Propylparaben

A miniaturized monolith-MWCNTs-COOH multi-stir-rod microextractor device for trace parabens determination in cosmetic and personal care products.[Pubmed:29674065]

Talanta. 2018 Jul 1;184:429-436.

A portable and simple microextractor device was constructed by aligning six miniaturized multi-stir-rod microextractors. Each microextractor was prepared from rod-like multiwalled carbon nanotubes functionalized with a carboxylic group (MWCNTs-COOH) in composite monoliths that were bundled together and connected to a small DC motor. Using six of these microextractors, the device could extract six samples at the same time. A scanning electron microscope (SEM) showed the MWCNTs-COOH well distributed throughout the highly porous structure of the monolith-MWCNTs-COOH-stir-rod. This miniaturized multi-stir-rod microextractor device was used for the extraction of four parabens, methylparaben (MP), ethylparaben (EP), Propylparaben (PP) and butylparaben (BP). Under optimized conditions, good linearities were obtained in the concentration range of 1.0ngmL(-1) to 1.0microgmL(-1) for MP and EP and 2.0ngmL(-1) to 1.0microgmL(-1) for PP and BP. The limits of detection were low, 636.2+/-7.6pgmL(-1) for MP, 675.5+/-6.0pgmL(-1) for EP, 676.6+/-8.6pgmL(-1) for PP and 803.4+/-9.6pgmL(-1) for BP. The developed microextractor could be used up to 15 times (%RSDs from 1.5 to 5.2) and also provided good preparation reproducibility (%RSD from 1.3 to 5.8, n=6). The % RSDs of intra-day (n=6) and inter-day (n=6) precisions were obtained from 1.10-7.79 and 1.96-7.55, respectively. This developed device coupled with high performance liquid chromatography-diode array detector (HPLC-DAD) was applied for the extraction and preconcentration of four parabens in personal care products and cosmetics. The recoveries were studied by spiking the standard solution of parabens in real samples. Good recoveries were obtained in the range of 89.0+/-2.7 to 102.7+/-1.8% for MP, 88.09+/-6.4 to 102.5+/-1.0% for EP, 83.4+/-6.4 to 102.9+/-1.5% for PP and 83.5+/-3.6 to 102.3+/-2.0% for BP. This developed device might be easily applied for the extraction and preconcentration of other trace organic compounds in sample matrices.

Urinary concentrations of parabens and reproductive parameters in young men.[Pubmed:29179076]

Sci Total Environ. 2018 Apr 15;621:201-209.

Parabens are a group of alkyl esters of p-hydroxybenzoic acid that are commonly added to personal care products, cosmetics, pharmaceuticals and beverage and food processing as antimicrobial preservatives. Parabens have been reported to show estrogenic effects and affect male reproduction function in animal models, but human epidemiologic studies are still scarce. The objective of this study was to examine associations between urinary concentrations of parabens and semen quality and reproductive hormone levels. This was a cross-sectional study with 215 young university students (18-23years old) recruited between 2010 and 2011 in Southern Spain (Murcia Region). All men provided a urine, blood and semen sample on a single day. Urinary paraben concentrations (methylparaben, ethylparaben, Propylparaben and butylparaben) were measured by dispersive liquid-liquid microextraction and ultra-high performance liquid chromatography with tandem mass spectrometry detection. Semen quality was evaluated by measuring volume, sperm concentration, total sperm count (TSC), motility and morphology following WHO guidelines. Serum samples were analyzed for reproductive hormones, including follicle-stimulating hormone, luteinizing hormone, testosterone, inhibin B and estradiol using immunoassays. Associations between urinary concentrations of parabens and semen quality parameters and reproductive hormone levels were examined using linear regression, adjusting for potential covariates. Ninety-four percent of the men had detectable urinary concentrations of parabens. After taking into account important covariates, urinary concentrations of parabens or their molar sum were not significantly associated with any semen parameters or any of the reproductive hormone levels. Relative to men in the lowest quartile of sum of urinary paraben concentrations, the adjusted difference (95% CI) of TSC (millions) for men in the 2nd, 3rd, and 4th quartiles were 4.1% (-37.1;45.3), -1.6% (-41.9;38.8), and -9.8% (-52.5;32.8), respectively (P-trend=0.55). Our results suggest that, in young men, urinary parabens may not adversely impact reproductive function, but further research is warranted to confirm these findings in other male populations.

Safety assessment of propylparaben in juvenile rats.[Pubmed:29248488]

Regul Toxicol Pharmacol. 2018 Feb;92:370-381.

There are conflicting literature reports that parabens, useful antimicrobial additives in pharmaceuticals, may have estrogenic activity. We conducted a comprehensive study to determine whether Propylparaben (PP) administration to juvenile rats is associated with adverse effects on reproductive development and function. PP was administered orally once daily to groups of Crl:CD(SD) rats at doses of 0 (vehicle), 10, 100, or 1,000mg/kg on Postnatal Days (PNDs) 4-90. In-life observations, clinical pathology, reproductive organ weights and histopathology, landmarks of sexual maturation, estrous cyclicity and functional reproductive competence were assessed. A conventional uterotrophic assay was conducted separately using the same doses. Systemic exposures to PP and 3 metabolites were evaluated on PND 7, 21 and 83. These studies demonstrated that PP was well tolerated when administered from PND 4-90at all doses (AUC[0-T] on PND 83=69.9ng*h/mL). Para-hydroxybenzoic acid, a non-estrogenic compound, was the predominant metabolite contributing to 95% of the total exposure at 1,000mg/kg/day on PND 7. There was no evidence of estrogenic activity at any dose, and no effects on reproductive organs or function. The No-Observed-Adverse-Effect-Level (NOAEL) was 1,000mg/kg/day.

Survey of selected personal care products in surface water of coral reefs in Kenting National Park, Taiwan.[Pubmed:29710583]

Sci Total Environ. 2018 Sep 1;635:1302-1307.

Kenting National Park (KNP) located in the Hengchun Peninsula in southern Taiwan is a popular tourist spot, annually attracting millions of visitors, who engage in water sport and amusement activities. In this region, sewage is directly discharged into the marine environment. In this study, the concentrations of five organic UV filters [benzophenone (BP), 2,4-dihydroxy benzophenone (BP-1), 2-hydroxy-4-methoxy benzophenone (BP-3), 2,2'-dihydroxy-4-methoxy benzophenone (BP-8), and 4-methylbenzylidene camphor], five preservatives [methylparaben (MeP), ethylparaben, Propylparaben (PrP), butylparaben, and benzylparaben], one disinfectant [triclosan (TCS)], and twenty-four detergent derivatives [nonylphenol (NP), nonylphenol ethoxylates (NP2EO-NP12EO), octylphenol (OP) and octylphenol ethoxylates OP2EO-OP12EO] were detected in seawater and river water samples collected from eight beaches in KNP and two major river estuaries in the Hengchun Peninsula. BP-3 was detected at all sampling sites and was higher in concentration than the other organic UV filters. The highest concentration of BP-3 was 1233ng/L collected from Wanlitong Beach. MeP and PrP were the main preservative components in seawater. The highest total content of preservative agents was 164ng/L collected from Houwan Beach. Moreover, NP was detected at all sampling sites, with the highest concentration found at Sail Rock Beach (26.5ng/L). The highest concentration of OP was 113ng/L in the Boli River estuary. The widespread use of personal care products (PCPs) has resulted in the release of their major ingredients into natural ecosystems. Therefore, the potential long-term effects of multi-PCPs at low concentration exposure to on the coral reef ecosystem in KNP must be considered and monitored.

Biodegradation of four selected parabens with aerobic activated sludge and their transesterification product.[Pubmed:29529513]

Ecotoxicol Environ Saf. 2018 Jul 30;156:48-55.

Parabens are preservatives widely used in foodstuffs, cosmetics and pharmaceuticals, which have led to elevated paraben concentrations in wastewater and receiving waters. Laboratory-scale batch experiments were conducted to investigate the adsorption and degradation of parabens in an aerobic activated sludge system. Results show that biodegradation plays a key role in removing parabens from the aerobic system of wastewater treatment plants, while adsorption on the sludge is not significant. The effects of parent paraben concentration, concentration of mixed liquor suspended solids (MLSS), initial pH and temperature on degradation were investigated using kinetic models. The data shows that the degradation of parabens could be described by the first-order kinetic model with the rate constant ranging from 0.10 to 0.88h(-1) at 25 degrees C and pH 7.0. Paraben degradation can be enhanced by increasing the MLSS concentration and temperature, or by decreasing the parent paraben concentration. Furthermore, the pH of the incubation system should be lower than 8.0. The half-lives of the parabens were estimated to range between 0.79 and 6.9h, with methylparaben exhibiting the slowest degradation rate. During degradation in the present system, transesterification occurred, with methylparaben being the major transformation product in the incubation systems of ethylparaben, Propylparaben and butylparaben. These results were confirmed by mass spectrometry and aliphatic alcohol additive experiments. This is the first discovery of paraben transesterification in an activated sludge system, and it is associated with trace methanol in the system.