What determines skin sensitization potency–myths, maybes and realities. Part 1. The 500 molecular weight cut‐off. (25th August 2012)

• Record Type: Journal Article
• Authors: Roberts, David W.; Mekenyan, Ovanes G.; Dimitrov, Sabcho D.; Dimitrova, Gergana D.
• Is Part Of: Contact dermatitis. Volume 68:Number 1(2013:Jan.)
• Page Start: 32
• Page End: 41
• Publication Date: 2012-08-25
• Subjects: Contact dermatitis -- Periodicals; 616.51
• DOI: 10.1111/j.1600-0536.2012.02160.x
• Languages: English
• ISSNs: 0105-1873

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <bold>Background.</bold> It is widely accepted that there is a molecular weight (MW) cut‐off of 500, such that single chemicals with MWs higher than 500 cannot be skin sensitizers. If true, this could serve as a useful principle for designing non‐sensitizing chemicals.</p> <p> <bold>Objectives.</bold> To assess whether the 500 MW cut‐off is a myth or a reality.</p> <p> <bold>Methods.</bold> A database of 699 chemicals tested for skin sensitization in guinea pigs or mice was analysed to establish the number of tested chemicals with MW &gt; 500, and to establish whether any of these were sensitizers.</p> <p> <bold>Results.</bold> Only 13 (2%) of the 699 chemicals in the database have MW &gt; 500. Of the 13 tested compounds with MW &gt; 500 in the database, five are sensitizers and eight are non‐sensitizers.</p> <p> <bold>Conclusions.</bold> The 500 MW cut‐off for skin sensitization is a myth, probably derived from the widespread misconception that ability to efficiently penetrate the stratum corneum is a key determinant of sensitization potency. The scarcity of sensitizers with MW &gt; 500 simply reflects the general scarcity of chemicals with MW &gt; 500.</p> </abstract>