Preparation and Characterization of Organic/Inorganic Composite UV Filter Microcapsules by Sol-Gel Method

Octyl methoxycinnamate and butyl methoxydibenzoylmethane are organic UV filters with poor photostability and will become photoallergy or phototoxic substance when exposed to ultraviolet radiation. The organic UV filters coated by microcapsules can reduce the photodegradation and avoid direct contact with the skin. Through microencapsulation, the application of UV filters in cosmetics becomes more effective and safer. This study first used the sol-gel method to create organic/inorganic composite UV filter microcapsules. We used sodium alginate as a shell material of the microcapsule to encapsulate UV filters. CaCO3 and tetraethyl orthosilicate (TEOS) were used as cross-linking agents, and sorbitan monooleate (Span 80) and polyoxyethylenesorbitan monooleate (Tween 80) were used as emulsifiers in the interfacial polymerization method for preparation. The results indicated that the microcapsules with 3 g of CaCO3 cross-linking agents had a similar particle size and better entrapment efficiency. The average sizes were 61.0 ± 4.9 μm and 48.6 ± 4.7 μm, and entrapment efficiencies were 75.3 ± 1.9% and 74.8 ± 1.7% for octyl methoxycinnamate and butyl methoxydibenzoylmethane, respectively. Utilizing sodium alginate as a cross-linking agent is better than TEOS due to the higher calcium content. In vitro transdermal delivery analysis showed that the release rate became steady.

Toxic effects of UV filters from sunscreens on coral reefs revisited: regulatory aspects for “reef safe” products

Background Tropical coral reefs have been recognized for their significant ecological and economical value. However, increasing anthropogenic disturbances have led to progressively declining coral reef ecosystems on a global scale. More recently, several studies implicated UV filters used in sunscreen products to negatively affect corals and possibly contribute to regional trends in coral decline. Following a public debate, bans were implemented on several organic UV filters and sunscreen products in different locations including Hawaii, the U.S. Virgin Islands and Palau. This included banning the widely used oxybenzone and octinoxate, while promoting the use of inorganic filters such as zinc oxide even although their toxicity towards aquatic organisms had been documented previously. The bans of organic UV filters were based on preliminary scientific studies that showed several weaknesses as there is to this point no standardized testing scheme for scleractinian corals. Despite the lack of sound scientific proof, the latter controversial bans have already resulted in the emergence of a new sunscreen market for products claimed to be ‘reef safe’ (or similar). Thus, a market analysis of ‘reef safe’ sunscreen products was conducted to assess relevant environmental safety aspects of approved UV filters, especially for coral reefs. Further, a scientifically sound decision-making process in a regulatory context is proposed. Results Our market analysis revealed that about 80% of surveyed sunscreens contained inorganic UV filters and that there is a variety of unregulated claims being used in the marketing of ‘reef safe’ products with ‘reef friendly’ being the most frequently used term. Predominantly, four organic UV filters are used in ‘reef safe’ sunscreens in the absence of the banned filters oxybenzone and octinoxate. Analysis of safe threshold concentrations for marine water retrieved from existing REACH registration dossiers could currently also safeguard corals. Conclusion There is a substantial discrepancy of treatments of organic versus inorganic UV filters in politics as well as in the ‘reef safe’ sunscreen market, which to this point is not scientifically justified. Thus, a risk-based approach with equal consideration of organic and inorganic UV filters is recommended for future regulatory measures as well as a clear definition and regulation of the ‘reef safe’ terminology.

Removal of Organic UV Filters Using Enzymes in Spent Mushroom Composts from Fungicultures

Organic UV filters in sunscreen products are released to aquatic ecosystems through human recreational activities and urban wastewater treatment plant effluents. The biodegradation of three organic UV filters, 2-ethylhexyl salicylate (EHS), homosalate (HMS) and ethylhexyl methoxycinnamate (EHMC), which cannot be effectively removed by conventional wastewater treatment plants, was investigated in this study. Spent mushroom compost (SMC), a waste product of the mushroom industry, which contains white-rot fungus extracellular enzymes, was tested for its ability to remove the three organic UV filters. The results of batch experiments revealed that the SMC enzyme extract of Pleurotus djamor exhibited the highest ability for EHS and HMS removal. The results of bioreactor experiments indicated that direct application of SMCs may be a feasible solution to remove EHS and HMS from urban wastewater. The application of SMCs for the removal of organic UV filters can be developed into a green and sustainable technology.

Biodegradation of two organic UV-Filters by single bacteria strains

Organic UV-filters, including 4-hydroxybenzophenone (4-HBP) and 2,4-dihydroxybenzophenone (BP-1), are persistent emerging contaminants whose presence in the environment poses a threat to aquatic organisms due to their endocrine disruptor’s properties. For this reason, finding suitable technological processes for their safety and efficient removal from the environment represent a priority for the scientific community. To the author’s knowledge, until now, there are no studies reporting the biodegradation of 4-HBP and BP-1 by a single bacteria strain. In this paper, there were tested the 4-HBP and BP-1 biodegradation potential of two Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and two Gram-negative (Salmonella typhimurium and Serratia rubidae). The 4-HPB biodegradation process was observed only in the presence of Gram-negative bacterial strains. Thus, the biodegradation rates of 4-HBP reached up to 12.7% after 24h of incubation in presence of Salmonella thyphimurium and up to 24.0% after 24h of incubation with Serratia rubidae. Staphylococcus aureus was able to biodegrade 26.7% of BP-1, while Salmonella thiphymurium was able to biodegrade 14.7% of BP-1 after 24h of incubation. Their biodegradation products generated during the 4-HBP biodegradation process by Serratia rubidae were analyzed through LC-MS/MS analysis. The (bio)degradation products were benzophenone and a multi-hydroxylated derivative of 4-HBP and the degradation pathways were proposed. The data obtained in this study gave important information regarding the 4-HBP and BP-1 potential biodegradation by single bacterial strains.