Jump to main content
Jump to site search

Issue 9, 2006
Previous Article Next Article

Interactions between different solar UVB/UVA filters contained in commercial suncreams and consequent loss of UV protection

Author affiliations

Abstract

A systematic investigation of two well-known and popular commercial suncreams reveals significant degradation when exposed to simulated UV sunlight at an irradiance corresponding to natural sunlight. We have examined the photochemistry of two widely used sunscreen active agents in pure solvents separately and together (in solution), and in neat form, as well as their photochemistry when present in the actual suncream emulsion (as thin films on a glass substrate) since their combination typically produces suncreams with high sun protection factors (SPF): (1a) octyl methoxycinnamate (OMC; octinoxate) and (2a) 4-tert-butyl-4′-methoxydibenzoylmethane (also known as avobenzone and Parsol 1789), present in the two suncream formulations in combination with others (one also contained TiO2). Intermediates and/or photoproducts were identified by UV/visible spectroscopy, HPLC and liquid chromatographic/mass spectral methods, and by both 1H and 13C-NMR techniques. Structural assignments of the substrates produced were aided by examining model systems {viz. ethyl cinnamate (1b) and dibenzoylmethane (2b)} of the two sunscreen active agents. Irradiation of the cinnamates and the diketones together led to a [2 + 2] photocycloaddition process yielding cinnamate dimers and cyclobutylketone photoadducts that subsequently fragmented into substituted oxopentanoates and oxobutanoates. Similar findings were observed when the two active agents were simultaneously present in the same suncream emulsion.

Graphical abstract: Interactions between different solar UVB/UVA filters contained in commercial suncreams and consequent loss of UV protection

Back to tab navigation

Publication details

The article was received on 17 May 2006, accepted on 18 Jul 2006 and first published on 03 Aug 2006


Article type: Paper
DOI: 10.1039/B606768A
Citation: Photochem. Photobiol. Sci., 2006,5, 835-843
  •   Request permissions

    Interactions between different solar UVB/UVA filters contained in commercial suncreams and consequent loss of UV protection

    D. Dondi, A. Albini and N. Serpone, Photochem. Photobiol. Sci., 2006, 5, 835
    DOI: 10.1039/B606768A

Search articles by author

Spotlight

Advertisements