Homosalate

Homosalate is an organic compound used in some sunscreens. It is made by the Fischer–Speier esterification of salicylic acid and 3,3,5-trimethylcyclohexanol, the latter being a hydrogenated derivative of isophorone. Contained in 45% of U.S. sunscreens, it is used as a chemical UV filter.[3] The salicylic acid portion of the molecule absorbs ultraviolet rays with a wavelength from 295 nm to 315 nm, protecting the skin from sun damage. The hydrophobic trimethyl cyclohexane functional group provides greasiness that prevents it from dissolving in water.

Homosalate[1]

Names
IUPAC name 3,3,5-Trimethylcyclohexyl 2-hydroxybenzoate
Other names Homosalate
Identifiers
CAS Number	118-56-9^Y
3D model (JSmol)	Interactive image
ChemSpider	8059^Y
ECHA InfoCard	100.003.874
KEGG	D04450^Y
PubChem CID	8362
UNII	V06SV4M95S^Y
CompTox Dashboard (EPA)	DTXSID1026241
InChI InChI=1S/C16H22O3/c1-11-8-12(10-16(2,3)9-11)19-15(18)13-6-4-5-7-14(13)17/h4-7,11-12,17H,8-10H2,1-3H3^Y Key: WSSJONWNBBTCMG-UHFFFAOYSA-N^Y InChI=1/C16H22O3/c1-11-8-12(10-16(2,3)9-11)19-15(18)13-6-4-5-7-14(13)17/h4-7,11-12,17H,8-10H2,1-3H3 Key: WSSJONWNBBTCMG-UHFFFAOYAJ
SMILES O=C(OC1CC(CC(C1)(C)C)C)c2ccccc2O
Properties
Chemical formula	C16H22O3
Molar mass	262.349 g·mol^−1
Density	1.05 g/cm^3 (20 °C)[2]
Melting point	< -20 °C[2]
Boiling point	181–185 °C (358–365 °F; 454–458 K)[2]
Solubility in water	0.4 mg/L
Hazards
Flash point	171 °C (340 °F; 444 K)[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is ^YN ?)
Infobox references

Safety

Similar to other UV filter compounds,[4] more homosalate is absorbed into the stratum corneum of the face (25% of applied dose) versus back of volunteers.[5] Homosalate has been identified as an antiandrogen in vitro,[6] as well as having estrogenic activity toward estrogen receptors α,[7] and general in vitro estrogenic activity.[8] Homosalate has been shown to be an antagonist toward androgen and estrogen receptors in vitro.[9] Some work has shown that organic UV filters in general can present concerns.[10]

No evidence of toxicity or side effects have been documented in vivo.

References

1. Homosalate, Merck Index, 11th Edition, 4660.
2. Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
3. Homosalate, ChemIDplus.
4. Rougier A, Dupuis D, Lotte C, Roguet R, Wester RC, Maibach HI (1986). "Regional variation in percutaneous absorption in man: measurement by the stripping method". Arch. Dermatol. Res. 278 (6): 465–469. doi:10.1007/bf00455165. PMID 3789805.
5. Benson HA, Sarveiya V, Risk S, Roberts MS (2005). "Influence of anatomical site and topical formulation on skin penetration of sunscreens". Ther Clin Risk Manag. 1 (3): 209–218. PMC 1661631. PMID 18360561.
6. Ma, R.; Cotton, B.; Lichtensteiger, W.; Schlumpf, M. (2003). "UV Filters with Antagonistic Action at Androgen Receptors in the MDA-kb2 Cell Transcriptional-Activation Assay". Toxicological Sciences. 74 (1): 43–50. doi:10.1093/toxsci/kfg102. PMID 12730620.
7. Gomez E, Pillon A, Fenet H, Rosain D, Duchesne MJ, Nicolas JC, Balaguer P, Casellas C (2005). "Estrogenic activity of cosmetic components in reporter cell lines: parabens, UV screens, and musks". J Toxicol Environ Health A. 68 (4): 239–251. doi:10.1080/15287390590895054. PMID 15799449.
8. Schlumpf M, Schmid P, Durrer S, Conscience M, Maerkel K, Henseler M, Gruetter M, Herzog I, Reolon S, Ceccatelli R, Faass O, Stutz E, Jarry H, Wuttke W, Lichtensteiger W (2004). "Endocrine activity and developmental toxicity of cosmetic UV filters--an update". Toxicology. 205 (1–2): 113–122. doi:10.1016/j.tox.2004.06.043. PMID 15458796.
9. Schreurs RH, Sonneveld E, Jansen JH, Seinen W, van der Burg B (February 2005). "Interaction of polycyclic musks and UV filters with the estrogen receptor (ER), androgen receptor (AR), and progesterone receptor (PR) in reporter gene bioassays". Toxicol. Sci. 83 (2): 264–272. doi:10.1093/toxsci/kfi035. PMID 15537743.
10. Klimova, et al. (2013). "Current problems in the use of organic UV filters to protect skin from excessive sun exposure" (PDF). Acta Chimica Slovaca. 6 (1): 82–88. doi:10.2478/acs-2013-0014.