivo SPF values tested by dif-ferent testing laboratories. In two out ofthe 22 cases the calculation underesti-mates the SPF by far, i.e #4 (SPF 20, calc.6.3) and #15 (SPF 20, calc. 8). This maybe explained by the special compositionand formulation of the two productswhich apparently perform much betterthan expected. Sample # 4 is special be-cause it contains only Titanium Dioxideas UV filter. It is also known from in vit-ro SPF measurements that the perfor-mance of inorganic UV filters TiO2 andZnO tends to be underestimated. Fur-

thermore there exist different grades ofmicrofine TiO2; not all of them are re-flected in the sunscreen simulator. Sam-ple # 15 only contains the organic UV fil-ter PABA in an alcohol based formula-tion. This alcohol based formulation ap-

parently allows the spreading of the UVfilter on the skin much more uniformlythan in oil-in-water based emulsionswhich served as references to calibratethe model parameters of the sunscreensimulator program.

8 SOFW-Journal | 135 | 9-2009

COSMETICSUVA SUN PROTECT ION

Fig. 2 Correlation between UVA-PF and labeled SPF (all samples, r= 0.67). The linearcorrelation line corresponds to the EC recommendation UVA-PF = 0.33 SPF. Abouthalf the samples of the study comply (above the line) and the other half does not(below the line)

Fig. 3 UVA-PF = 0.5 SPF (r=0.91) for products compliant with EC-UVA recommen-dation

Our productsfor your beauty

DexpanthenolPanadoxine Pdl-alpha Tocopheryl AcetateVitamin A PalmitateNiacinamidePBSA-Phenylbenzimidazole Sulfonic AcidOMCX-Octyl Methoxycinnamate

OctocryleneBisabololCoenzyme Q101,3 Butylene GlycolHyaluronic AcidL-HydroxyprolineAmino Acids

Am Wehrhahn 5040211 Düsseldorf / Germany

Telefon 0049 (0)211 - 175 45 0Fax 0049 (0)211 - 175 45 447E-mail dfc@kyowa.deWeb www.kyowa.eu/daiichi

Kyowa Hakko Europe GmbHDaiichi Fine Chemical Division

BMDBM-Butyl Methoxydibenzoyl Methane

*

The calculation program can also be usedto determine the various UVA indicessuch as UVA-PF, UVA/UVB ratio, criticalwavelength etc. The calculated UV trans-mission profile is shown for four select-ed samples in Fig. 6.

Correlation UVA-PF vs SPFAlthough the SPF does not tell us aboutthe UVA protection of a sunscreen, thereis a correlation between UVA-PF and SPFin recent EU products according REC.Whereas it is possible to achieve SPF val-ues below about 15 without UVA pro-tection, this is not the case for higherSPFs since the UVA transmitted in the UVArange is also erythema-active (Fig. 1). Inthe study the correlation between UVA-PF and SPF is about UVA-PF = 1/3 SPFwith a correlation coefficient over all 22samples of r=0.67 (Fig. 2). This meansthat about half the samples comply withthe 2006 EC-UVA recommendation (16).By introducing the UVA recommendation(UVA-PF > 1/3 SPF) the Euro- pean Com-mission (EC) forced the UVA-PF to corre-late better with the SPF. This can be seenby correlating only the upper half of thesamples that all fulfill the EC recom-mendation. The average UVA protectionexpressed as the UVA-PF becomes halfthe SPF. i.e. UVA-PF = 1/2 SPF with aneven better correlation coefficient of0.91 (Fig. 3).The average RSF is similarly correlatedwith the SPF, i.e. RSF = 0.4 SPF for all sam-ples and RSF = 0.55 SPF for all EC-UVAcompliant samples, but with much high-er scattering leading to a correlation co-efficient close to zero. This higher scat-tering may have several reasons whichare discussed below.

RSF determination and correlation RSF vs UVA-PFThe RSF values are in most cases simi-lar to the UVA-PF. There is a correlationRSF = 1.1 UVA-PF over all samples, but notas good as expected; the correlation co-efficient over all samples is only r = 0.64(Fig. 4a). There seem to be a few outliers.A better correlation is achieved by elim-inating the effect of the SPF level; onlysamples of SPF 20 were plotted in Fig. 4b.The UVA-PF range still varies from UVA-PF1.1 to 16.3 in this series of 8 products witha strong correlation RSF = 1.3 UVA-PF

(r = 0.89). The scattering that leads to apoorer correlation comes mainly from thesamples with SPF > 20. Fig. 4c shows theexpected correlation RSF = 1.0 UVA-PF,but with a very high variance (r = 0.0).Possible reasons for this high varianceare discussed below.

Correlation N (Photons, skin exposure) vs N (Free Radicals, measured in skin)(Fig. 5)There is an obvious correlation betweenthe UVA-PF and the RSF. Whereas the

UVA-PF quantifies the number of pho-tons penetrating the skin, the RSF deter-mines the number of generated free rad-icals in the skin. Both quantities are in adirect correlation. The quantity of pho-tons determines the number of generat-ed primary free radicals in the skin suchas super oxide anion (O2-•) and hydroxylradi- cals (•OH). The number of daughterelements (secondary free radicals) likedifferent forms of lipid radicals and oth-ers are influenced by the AntioxidativePotential (AOP) of the individual skin

10 SOFW-Journal | 135 | 9-2009

COSMETICSUVA SUN PROTECT ION

Fig. 4 a RSF = 1.1 UVA-PF or all 22 samples ( r = 0.64)

Fig. 4 b RSF = 1.3 UVA-PF for 8 samples at SPF 20 (r = 0.89)

(16). The AOP of the whole skin is deter-mined by an intrinsic and extrinsic AOP.The extrinsic AOP can be influenced bythe cosmetic product containing addi-tionally antioxidants. The AOP of the skininfluences finally the correlation be-tween the UVA-PF and the RSF. This in-fluence is expressed by the correlationfactor (Cf):

N(FR%) = Cf • N(Photon%) whereasCf > 1 means free radical boosting Cf <1 means free radical removing

This correlation between N(photon) andN(FR) after application of the differentproducts is shown in Fig. 5. Differencesbetween the UVA-PF and the RSF can becaused, for instance, by free radical boost-ers and free radical protectors (19).Other reasons for differences betweenthe UVA-PF and the RSF are caused bythe testing procedure itself which iscaused by the generally known differ-ences between in vitro and ex vivo mea-surements such as:

1. Allocability of the product on skin orplate

2. Penetration of the product into thetest object (skin or plate)

3. Differences in reflection or absorptionof the radiation from the product andthe test object

4. Reactions between the product andthe test object (skin or plate)

5. Humidity of skin or plate

6. Differences in photostability of theUV-filters (skin or plate).

In spite of all these numerous influences,an adequate correlation is seen betweenthe two measured parameters UVA-PFand the RSF.Since the RSF method is based on the de-tection of all UV-induced free radicals inskin (from oxygen free radicals up to lipidperoxides), it is the shortest connectionbetween the cause (UV-radiation), thetransmitter (free radicals), and the con-sequence (skin damage). Thus, the RSF isan ideal parameter for the characteriza-tion of the efficacy of cosmetics to pro-tect skin against free radical injury.

Evolution of UVA/Free Radical Protection (Fig. 6)The four selected sunscreen samples inFig. 6 (No’s 15, 16, 05 and 12) demon-strate the evolution of UVA protectionover the last decades. 10 to 20 years agoUVB-only sunscreens were very common(Sample No 15). With the higher SPFsthis type of sunscreen disappeared. Onthe contrary day care products withoutphotostable UVA protection or none atall are still common because no regula-tion is in place. The UVA protection in Eu-rope is now also better than sample No 16(Fig. 6). Still higher UVA Protection asdemonstrated with sample No 12 is alsocommon. There is a perfect correlation(R = 1.0) among the three samples show-ing the possible progress.According to the US UVA-scale sampleNo 12 would fall into the »high« cate-gory (UVAI/UV = 0.93) just short of the

SOFW-Journal | 135 | 9-2009 11

COSMETICSUVA SUN PROTECT ION

Fig. 4 c RSF = 1.0 UVA-PF, but high variance with 7 samples of SPF > 20 (r=0.0)

Fig. 5 Correlation between the Quantity of photons N(Photons) and the quantityof generated free radicals N(FR)

»highest, 4 star rating« category. Withthe 4 star UVA category (UVAI/UV > 0.95)the proposed US-FDA rule [8] sets thehighest bar in the world regarding UVAprotection. To reach this »highest« 4 starrating a practically uniform UV protec-tion profile is required. This can only beachieved by a balanced combination ofUVB, UVA and broad-spectrum UV filters.It is especially not possible with an ex-cessive high UVB protection. Sunscreensor daily care products achieving the Eu-ropean UVA-recommendation will pro-vide a good balance between UVA/ FreeRadical Protection and SPF. Sunscreensor daily care products achieving aUVA/UVB ratio > 0.9 (5 BOOTS stars) or aUVAI/UV ratio > 0.95 (4 FDA stars) willachieve practically uniform Sun Protec-tion (e.g. No 12: SPF 20, UVAPF 16.3, RSF18.2).

� Conclusion

There is an urgent need to provide cos-metics with high UV protection over thewhole UVA and UVB range. Assessmentmethods are a crucial element in provid-ing good UV protection. Besides the con-ventional SPF (Sunburn Protection Fac-tor) UVA protection is critical. This studyshows that both the UVA-PF and the RSFprovide equivalent results regarding itsassessment. A similar assessment is pos-sible with in vitro »UVA/UVB« ratio meth-ods. The highest classifications in the UK(5 Boots stars) and the USA (proposed 4UVA stars) indicate practically uniform»UVA-UVB« protection and thus achievea similar protection factor against sun-burn, UVA damage and Free Radical for-mation. Such a protection factor couldbe referred to as a truly universal SkinProtection Factor (uSPF).

Not only sunscreens but also daily careproducts should offer an adequate andmodern concept of UV protection. There-fore it is crucial to apply the same as-sessment and categorization as it is nowdone for sunscreens.

AcknowledgementsThis work was partially financed by theEuropean Union (EFRE).

References

(1) Morganti P., Fabrizi G. New data on skin pho-toprotection. Int J Cosmet Sci. 22, pp 305-312(2000)

(2) Herrling T., Jung K., Fuchs J. UV – GeneratedFree Radicals (FR) in Skin and Hair – Their For-mation,Action, Elimination and Prevention. AGeneral View. SOFW-Journal 133, pp 2-11(2007)

12 SOFW-Journal | 135 | 9-2009

COSMETICSUVA SUN PROTECT ION

Fig. 6 Evolution of UVA Protection in Sunscreens of SPF 20

(3) Herrling T., Jung K., Fuchs J. Measurements ofUV-generated free radicals/reactive oxygenspecies (ROS) in skin. Spectrochim Acta A MolBiomol Spectrosc. 63 pp 840-5 (2006)

(4) AS/NZS (1998) Australian/New Zealand Stan-dard. AS/NZS, 2604

(5) Boots UK limited, Measurement of UVA/UVBRatios According to the Boots Star RatingSystem, 2008 revision, Nottingham, UK, Janu-ary 2008

(6) JCIA Measurement Standard for UVAUV-AProtection Efficacy. Japan Cosmetic IndustryAssociation – JCIA, 9-14, Toranomon 2-Chome,Minato-Ku Tokyo, p 105 (1995)

(7) European Commission Recommendation onthe efficacy of sunscreen products and theclaims made relating thereto, OJ L265,20067647/EC, 39 – 43

(8) Sunscreen Drug Products for Over-the-Counter Human Use; Proposed Amendmentof Final Monograph; Proposed Rule, FederalRegister=Vol. 72, No. 165/Monday, August27, 2007 49070-49122

(9) Osterwalder U.,Herzog B. Sun protection be-yond the Sun Protection Factor – New Effi-cient and Photostable UV-A Filters. SÖFW –Journal 127 pp 45 – 54 (2001)

(10) Osterwalder U., Herzog B. Vorbeugung gegenHautalterung und Hautkrebs – der lange Wegzurück zu einem ausgewogenen UV – Schutz.SOFW–Journal 134 pp 12-22 (2008)

(11) COLIPA UV-A guideline: Method for the invitro determination of UVA protection pro-vided by sunscreen products, 2007, The Euro-pean Cosmetic Toiletry and Perfumery Asso-ciation – COLIPA, Rue de la Loi 223/2, B-1040Bruxelles (www.colipa.com)

(12). Osterwalder U, Baschong W, Herzog B., BroadSpectrum UV protection and its assessment,Australian Society of Cosmetic Chemists, 39th

Annual Conference, Brisbane, Queensland, 17-20 March 2005

(13) Herzog B., Prediction of Sun Protection Fac-tors and UVA Parameters by Calculation of UVTransmissions Through Sunscreen Films of In-homogenous Surface Structure, Chapter 44in: Sunscreens: Regulations and CommercialDevelopment (3rd edition), Edited by N. Shaath.Cosmetic Science and Technology Series, Vol28; Taylor & Francis Group, Boca Raton, FL,2005, p. 881-900

(14) Ciba Homepage: www.ciba.com/sunscreen-simulator (accessed 16 June 2009)

(15) Herzog, B., Mongiat, S., Quass, K., Deshayes,C., Prediction of Sun Protection Factors andUVAUV-A Parameters by Using a CalibratedStep Film Model, J. Pharm. Sc. 93 (2004), 1780-1795

(16) Herrling T., Jung K.,Chatelain E., LangenauerM. Radical Skin/Sun Protection Factor RSF –Protection against UV-induced Free Radicals.SÖFW-Journal 132 pp 24-29 (2006)

(17) McKinlay, A.F. and Diffey, B.L., 1987. A refer-ence action spectrum for ultraviolet-inducederythema in human skin. CIE Journal, 6, 17-22, 1987

(18) Zastrow L., Groth L.N., Klein F., Kockott D., La-demann J., Renneberg R., Ferrero L., The Miss-ing Link - Light-Induced (280-1,600 nm) FreeRadical Formation in Human Skin, Skin Phar-macol Physiol 2009;22:31-44

(19) Jung K., Seifert M., Blume G., Herrling T. Thefatal effect of self-tanning agents during UVirradiation Part I. SÖFW-Journal 134 pp12-17(2008)

Authors’ addresses:* Uli Osterwalder

Ciba Inc. 4002 Basel

SwitzerlandEmail: uli.osterwalder@ciba.com

Ciba is now part of BASF

** Katinka JungMarietta SeifertThomas Herrling

Gematria Test Lab GmbHPestalozzistr. 5-8

13187 BerlinGermany

Email: email@gematria-test-lab.de

�

SOFW-Journal | 135 | 9-2009

COSMETICSUVA SUN PROTECT ION

Like silicon oil, only without silicon.

dermofeel®sensolv.

As is well known, the benefit of

silicon oils is only skin deep – the

feel might be incomparably soft,

but there is nothing natural about

the product. That’s why we have

developed dermofeel®sensolv,

which combines the soft-skin be-

nefits of silicon oils with the natural-

ness of sustainable ingredients.

dermofeel®sensolv is perfect as

a base oil for all kinds of skin care

products and due to its excellent

solvating properties it is a first

choice ingredient for sun care

and colour cosmetics. The result:

perfect sensory properties for your

cosmetic products that is appro-

ved by ECOCERT. Naturally.

intelligence behind beauty

www.dr-straetmans.de