CAS No. 131-57-7
Benzophenone-3 (2-hydroxy-4-methoxybenzophenone) occurs naturally in some flowering plants. It is commercially synthesized as a sunscreen for use in lotions, conditioners, and cosmetics. It is also used as a UV stabilizer in plastic surface coatings and polymers. Benzophenone-3 is a common ingredient in sun-blocking agents.
People may be exposed through dermal application of sunscreens and cosmetic products. Small amounts of benzophenone-3 can be absorbed through human skin and excreted in the urine, mostly as a glucuronidated conjugate (Gonzalez et al., 2006; Gustavsson et al., 2002; Janjua et al., 2004; Ye et al., 2005). After dermal application of a 4% lotion over the entire body daily for 5 days, one study found that 1.2-8.7% of the applied benzophenone-3 amount was recovered in the urine (Gonzalez et al., 2006).
Human health effects from benzphenone-3 at low environmental doses or at biomonitored levels from low environmental exposures are unknown. Following dermal application, some cases of photoallergy or allergy to benzophenone-3 have been reported. Male reproductive toxicity has been inconsistently reported in chronic high dose animal studies (Daston et al., 1993; French, 1992). Benzophenone-3 has weak estrogenic activity or weak anti-androgenic activity (French, 1992; Schlecht et al., 2004; Schlumpf et al., 2001; Schreurs et al., 2005). No human hormonal changes were observed during four days of application of 10% benzophenone-3 lotion (Janjua et al., 2004). Benzophenone-3 is not considered mutagenic (Robison et al., 1994). IARC and NTP have no ratings as to human carcinogenicity of benzophenone-3.
Urinary benzophenone-3 levels include both conjugated and unconjugated forms and reflect recent exposure to the chemical. The NHANES 2003-2004 levels of urinary benzophenone-3 have been described by Calafat et al. (2008). The analysis showed that female participants had slightly higher urinary levels than males, and that non-Hispanic whites were more likely than non-Hispanic blacks to have levels above the 95th percentile of the overall population. Higher urinary benzophenone-3 levels also are apparent in non-Hispanic whites and females in NHANES 2005-2010 (CDC, 2012). In a study of 90 U.S. females aged 6-8 years, the median urinary benzophenone-3 level of 14.7 µg/L was comparable to the median levels of children 6-11 years of age (15.8-18.7 µg/L) in the NHANES 2003-2010 subsamples (Calafat et al., 2008; CDC, 2012; Wolff et al., 2007). Total benzophenone-3 urinary concentrations were detectable in 90% of a small sample of adults in whom the values ranged up to 3000 µg/L (Ye et al., 2005). Following short-term application of 10% benzophenone-3 lotion, men and women had mean urinary levels of 140 and 60 µg/L, respectively (Janjua et al., 2004).
Finding a measurable amount of benzphenone-3 in urine does not mean that the levels of benzphenone-3 cause an adverse health effect. Biomonitoring studies on levels of benzphenone-3 provide physicians and public health officials with reference values so that they can determine whether people have been exposed to higher levels of benzphenone-3 than are found in the general population. Biomonitoring data can also help scientists plan and conduct research on exposure and health effects.
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