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The impact of natural sunlight exposure on the UVB-sun protection factor (UVB-SPF) and UVA protection factor (UVA-PF) of a UVA/UVB SPF 50 sunscreen.
J Drugs Dermatol. 2011 Feb; 10(2):150-5.JD

Abstract

OBJECTIVE

To compare the functional stability of Cetaphil UVA/UVB Defense SPF 50 as measured by its ultraviolet B sun protection factor (UVB-SPF) and ultraviolet A protection factor (UVA-PF) values following exposure to natural sunlight versus the UVB-SPF and UVA-PF values of unexposed product.

METHODS

These two randomized, controlled, evaluator-blinded, single-center trials were conducted according to the methods outlined in the 2007 Proposed Amendment to the Final Monograph, “Sunscreen Drug Products for Over-the-Counter Human Use.” Sunscreen samples were applied to glass plates and exposed to ultraviolet radiation in the form of natural sunlight in four minimal erythemal doses (MED) ranging from 2–6 MED (42–36 mJ/cm2). Three test sites were identified on the back of each study subject. Exposed sunscreen (one of four doses), unexposed sunscreen, and a UVB-SPF 15 control sunscreen were applied to the three test sites in a randomized fashion, followed by UV irradiation of incremental doses. Erythema and pigment darkening responses were assessed immediately following UV exposure and again 16–24 hours (erythema) or three to 24 hours (pigment darkening) after exposure. UVB-SPF and UVA-PF values were calculated for the exposed and unexposed samples.

RESULTS

The calculated UVB-SPF and UVA-PF values for all test samples (exposed and unexposed) were >50 and >9, respectively, which were greater than the stated UVB-SPF and UVA-PF values on the product label. No differences were observed between the exposed and unexposed samples in UVB-SPF or UVA-PF.

CONCLUSION

The UVA and UVB protection using standard evaluation techniques of Cetaphil UVA/UVB Defense SPF 50 remains stable despite exposure of the sunscreen to natural sunlight containing UVB ranging from 2–16 MED (41–336 mJ/cm2) and coexistent UVA.

Authors+Show Affiliations

Thomas J. Stephens & Associates, Inc., Carrollton, TX, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

21283919

Citation

Stephens, Thomas J., et al. "The Impact of Natural Sunlight Exposure On the UVB-sun Protection Factor (UVB-SPF) and UVA Protection Factor (UVA-PF) of a UVA/UVB SPF 50 Sunscreen." Journal of Drugs in Dermatology : JDD, vol. 10, no. 2, 2011, pp. 150-5.
Stephens TJ, Herndon JH, Colón LE, et al. The impact of natural sunlight exposure on the UVB-sun protection factor (UVB-SPF) and UVA protection factor (UVA-PF) of a UVA/UVB SPF 50 sunscreen. J Drugs Dermatol. 2011;10(2):150-5.
Stephens, T. J., Herndon, J. H., Colón, L. E., & Gottschalk, R. W. (2011). The impact of natural sunlight exposure on the UVB-sun protection factor (UVB-SPF) and UVA protection factor (UVA-PF) of a UVA/UVB SPF 50 sunscreen. Journal of Drugs in Dermatology : JDD, 10(2), 150-5.
Stephens TJ, et al. The Impact of Natural Sunlight Exposure On the UVB-sun Protection Factor (UVB-SPF) and UVA Protection Factor (UVA-PF) of a UVA/UVB SPF 50 Sunscreen. J Drugs Dermatol. 2011;10(2):150-5. PubMed PMID: 21283919.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The impact of natural sunlight exposure on the UVB-sun protection factor (UVB-SPF) and UVA protection factor (UVA-PF) of a UVA/UVB SPF 50 sunscreen. AU - Stephens,Thomas J, AU - Herndon,James H,Jr AU - Colón,Luz E, AU - Gottschalk,Ronald W, PY - 2011/2/2/entrez PY - 2011/2/2/pubmed PY - 2011/8/30/medline SP - 150 EP - 5 JF - Journal of drugs in dermatology : JDD JO - J Drugs Dermatol VL - 10 IS - 2 N2 - OBJECTIVE: To compare the functional stability of Cetaphil UVA/UVB Defense SPF 50 as measured by its ultraviolet B sun protection factor (UVB-SPF) and ultraviolet A protection factor (UVA-PF) values following exposure to natural sunlight versus the UVB-SPF and UVA-PF values of unexposed product. METHODS: These two randomized, controlled, evaluator-blinded, single-center trials were conducted according to the methods outlined in the 2007 Proposed Amendment to the Final Monograph, “Sunscreen Drug Products for Over-the-Counter Human Use.” Sunscreen samples were applied to glass plates and exposed to ultraviolet radiation in the form of natural sunlight in four minimal erythemal doses (MED) ranging from 2–6 MED (42–36 mJ/cm2). Three test sites were identified on the back of each study subject. Exposed sunscreen (one of four doses), unexposed sunscreen, and a UVB-SPF 15 control sunscreen were applied to the three test sites in a randomized fashion, followed by UV irradiation of incremental doses. Erythema and pigment darkening responses were assessed immediately following UV exposure and again 16–24 hours (erythema) or three to 24 hours (pigment darkening) after exposure. UVB-SPF and UVA-PF values were calculated for the exposed and unexposed samples. RESULTS: The calculated UVB-SPF and UVA-PF values for all test samples (exposed and unexposed) were >50 and >9, respectively, which were greater than the stated UVB-SPF and UVA-PF values on the product label. No differences were observed between the exposed and unexposed samples in UVB-SPF or UVA-PF. CONCLUSION: The UVA and UVB protection using standard evaluation techniques of Cetaphil UVA/UVB Defense SPF 50 remains stable despite exposure of the sunscreen to natural sunlight containing UVB ranging from 2–16 MED (41–336 mJ/cm2) and coexistent UVA. SN - 1545-9616 UR - https://www.unboundmedicine.com/medline/citation/21283919/The_impact_of_natural_sunlight_exposure_on_the_UVB_sun_protection_factor__UVB_SPF__and_UVA_protection_factor__UVA_PF__of_a_UVA/UVB_SPF_50_sunscreen_ L2 - https://medlineplus.gov/sunexposure.html DB - PRIME DP - Unbound Medicine ER -