UV filters represent a new class of endocrine active chemicals. In vitro, 8/9 chemicals showed estrogenic (MCF-7 cells), and 2/9 antiandrogenic activity (MDA-kb2 cells). Six/nine filters (benzophenone (Bp)-1, Bp-2, Bp-3, 3-benzylidene camphor (3-BC), 4-methylbenzylidene camphor (4-MBC), octyl-methoxycinnamate (OMC)) increased uterine weight in immature rats. 3-Benzylidene camphor and 4-MBC displaced 16α I-estradiol from human estrogen receptor (ER)β , not ERα. Developmental toxicity of 4-MBC (0.7–47 mg/kg body weight/day) and 3-BC (0.24–7 mg/kg), administered in chow was investigated in Long Evans (LE) rats. Weight gain of pregnant rats was reduced only by 3-BC, early postnatal survival rate and thymus weight by both compounds at higher doses. 4-Methylbenzylidene camphor and 3-BC delayed male puberty, and dose-dependently affected reproductive organ weights of adult male and female F1 offspring, with partly different effect patterns. Thyroid weight was increased by higher 4-MBC doses. Tissue-specific changes in mRNA levels of estrogen-regulated genes in prostate, uterus and brain regions, determined by real-time PCR, and in their response to acute estradiol challenge in adult gonadectomized offspring were observed. Lowest effective doses were 0.24 mg/kg/day for 3-BC and 7 mg/kg/day for 4-MBC. Fat tissue levels at 7 mg/kg 4-MBC (GC–MS) approached the range of UV filters in fish (Nagtegaal et al., 1997; Balmer et al., 2004).
Currently used optical filters exhibit strong limitations in the deep UV and shorter wavelength ranges. We propose an entirely different type of UV filter to solve many of the problems due to inadequate materials and fabrication techniques. These filters consist of three-dimensionally ordered Macroporous Silicon (MPSi), with the pores used as waveguide cores separated by the reflective silicon host. Ordered pores serve as a two-dimensional array of optical waveguides. Multilayer coating of the pore walls results in the band-pass, short-pass, or band-blocking transmittance spectra of MPSi filters. Such filters have a number of advantages. They do not exhibit spectral shifts of the passed or blocked spectral bands with the angle of incidence, permitting operation in tilted and divergent light beams to simplify optical system design and fabrication. Due to their structures (fewer and thinner layers on the pore walls required to gain the same level of rejection), the filters do not exhibit delamination problems and are well suited for operation at extreme temperatures (for space as well as for terrestrial environments). The fabrication process is different from that used for multilayer interference filters. This process permits the fabrication of filters up to 200mm in diameter that are suitable for wavelengths from longer than 400 nm to shorter than 100 nm. Far-UV filters can be manufactured as simply and economically as the near UV ones. The theory of light propagation through the MPSi layers is developed, the main predictions of the theory are experimentally validated, and the fabrication procedure for MPSi UV filters is reported.
Two important ingredients of personal care products, namely polycyclic musk fragrances and UV filters, can be found in the environment and in humans. In previous studies, several compounds of both classes have been tested for their interaction with the estrogen receptor. Two polycyclic musk fragrances, namely AHTN and HHCB, turned out to be anti-estrogenic both in vitro and in vivo in a transgenic zebrafish assay. Several UV filters have been shown to exert estrogenic effects in vitro and in some in vivo studies. Here, we assessed the interaction of five polycyclic musk compounds and seven UV filters with the estrogen receptor (ER), androgen receptor (AR), and progesterone (PR) receptor, using sensitive and specific reporter gene cell lines. Four polycyclic musks (AHTN, HHCB, AETT, and AHMI) were found to be antagonists toward the ERbeta, AR and PR. The UV filters that showed estrogenic effects (benzophenone-3, Bp-3; 3-benzylidene camphor, 3-BC; homosalate, HMS; and 4-methylbenzylidene camphor, 4-MBC) were found to be antagonists toward the AR and PR. The ERalpha agonistic UV filter octyl-dimethyl-p-aminobenzoic acid (OD-PABA) did not show activity toward the AR and PR. Octyl methoxy cinnamate (OMC) showed weak ERalpha agonism, but potent PR antagonism. Butyl methoxydibenzoylmethane (B-MDM) only showed weak ERalpha agonism and weak AR antagonism. Most effects were observed at relatively high concentrations (above 1 muM); however, the anti-progestagenic effects of the polycyclic musks AHMI and AHTN were detected at concentrations as low as 0.01 muM. The activity of anti-progestagenic xenobiotics at low concentrations indicates the need to undertake more research to find out about the potential endocrine disrupting effects of these compounds in vivo.
Reversed-phase liquid chromatography (RP-LC) with UV detection was developed for the simultaneous determination of 16 organic UV filters worldwide authorised in suncare products. The filters determined were: 4-aminobenzoic acid, homosalate, benzophenone-3,2-phenylbenzimidazole-5-sulfonic acid, terephthalidene dicamphor sulfonic acid, 4- -butyl-4′-methoxy-dibenzoylmethane, octocrylene, 2-ethylhexyl-4-methoxycinnamate, isoamyl- -methoxycinnamate, ethylhexyltriazone, drometrizole trisiloxane, diethylhexyl butamido triazone, 3-(4-methylbenzyliden) camphor, 2-ethylhexylsalicylate, 2-ethylhexyl-4-dimethylaminobenzoate and benzophenone-4. A C stationary phase and a gradient of ethanol-aqueous acetate buffer containing 0.2 mM of EDTA, was used with a flow-rate of 1.0 ml/min. UV detection was carried out at 313 and 360 nm. The analysis required 32 min and the limits of detection were between 30 and 4130 mg/kg in the original suncare product. Tween 80 was used to break down the different emulsions in order to procure a proper extraction of the UV filters. The method was validated for UV filters in three matrices, oil, water-in-oil emulsion and oil-in-water emulsion. Recoveries from spiked samples were 86–113% depending on the matrix used.
An UVA and an UVB filter (4-tert-butyl-4'-methoxydibenzoylmethane and 3-(4-methylbenzylidene) camphor) insoluble inwater have been complexed with various cyclodextrins andβ-cyclodextrin derivatives. The molar ratio of theincluded UV filter to cyclodextrin in the solid complexeshave been calculated from thermal analysis data. Amongthe cyclodextrins studied randomly methylated β-cyclodextrinwas found to be the best solubilizer of both UV filters.The photostability of a model sulfonamide drug in aqueoussolution has been improved in the presence of a UVA filtersolubilised by RAMEB.