Commercial Sunscreen Research Articles

608 Development and assessment of nanoparticle-encapsulated sunscreens

The risk of developing skin cancer from ultraviolet radiation (UVR) can be mitigated with sunscreens. Safety and aesthetic concerns about commercial sunscreens have led to our development of a bioadhesive nanoparticle (BNP) sunscreen platform. Building upon prior work encapsulating FDA-approved agents avobenzone and octocrylene, we have now also encapsulated EU-approved agents diethylamino hydroxybenzoyl hexyl benzoate (DHHB) and octinoxate (OCX) with 50% and 30% loading, respectively. Nonadhesive nanoparticles (NNPs) are produced initially and can be converted to BNPs, which possess an aldehyde-rich corona that can bind epidermal amines.

Impact of Solvent Type on Total Phenol and Flavonoid Content and Sun Protection Factor of Crude Cashew Nutshell Liquid

Cashew nutshell liquid (CNSL) is a cheap source of natural phenolic compounds that have numerous applications. These phenolic compounds have chemical structures with chromophores similar to those found in synthetic chemical UV-filters, which are present in commercial sunscreen products (SSPs). Thus, this study investigated the impact of solvents on the yield, total phenol content (TPC), total flavonoid content (TFC), and the sun protection factor (SPF) of crude CNSL. The percent yield ranged from (30.4 ± 0.7% to 49.3 ± 3.2%); hexane recorded the lowest yield, while ethanol recorded the highest. Acetone (101.2 ± 2.5 mg GA/g), methanol (99.5 ± 0.10), and chloroform (95.4 ± 3.7 mg GAE/g), recorded the highest TPC respectively, while hexane (33.3 ± 0.7 mg QE/g) recorded the highest TFC. The SPFs ranged from (22.1 ± 1.1 to 16.4 ± 0.8), chloroform (22.1 ± 1.1), acetone (21.5 ± 1.1), and methanol (19.3 ± 1.0) again recorded the highest values respectively, while hexane (16.4 ± 0.8) recorded the lowest. Our results revealed that extracting solvents has a significant impact on the yield and SPF of CNSL. Therefore, we propose that acetone, chloroform, and methanol, either alone or as mixtures, could be the best solvents for extracting CNSL with a good TPC and SPF.

Dynamic visualization of ultraviolet dose on skin with sunscreen applied using minimum erythema dose.

Visualizing the ultraviolet (UV) dose on skin serve as an intuitive approach to ensure appropriate sunscreen usage and reduce the risk of erythema. UV dose is determined by a number of external factors, such as properties of sunscreens, weather, and type of outdoor activity. We propose a framework for visualizing UV doses that considers various external factors. First, the skin of a three-dimensional human model was represented using triangular meshes, and various static postures and dynamic motions were simulated to express outdoor activities. Then, we evaluated the persistency and insufficiency properties of sunscreen, which are time dependent and directly affect the effectiveness of the sunscreen skin protection factor (SPF) during UV exposure. Finally, to calculate the UV dose in real time, we tracked the trajectory of the sun and motion of the skin while considering the time-dependent properties of sunscreen. An S/W system was implemented based on the proposed framework to visualize the distribution of UV doses through dynamic color changes in exposed skin areas. The color types include true colors, which represent the minimum erythema dose (MED), and pseudo colors representing states before 1 MED is reached. We devised various examples to discuss the usability of the proposed framework. The system conveniently displays the MED according to an individual's skin phototype. When the properties of a wide range of commercial sunscreens are added to the system database, it is expected that the rate of appropriate sunscreen usage by customers will increase.

Exploring Plant-Based Cooking Oils as a Promising Topical Alternative to Sunscreen

Sunscreens protect the skin from the harmful effects of Ultraviolet radiation in the sunlight. However, most commercial sunscreens pose health and environmental hazards, lose effectivity over time, or are simply unpleasant to use, making it imperative to search for greener, safer, and efficacious alternatives. Plant-based oil extractions are promising given their hydrophobicity, nontoxicity, and availability. This paper aims to determine the absorptive capabilities of five common cooking (vegetable) oils using UVA spectrophotometry and analyze the properties of the oils that relate to their efficacy. Oils high in tocols, such as Rice Bran Oil, had the highest extinction coefficient. The analysis suggests that plant-based oil extractions high in phytonutrients with aromatic rings and pi-systems, such as tocols and carotenoids, present the greatest potential to serve as UV chemical filters.

Conversion of oxybenzone sunscreen to phototoxic glucoside conjugates by sea anemones and corals.

The reported toxicity of oxybenzone-based sunscreens to corals has raised concerns about the impacts of ecotourist-shed sunscreens on corals already weakened by global stressors. However, oxybenzone's toxicity mechanism(s) are not understood, hampering development of safer sunscreens. We found that oxybenzone caused high mortality of a sea anemone under simulated sunlight including ultraviolet (UV) radiation (290 to 370 nanometers). Although oxybenzone itself protected against UV-induced photo-oxidation, both the anemone and a mushroom coral formed oxybenzone-glucoside conjugates that were strong photo-oxidants. Algal symbionts sequestered these conjugates, and mortality correlated with conjugate concentrations in animal cytoplasm. Higher mortality in anemones that lacked symbionts suggests an enhanced risk from oxybenzone to corals bleached by rising temperatures. Because many commercial sunscreens contain structurally related chemicals, understanding metabolite phototoxicity should facilitate the development of coral-safe products.

The dynamic behaviour of sunscreens under in-service conditions.

Discussion continues over various aspects of sunscreen science: regulation, test methods, sun protection factor (SPF), labelling claims, potentially harmful components, among others. In this paper the UV transmission properties of a number of commercial sunscreens have been determined at constant sunscreen film thickness under different local UV Index conditions. The data demonstrate difficulties facing the public and the sunscreen industry as a whole, even though SPF values and other data stated on the sunscreen packaging are assumed to be correct according to standard testing methods. This work has shown that at realistic application rates the critical factors are the intensity of the incident solar radiation and the accumulated erythema UV dose transmitted over time. In one example, on 'Extreme' UV Index days, an SPF 30 sunscreen under test transmitted one minimal erythema dose (MED) of UV in only 35min. In another example, although it should not, in theory, transmit one MED until several hours of exposure, this level was reached in 1h by an SPF 50 sunscreen under these typical Australian summer conditions (UV Index 12) in Wollongong, NSW (34.4°S). Such properties could have severe consequnces if these sunscreens were used by individuals with Fitzpatrick Skin Type 1, organ transplant recipients or other immuno-compromised individuals.

In Vitro Testing of Sunscreens for Dermal Absorption: Method Comparison and Rank Order Correlation with In Vivo Absorption.

Evaluating the dermal absorption of sunscreen UV filters requires the development of a bio-predictable in vitro permeation test (IVPT). This work describes the comparison of two IVPT methods and rank order correlations of in vitro absorption (skin permeation and retention) with the in vivo absorption (AUC and skin retention) of sunscreens. The IVPT was compared regarding the following elements: (1) application of a single finite dose vs. an infinite dose and (2) the use of heat-separated human epidermis vs. dermatomed skin models. The IVPT was used to evaluate dermal absorption of six UV filters (avobenzone, homosalate, octinoxate, octisalate, octocrylene, and oxybenzone) in commercial sunscreens. Both the in vivo and in vitro permeation studies demonstrated that all UV filters were absorbed following a single-dose application. Sunscreens were rank ordered by the amount of the UV filters absorbed. Data obtained from the IVPT method using a single finite dose and heat-separated human epidermis was found to correlate with the clinical data. Rank orders of the cumulative in vitro skin permeation and the in vivo AUC were found comparable for oxybenzone, homosalate, octisalate, and octinoxate. Rank orders of the in vitro and in vivo skin retention of oxybenzone and octinoxate were also comparable. Additional IVPT parameters may be optimized to enhance the discriminatory power for UV filters with low skin permeation potential (e.g., avobenzone and octocrylene).

Ultrafast nonadiabatic mechanism of plant sunscreens biflavonoids with two excited-state intramolecular proton transfer structures

At present, the safety and environmental compatibility of commercial sunscreens are becoming unprotected. Most of the commercial sunscreens lack absorption and protection in high-energy UVA area. In this work, it has been proved that biflavonoids have sunscreen properties for the first time, especially, Amentoflavone (AME) covers almost the entire UV region and has high absorption. Different substituents have a great influence on the UV absorption of bisflavonoids. Therefore, we can adjust the substituents to obtain a broad protection region for sunscreens. Depending on the two-proton transfer donor and acceptor sites, it is theoretically proved that there is a reasonable competitive relationship between the two structures, and only one part of the proton transfer can be carried out in the molecule, which proved to be the proton donation of H1–O1–H2. When UV excited, biflavonoids will form intramolecular hydrogen bonds through proton transfer and emit energy in an ultra-fast pathway. Biflavonoid precursors could be used in sunscreen field and then the mechanism was proved, and it is a breakthrough in the research of expanding the field of plant filter. AME performs better than the current mature commercial sunscreens, and this work provided theoretical support to design a new biflavonoids for UV protection in future.

Sorption of Fulvic Acids onto Titanium Dioxide Nanoparticles Extracted from Commercial Sunscreens: ToF-SIMS and High-Dimensional Data Analysis

Titanium dioxide nanoparticles (n-TiO2) are common ingredients of sunscreens and are often released into surface waters during usage. Once released, the surface chemistry of n-TiO2 changes by interacting with dissolved organic matter (DOM). In previous studies, these interactions were investigated using model n-TiO2 and; therefore, do not account for the complex composition of the coating of n-TiO2 aged in sunscreens. Taking advantage of a mild extraction method to provide more realistic nanoparticles, we investigated the potentials of time of flight-secondary ion mass spectrometry (ToF-SIMS) combined with high-dimensional data analysis to characterize the sorption of fulvic acids, as a model for DOM, on titanium dioxide nanoparticles extracted from ten different commercial sunscreens (n-TiO2 ⸦ sunscreen). Clustering analysis confirmed the ability of ToF-SIMS to detect the sorption of fulvic acids. Moreover, a unique sorption pattern was recognized for each n-TiO2 ⸦ sunscreen, which implied different fractionation of fulvic acids based on the initial specifications of nanoparticles, e.g., size, coating, etc. Furthermore, random forest was used to extract the most important fragments for predicting the presence of fulvic acids on the surface of n-TiO2 ⸦ sunscreen. Finally, we evaluate the potential of ToF-SIMS for characterizing the sorption layer.

Zinc-metal\u2013organic frameworks with tunable UV diffuse-reflectance as sunscreens

BackgroundUV exposure continues to induce many health issues, though commercial sunscreens are available. Novel UV filters with high safety and efficacy are urgently needed. Metal–organic frameworks (MOFs) could be a suitable platform for UV filter development, due to their tunable optical, electrical, and photoelectric properties by precise controlled synthesis.ResultsHerein, four zinc-based MOFs with various bandgap energies were chose to investigate their optical behaviors and evaluate their possibility as sunscreens. Zeolitic imidazolate framework-8 (ZIF-8) was found to possess the highest and widest UV reflectance, thereby protecting against sunburn and DNA damage on mouse skin and even achieving a comparable or higher anti-UV efficacy relative to the commercially available UV filters, TiO2 or ZnO, on pig skin, a model that correlates well with human skin. Also, ZIF-8 exerted appealing characteristics for topical skin use with low radical production, low skin penetration, low toxicity, high transparency, and high stability.ConclusionThese results confirmed ZIF-8 could potentially be a safe and effective sunscreen surrogate for human, and MOFs could be a novel source to develop more effective and safe UV filters.Graphical

Fast and non-destructive neutron activation analysis for simultaneous determination of TiO2 and SiO2 in sunscreens with attention to regulatory and research issues

A new instrumental neutron activation analysis (INAA) for the simultaneous determination of titanium (TiO2) and silica (SiO2) dioxide as UV-filters in sunscreens is described. Samples are encapsulated, neutron irradiated (30 s) and after a suitable decay (3 min), the induced 51Ti (T1/2 = 5.76 min) and 29Al (T1/2 = 6.56 min) radionuclides are measured for the emitted γ-ray fingerprint. Three applications were carried out: (i) screening study (analysis of commercial sunscreens in combination with single particle inductively coupled plasma mass spectrometry (sp-ICP-MS); (ii) research study (development of innovative UV-filters such as titanium dioxide or bismuth titanate loaded inorganic mesoporous silica nanoparticles, MSN); (iii) validation study (intercalibration of a spectrochemical method – inductively coupled plasma optical emission spectrometry, ICP-OES). Collectively, the nuclear method appears a powerful tool adequate for quantifying TiO2 and SiO2 in the above studies. The limited accessibility at the nuclear reactor for neutron activation is probably one of the reasons why the excellent characteristics of the nuclear technique are not always fully known and exploited in the industrial and research chemical world.

Self-Assembly of Cellulose Nanocrystals and Organic Colored Pigments as Reinforcement Matrix of Lipstick for Enhancing SPF.

The vermilion of the human lip, covered by a skinny epithelium with little melanin, is quite susceptible to damage from ultraviolet (UV) radiation exposure. However, commercial sunscreen filters and indelible dyes used in lipsticks can cause health hazards after percutaneous absorption or accidentally oral administration. Inspired by plant pigmentation as natural filters to protect themselves against overexposure to UV, safer bio-based sunscreens of cellulose enveloped with anthocyanin (AN) were developed using bionic design. Cellulose nanocrystals (CNC), derived from acid hydrolysis of cellulose, reinforced enhancement of UV absorption and shielding properties of AN. This innovation addresses the issue that naturally sourced UV filter application to sunscreen does not achieve a desired sun protection factor (SPF) value because of the low specific extinction value (E1,1). We also stated that the diverse formula of anthocyanin sunscreen lipsticks with CNC exhibited 10 times more SPF value than AN alone. Furthermore, they possess competitive benefits such as pleasing texture, superior adhesion, impermeable, nonphototoxicity, ease of application, and removal. This work provides a promising proof-of-concept for studying the features of natural sunscreens in the design of simple, safe, efficient, and green sunscreens.

Xanthomonadin mediated synthesis of biocidal and photo-protective silver nanoparticles (XP-AgNPs)

Nanoparticles have drawn significant attention in recent years, owing to their unique electrical, optical, biocidal, and catalytic properties. The present study reports an environment friendly, green approach for silver nanoparticles (AgNPs) synthesis using bacterial yellow color pigment, xanthomonadin (XP) derived from Xanthomonas sp. After exposing the reaction mixture to sunlight, a visible colour shift and spectrophotometric measurement proved that nanosized silver particles (XP-AgNPs) were being synthesized by xanthomonadin. The size of XP–AgNPs was in the range between 30 and 100 nm, with the spherical shaped particles. The XP–AgNPs showed excellent biocidal activity against representative Gram positive and Gram negative organisms i.e. Staphylococcus aureus, B. subtilis and Pseudomonas aeruginosa, Escherichia coli. In addition, using standard assays, the photo-protecting/SPF enhancement of commercial sunscreens and DPPH radical scavenging activity of XP, and XP-AgNPs were evaluated. As a result, adding 4 % w/w xanthomonadin in commercial sunscreens have original SPFs 4 and 10 increases by 271 % and 85.2 %, respectively. XP and XP-AgNPs showed significant antioxidant activities with the IC50 values of 46.21 µg/mL and 21.62 µg/mL, respectively. In conclusion, xanthomonadin mediated silver nanomaterial with photo protecting, antioxidant and biocidal potential has been reported.

Separating and Purifying Mycosporine-Like Amino Acids from Cyanobacteria for Application in Commercial Sunscreen Formulations

Separating and Purifying Mycosporine-Like Amino Acids from Cyanobacteria for Application in Commercial Sunscreen Formulations

Poptical properties of a mucilage

Opuntia is a cactaceae widely known because of its nutritional properties. However, this distinguished plant has other benefits that may be used in non-conventional applications. The aim of this work is to investigate the optical properties of a mucilage to obtain a deeper and more detailed knowledge about possible non-alimentary applications of this organic material. In this work, we investigate some optical properties such as the absorbance and reflectance of a powdered mucilage in wavelengths ranging from 200 to 1300 nm. In addition, samples of commercial sunscreens were analyzed in the same band to compare their optical properties with those of the mucilage. We also discuss the feasibility of employing this mucilage as a unique active ingredient in organic sunscreens because of its optical characteristics. Finally, we comment on the limited usefulness of the sun protection factor as a measure of sunscreen's efficacy.

UV‐Shielding Performance and Color of Lignin and its Application to Sunscreen

AbstractThe balance between sunscreen performance and color is a main obstacle in the preparation of high‐quality lignin‐based sunscreens. In this study, five lignin samples (i.e., NaOH–L, EG–L, G–L, 1,3‐PDO–L, and 1,4‐BDO–L) are extracted from sugarcane bagasse by using five different solvent systems. The lignin extracted by organic solvents clearly shows light color and excellent UV‐shielding performance, and the 1,3‐PDO–L sample reveals the lowest total color difference (ΔE is 30.4) and highest sun protection factor (SPF 3.99) among the samples obtained. The SPF of commercial facial creams significantly increases after addition of 5 wt% lignin samples, and the colors of these creams are lighter than that of 10 wt% lignin‐modified cream samples. Moreover, the lignin‐modified creams exhibit excellent broad‐spectrum UV absorbency. The synergistic effects of lignin and the active substances of commercial sunscreen dramatically enhance the UV shielding effect of the commercial sunscreen. The aging test confirms that the lignin‐based sunscreens have good photostability. This study provides a reliable reference for the development of lignin‐based sunscreens and high‐value utilization of lignin.

Sunscreens effectiveness are not altered by concomitant use of moisturizing creams: An ultraviolet reflectance photography study.

Sunscreens are widely used to protect the skin against the harmful effects of solar radiation. It is not known whether solar protection factor of a sunscreen is altered by the concomitant use of other cosmetic products. The aim of this study was to analyze changes in the protective effect of different commercial and ISO standards sunscreens with high SPF applied shortly before and after application of non-sunscreens galenic formulas type moisturizing creams. ISO 24444:2019 standard sunscreens, which claimed SPF 16 and 63, as well as 4 different claimed SPF 50 and 50+ commercial sunscreens were prepared and applied in different sequential order to the back of 25 volunteers and compared with different commercial moisturizing formulas. Ultraviolet (UV) reflectance photography followed by image analysis was used to compare untreated skin and skin treated with moisturizing creams alone and combined with sunscreens. The UV reflectance analysis showed no significant changes of the skin color reflectance treated with moisturizing cream compared with untreated skin. Application of the sunscreen formulations were associated with a 35% - 70% decrease in color related to the in vivo expected SPF, indicating significant UV absorption for all sunscreen formulas. All standard and commercial sunscreens showed no significant differences in UV reflection color level when combined with the different moisturizing creams applied before or after the sunscreen. Effectiveness of low- and high-protection sunscreens were not altered by the concomitant use of a moisturizing creams applied shortly before and after the sunscreens.

Snail slime-based gold nanoparticles: An interesting potential ingredient in cosmetics as an antioxidant, sunscreen, and tyrosinase inhibitor

Due to their properties, snail slime-based products have been appreciated and used worldwide. So, as an alternative and innovative use of snail slime, it was adopted to induce gold nanoparticles' formation, conferring them interesting properties. By a simple, one-pot, and eco-friendly approach, 14±6nm wide hybrid gold nanoparticles, having an inorganic metallic core decorated by the slime's main components, were obtained. Among their several properties, their antioxidant and tyrosinase inhibition activity were investigated through the DPPH and ABTS and the tyrosinase assays, respectively. After assessing their non-cytotoxicity in our previous work, the results revealed positive responses, enabling their use as a potential novel multifunctional ingredient in cosmetics. Interestingly, the gold nanoparticle photostability, investigated by means of a solar simulator lamp, suggests using them in commercial cosmetic sunscreen products as a potential alternative to the commonly used inorganic sunscreen ingredients. The theoretical Sun Protection Factor was evaluated, obtaining values in the range 0-12. The proposed environmentally friendly and cost-effective protocol for nanoparticle synthesis, following the principles of Green Chemistry, opens a hugely attractive space toward the study of snail slime-based gold nanoparticles as a potential multipurpose platform in cosmetics.

Revealing the structure-activity relationship between lignin and anti-UV radiation

As a highly abundant natural and renewable aromatic polymer, lignin has been proven to be a good UV-absorber and natural broad-spectrum sun blocker. The structure-activity relationship of lignin under UV radiation remains unclear due to lignin’s complexity and heterogeneity. Here we report the structure influence of lignin on its anti-UV radiation properties of sun protection factor (SPF), UV absorbance, and antioxidant activity by using different lignin model compounds, including β–O–4, β–β, and β–5 dimers, etc., representing the structures of both native lignins and technical lignins. Meanwhile, UV protection properties of six lignin preparations, including cellulolytic enzyme lignin (CEL), organosolv lignin (OL), and kraft lignin (KL) of pinus kesiya and eucalyptus, were also evaluated for better comparison. SPF values of sunscreen preparations were increased but varied with the same addition of each single model compound into the pure cream or commercial sunscreen. In particular, the SPF value of the sunscreen has been greatly enhanced by the addition of a certain molar concentration of a single model compound (0.0558 mmol, around 2 wt%) into the low SPF commercial sunscreen, which was attributed to the synergistic effects of lignin models and inherent sunscreen agent. By comparing, lignin models containing β–O–4 linkage displayed the least desirable UV protection properties in this work, and side-chain difference, especially the existence of conjugate structure and carboxylic groups, would significantly impact the lignin model compounds’ UV performance. Additionally, the antioxidant activities and UV absorbance of different model compounds and lignin preparations are closely related to their structures. These insights revealed the structure-activity relationship of lignin under UV radiation and will provide a theoretical basis for optimizing lignins or lignin derivatives as the sun-screening agents in sunscreens.

Effectiveness of Frangipani Leaf Extract (Plumeria alba Linn.) as a UV Filter

UV filters are necessary since UV rays are harmful to human skin. UV filter compounds in commercial sunscreen products can cause adverse effects. Thus, natural UV filters containing flavonoids, e.g. Frangipani (Plumeria alba Linn.) leaves, are needed. This research examined the use of flavonoids from P. alba leaf as a UV filter with in vitro and in vivo. Maceration was performed with 70% ethyl alco-hol and liquid-liquid extraction for flavonoid purification. Parameters tested were total flavonoid compounds, SPF value, and clinical symptoms of the melanogenesis inhibition scoring. The purification result was 43.6%. The flavonoid concentration in pure extract (64.4 mg QE /g) was higher than crude extract (57.6 mg QE/g). The highest SPF value (33.88) was observed in pure extract at 1400 mg/mL, while the same concentration of crude extract resulted in a lower SPF value (33.06). Pearson correlation analysis (0.536) indicated a di-rectly proportional relationship between SPF value and extract concentration. In vivo analysis was performed by scoring between 0-4 following the severity of erythema. After 21 days of sunlight exposure, the worst erythema was found in the negative control group (score 1.292). The best result was found in the group treated with pure extract 1400 mg/ml (score 0.542).