Cited by 107Skin Protection and Agingmelanin and skin pigmentationContact Dermatitis and Allergies

Photostability of commercial sunscreens upon sun exposure and irradiation by ultraviolet lamps

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Gonzalez, Helena, Tarras-Wahlberg, Nils, Strömdahl, Birgitta, Juzeniene, Asta, Moan, Johan, Larkö, Olle, Rosén, Arne, Wennberg, Ann-Marie·2007·BMC Dermatology

Abstract

BACKGROUND: Sunscreens are being widely used to reduce exposure to harmful ultraviolet (UV) radiation. The fact that some sunscreens are photounstable has been known for many years. Since the UV-absorbing ingredients of sunscreens may be photounstable, especially in the long wavelength region, it is of great interest to determine their degradation during exposure to UV radiation. Our aim was to investigate the photostability of seven commercial sunscreen products after natural UV exposure (UVnat) and artificial UV exposure (UVart). METHODS: Seven commercial sunscreens were studied with absorption spectroscopy. Sunscreen product, 0.5 mg/cm2, was placed between plates of silica. The area under the curve (AUC) in the spectrum was calculated for UVA (320-400 nm), UVA1 (340-400 nm), UVA2 (320-340 nm) and UVB (290-320 nm) before (AUCbefore) and after (AUCafter) UVart (980 kJ/m2 UVA and 12 kJ/m2 of UVB) and before and after UVnat. If theAUC Index (AUCI), defined as AUCI = AUCafter/AUCbefore, was > 0.80, the sunscreen was considered photostable. RESULTS: Three sunscreens were unstable after 90 min of UVnat; in the UVA range the AUCI was between 0.41 and 0.76. In the UVB range one of these sunscreens was unstable with an AUCI of 0.75 after 90 min. Three sunscreens were photostable after 120 min of UVnat; in the UVA range the AUCI was between 0.85 and 0.99 and in the UVB range between 0.92 and 1.0. One sunscreen showed in the UVA range an AUCI of 0.87 after UVnat but an AUCI of 0.72 after UVart. Five of the sunscreens were stable in the UVB region. CONCLUSION: The present study shows that several sunscreens are photounstable in the UVA range after UVnat and UVart. There is a need for a standardized method to measure photostability, and the photostability should be marked on the sunscreen product.

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  • Combining avobenzone with other UV filters such as 4-MBC or octocrylene, or with bis-ethylhexyloxyphenol methoxyphenyl triazine, confers more stability to photounstable UV filters.

    “Moreover, the stabilisation of avobenzone (11) mediated by the combination with other UV filters, such methylbenzylidene camphor (7) or octocrylene (30) [48], or with bis-ethylhexyloxyphenol methoxyphenyl triazine (27) [35], was proved as an advantageous option that confers more stability to the photounstable UV filters.”

    From UV Filters: Challenges and Prospects (2022) · cites this paper as [48]

    The Discussion (page unavailable) acknowledges a reported stabilizing effect of 4-methylbenzylidene camphor on avobenzone, but says that effect did not appear in the sunscreen tested. The passages found do not establish stabilization by octocrylene. The triazine combination has a separate citation in the citing sentence, so it is not assessed against this source. (LLM, conf=0.88)

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Authors
Gonzalez, H., Tarras-Wahlberg, N., Strömdahl, B., Juzeniene, A., Moan, J., Larkö, O., Rosén, A., & Wennberg, A.-M.
Affiliations
  • Sahlgrenska University Hospital (SE)
  • University of Gothenburg (SE)
Corresponding author
Gonzalez, Helena
Venue
BMC Dermatology
Published
2007-02-26
Volume
7
Issue
1
Pages
1-1
ISSN
1471-5945 (ISSN-L)
OpenAlex
W2084447447
Cited by
107
References
25
Citations by year
2026: 5 · 2025: 8 · 2024: 4 · 2023: 9 · 2022: 5 · 2021: 7 · 2020: 9 · 2019: 6 · 2018: 8 · 2017: 2 · 2016: 8 · 2015: 3 · 2014: 7 · 2013: 5 · 2012: 5
FWCI
4.38
Type
journal article
Language
en
Open access
Locations
  • BMC Dermatology (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion)
  • NORA - Norwegian Open Research Archives (submittedVersion, cc-by)
Funders
  • Chalmers Tekniska Högskola
  • Vetenskapsrådet
Topics
  • Health Sciences › Medicine › Dermatology › Skin Protection and Aging
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › melanin and skin pigmentation
  • Health Sciences › Medicine › Dermatology › Contact Dermatitis and Allergies
Keywords
photodegradation, UVA, UV-B radiation, natural sunlight exposure
MeSH terms
Drug Stability, Spectrophotometry, Sunlight, Sunscreening Agents, Ultraviolet Rays, Area Under Curve

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