GD — Society for Dermopharmacy

Issue 1 (2004)

Author's Report
A. Posselt, R. Daniels*
UVA-Protective Performance of Sun Protection Products:
Has there been a market shift?

Introduction

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Light protective products play a decisive role as concerns preservation of the skin’s health. Excessive sun exposition may cause serious skin damage. A first noticeable reaction is sunburn, representing basically a UVB-induced inflammation of the skin but also the formation of skin tumours or light dermatoses are in causal connection with UV light. Likewise premature skin ageing, the formation of wrinkles and atony of the skin’s connective tissue are advanced by the influence of light. Responsible for this phenomen is in the first place the long-wave UVA radiation. In order to prevent such damage there is a demand for ever more efficient sun protection products. The progression of the performance increase in the last years can be easily traced back by means of the light protection factors (SPF) reaching meanwhile values of beyond 30. The consumer behaviour has assimilated to this trend and the majority meanwhile uses products with light protection factors in the range of 10 to 12. The high light protective performance of modern products is provided by the combination of various organic UV filters among themselves as well as an addition of reflecting micro pigments. Whereas the entire UV-filter quantity is to be as low as possible and an adequate protection in the UVB and UVA range is to be strived for.

UVB protection is specified standardized worldwide as light protection factor (LF or SPF). The determination of the protection parameter is stipulated in many national standards, whereas the processes described only differ insignificantly from each other so that the sun protection factors are easily comparable. In Europe the provisions are carried out according to the COLIPA SPF Guideline [1] which came in force in 1994.

Most producers indicate the UVA protection at present in compliance with the defaults of the Australian standard [3]. The claims of this standard are met as soon as the sun protection product reduces the transmission in the area 320 – 360 nm by at least 90 percent. The Australian standard does not stipulate any further differentiation beyond 90 percent absorption. This implies that when adhering to the Australian standard an adequate UVA-protection is still ensured for products with low SPF, with rising SPF, however, the UVA-protection may stagnate at the identical level without infringing the standard; thus the UVA protection does not automatically rise in correlation with the UVB-protection.

In order to counteract this deficiency in the scope of a characterization of the UVA-protection, numerous national and international working groups are commissioned with the elaboration of a standardized measuring method. Far advanced are these endeavours in case of a new in vitro method by which the UVA protection performance can be quantified thus allowing a differentiated representation of the product performance [4]. For this purpose a sun protection product is evenly applied on a superficially roughened substrate and subsequently the transmission through the protective film measured. The assimilation of the data and SPF as well as a weighting with the UVA-relevant biological endpoint follow. The method can be easily performed in experiment and in the scope of a ring study by the DGK department “Lichtschutz” (Light Protection) a satisfactory reproducibility and robustness has been demonstrated [5]. These results correlate very well with in vivo data [6]. One year ago a first survey – based on this method – had been performed comprising 14 commercial products and the easy and exact applicability of this method could be confirmed. A definite differentiation of the products in view of their UVA-protective quality was feasible.

Since April 2004 the method has been published as DIN draft standard 67502 whereas the UVA-protection is now calculated as UVA-balance. This allows, based on the type of calculation, an even more pronounced differentiation of the UVA protective performance compared with the UVA-index earlier displayed. The present study is based on the new calculation method.

The objective of the current analyses on this methodical basis has been to reassess current commercial products in view of their UVA protective performance. Again sun protection products in the category SPF 10-12 have been tested in order to determine the evolution of the UVA-protection. Particular interest was focused on the fact whether or not the trend discovered one year ago is still valid. Accordingly, products with the highest UVA-protective performance were offered for sale in 2003 by producers who intensely deal with the topic sun protection in research and development. Whereas discount products could preponderantly be found in the group of products providing sparse protection.

Implementation

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19 sun protection products have been bought at discounters, the food trade and in pharmacies. The products contain different UV-filter systems with SPF 10-12. The majority of the products claims wide-band protection according to the Australian standard AS 2604 on the packing. Merely for two products the UVA-/UVB-long-term protection is displayed however without cross reference to the Australian standard. The data relating to the SPF, the product form as well as the UV-filters contained are listed in table 1.

Table 1: Overview of the sun protection products subject to the analysis
(Product; SPF; Product Form; Filter Composition)

Enlarged Version

Abbreviations:
BEMT= Bis-Ethylhexyloxyphenol Methoxyphenol Methoxyphenyl Triazine
BMDBM= Butyl Methoxydibenzoylmethane
DBT = Dietyhlhexyl Butamido Triazone
DTS = Drometrizole Trisiloxane
EHMC = Ethylhexyl Methoxycinnamate
EHT = Ethylhexyl Triazone
HD = Hydrodispersion
IMC = Isoamyl p-Methoxycinnamate
MBC = Methylbenzylidene Camphor
OC = Octocrylene
SPBS = Sodium Phenylbenzimidazole Sulfonate
TiO2 = Titanium Dioxide
TDSA = Terephthalidene Dicamphor Sulfonic Acid
ZnO = Zinc Oxide

First of all the products were applied in a quantity of 0.75 mg/cm² on a one-sided roughened PMMA plate and measured with a spectral photometer (LOT-ORIEL-INSTASPECII component appliance). Three plates were prepared for each product on which four individual measurements were performed. In case the absorption exceeded the level of 2, the process has been repeated with a correspondingly reduced application volume [7]. The UVA-protective performance has been calculated, as outlined in the new DIN-draft standard 67502, as UVA balance from the transmission data and by including the claimed SPF.

Result and Discussion

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DThe measuring method could be applied trouble-free to all products. The standard deviation of the individual measurements was in a very narrow sector (0.6 – 4.9 percent). As can be gathered from figure 1, the scale of the UVA-protective performance reaches – indicated as UVA balance – from 13 to 45. This allows a clear differentiation of the single products. The product performance varies even more distinctly than in the comparative study in 2003 [figure 2]. The most efficient UVA-protection has been almost 3.5 times higher than the one of the most inefficient product in this series. This major difference which became obvious by the new method is to be considered as consumer relevant since the UVA protection plays an increasingly essential role when selecting a product. According to the current product description this fact remains however completely concealed to the customer.

Figure 1: Comparison of the UVA-protective performance of different sun protection products

Enlarged Version

In order to provide a larger basis for the comparison of the two producer categories, the number of products which are sold by discounters and chemist’ shops as low-price private brand has been extended to altogether twelve specimens. It could be proven that all of them only provide UVA-protection in the lower sector. The difference to the products of research-active brand producers has even intensified compared with last year’s results. Figure 2 opposes the mean value of the established UVA- balance for both product groups. Accordingly, the traditional brands represent distinctly more effective products for the consumer. The UVA-protection is on average at approximately 75 percent (!!) above the protective performance of the low-price producers.

Figure 2: Comparison of the average UVA-protective performance of different producers

Enlarged Version

In nine cases the data from the years 2003 and 2004 could be directly compared Two products showed a significant increase of the UVA-protection, six sun protection products resulted in nearly the identical UVA-balance value and only one product was measured 14 percent lower. The comparison of both sample collectives from 2003 and 2004 shows on average virtually no difference. However, when considering both producer categories one significant difference reveals. The UVA-protection of branded products has considerably increased according to both studies whereas the discount products only exhibit a marginal increase (figure 3). Unfortunately, the changes – also improvements in the UVA-protection which were proven in the study are not obvious for laymen. Only a direct comparison of the ingredient list gave evidence of qualitative and/or quantitative changes of formulations; the latter recognizable by the changed sequence of ingredients.

Figure 3: Comparison of the determined area of the UVA protection in the course of a study in 2003 and the current study in the year 2004.

Enlarged Version

Summary

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The current assessment of the UVA protection by means of the UVA balance value has confirmed the result of the preceding year. Although there is growing knowledge of the jeopardy emanating from an excessive UVA-exposure there is solely a minor impact on the sun protection products marketed. Only products offered by research-active producers comply with the UVA- and UVB-protection claimed by many sides. This protection should go distinctly beyond the Australian standard for products with high SPF in the UVA area. In contrast, discount products feature clear deficiencies in this protective aspect although this is not reflected by the currently usual declaration. It can be assumed that this situation will only change in favour of the customer when the declaration will be effected in accordance with a generally accepted differentiated assessment method

References

Prof. Dr. Rolf Daniels has graduated from university in the department Pharmaceutical Technology. Before returning to university he was employed for two years in the pharmaceutical research department of a major pharmaceutical company. 1995 he obtained a professorship for pharmaceutical technology at the Institut für Pharmazeutische Technologie (Institute for Pharmaceutical Technology) of the Technical University Brunswick. His main research fields comprise surfactant-free emulsion systems, stability assessment of semisolid systems and the controlled release of active agents. He is head of the department Dermocosmetics of the Gesellschaft für Dermopharmazie (GD) since 1997.

Author’s address:

Prof. Dr. Rolf Daniels,
Institut für Pharmazeutische Technologie
Technische Universität Braunschweig
Mendelssohnstraße 1
D- 38106 Braunschweig

E-mail: r.daniels@tu-bs.de

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