Investigation on the Validity of in vitro Sun Protection Factor and Ultraviolet-A Protection Factor Evaluation Method for Sunscreen Samples.

Factors affecting the in vitro Sun Protection Factor (SPF) and Ultraviolet-A Protection Factor (UVA-PF) of sunscreens were analyzed for verifying the validity and reliability of the ISO24443 evaluation method. UV absorbance measurements by different spectrophotometers did not lead to the large difference in in vitro SPF/UVA-PF, although the UV absorbance determined by each spectrophotometer exhibited relatively large difference when it was larger than 2. On the other hand, relatively large difference was found in in vitro SPF/UVA-PF by utilizing European Cosmetic and Perfumery Association (Colipa) 1994 or UV-solar simulated radiation (UV-SSR) for the spectral irradiance. Appropriateness of employing the coefficient of adjustment for the determination of in vitro UVA-PF was also found to be reexamined.

New formulation technology to boost sun protection.

OBJECTIVE: As every skin type worldwide is concerned by photoprotection, with consumers preferring cosmetic elegant and efficient sunscreen products, we aim at developing the most performant and desirable sun care products. METHODS: We selected an interesting polymer, abbreviated AAHCP and designed scanning electron cryomicroscopy (cryoSEM), small angle and wide angle X-ray scattering and confocal laser scanning microscopy studies to understand its behaviour in solution and in simplex sun care formulations. This allowed us to develop innovative sunscreen formulation technology that was demonstrated by in vitro and in vivo photoprotection methods. Comprehensive photoprotection evaluations were made on the fully developed sun protection product. RESULTS: We observed the polymer oil structuring properties as well as its ability to form small and stable droplets in simplex emulsions. In vitro and in vivo sun protection factor (SPF) measurements demonstrated the sun protection boosting efficacy of AAHCP polymer in several emulsions or as a stand-alone emulsifier. This formulation technology also allowed to filtering system concentration optimization. Use-test performed on a fully developed AAHCP-based sunscreen validated its optimal performances as well as its ideal cosmetic features, with non-sticky, non-greasy perception and invisible skin result. CONCLUSION: For the first time, thanks to a new specific polymer creating a new type of emulsion, we succeed in reconciliate in a single sun care product maximal SPF efficacy, resistance to numerous stresses and optimal sensoriality.

OBJECTIF: Tous les types de peau du monde étant concernés par la photoprotection, avec des consommateurs qui préfèrent des produits solaires élégants et efficaces, nous nous sommes donné pour mission de développer les produits de protection solaire les plus performants et les plus agréables. MÉTHODES: Nous avons sélectionné un polymère intéressant, l'« AAHCP ¼ dans sa forme abrégée, et avons conçu les études de cryomicroscopie électronique à balayage (CryoSEM), de diffusion des rayons X et de microscopie confocale à balayage laser (Confocal Laser Scanning Microscopy) pour comprendre son comportement en solution et dans des formulations de protection solaire simples. Cela nous a permis de développer une technologie innovante de formulation de protection solaire, qui a été démontrée par des méthodes de photoprotection in vitro et in vivo. Le produit de protection solaire a fait l'objet d'évaluations exhaustives de la photoprotection à la fin de sa phase de développement. RÉSULTATS: Nous avons observé les propriétés de structuration de l'huile polymère, ainsi que sa capacité à former de petites gouttelettes stables dans les émulsions de simplex. Les mesures du facteur de protection solaire (sun protection factor, SPF) in vitro et in vivo ont montré que la présence du polymère AAHCP dans plusieurs émulsions ou comme émulsifiant autonome optimise le niveau de protection solaire obtenu. Cette technologie de formulation a également permis d'ajuster la concentration du système de filtration. Le test en conditions réelles d'utilisation effectué sur une protection solaire à base d'AAHCP à la fin de la phase de développement a permis de valider ses performances optimales, ainsi que ses caractéristiques cosmétiques idéales, avec une sensation non collante et non grasse, et un résultat invisible sur la peau. CONCLUSION: Pour la première fois, grâce à un nouveau polymère spécifique créant un nouveau type d'émulsion, nous avons réussi à développer un produit de protection solaire simple à l'efficacité SPF maximale, qui résiste à de nombreuses contraintes et possède une sensibilité optimale.

[Characterization of sun protection performance: Quo vadis?] / Charakterisierung von Sonnenschutzleistung: Quo vadis?

The task of the first sunscreens was to prevent the development of sunburn and, following the spirit of the 1950/1960s, to not impair the tanning of the skin. The need to quantify the protective performance soon arose. Originally with the help of natural-nowadays artificial-sunlight, a method was developed to determine a sun protection factor (SPF). It is formally defined as a ratio between minimum erythema-effective UV dose on sunscreen-protected skin and minimum erythema-effective UV dose on unprotected skin (ISO 24444:2019). Three observations question the suitability of the method. (1) Interlaboratory variability: Despite strict standardization, results of SPF determinations from different laboratories are subject to large variations. (2) Natural vs. artificial sunlight: The radiation spectrum of artificial sunlight differs from that of natural sunlight. SPFs determined with artificial sunlight (as depicted on all sunscreens currently on the market) are significantly too high compared to SPF determination with natural sunlight. (3) Erythema burden: When determining SPF, subjects are exposed to potentially harmful radiation. Against this background alternative methods-in vitro SPF, hybrid diffuse reflectance spectroscopy (HDRS) and in silico calculations-are presented. These have the potential to replace the current method. As an immediate measure, it is recommended to return to the comprehensible description of low, medium, high, and very high protection and in the future to take into account the spectrum of natural sunlight.

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.

New in vitro SPF Evaluation Method for Hydrophilic Sunscreen Samples.

A new method was developed for the in vitro sun protection factor (SPF) evaluation of sunscreen samples. A new type of substrate, a hydroxyalkyl cellulose-coated plate, was also prepared specifically for hydrophilic samples. This new substrate was required because hydrophilic samples would be unlikely to wet the surface of the standard cosmetic PMMA UV evaluation plate. A super-hydrophilic quartz plate was prepared by corona-discharge treatment before an aqueous solution of hydroxyalkyl cellulose was spread on it. A flat and uniform hydroxyalkyl cellulose film was subsequently formed through the evaporation of water. Special care was taken to inhibit the generation of spatial non-uniformity. Six hydrophilic sunscreen samples with in vivo SPF values of 56, 55, 52, 25, 15, and 4, were then applied to the prepared hydroxyalkyl cellulose-coated plate, as well as a super-hydrophilic quartz plate and a flat hydrophobic PMMA plate. The thicknesses of the applied layers were determined using a wheel-shaped wet film thickness gauge immediately after the application, and UV transmission was measured using an SPF analyzer. The value of in vitro SPF was calculated from the UV absorbance and the thickness of the layer. For two out of the six samples, PMMA plate could not be available, as the samples were unable to wet the PMMA surface. Relatively small differences were observed between the in vitro SPF values when the super-hydrophilic and hydroxyalkyl cellulose-coated plates were used. Samples exhibiting higher in vivo SPF were also associated with higher in vitro SPF values, although a linear relationship was not observed. In contrast to the super-hydrophilic plate whose half-life of the super-hydrophilicity is only approximately five days, the hydrophilicity of the hydroxyalkyl cellulose-coated plate scarcely varied during six months of storage. Finally, a simplified evaluation method was also proposed. The validity of the method was verified through a ring test where three researchers employed this method in different laboratories at three independent organizations.

Spectral Homeostasis - The Fundamental Requirement for an Ideal Sunscreen.

Sunscreen application to UV-exposed skin is promoted to prevent skin cancer and sun damage, within a comprehensive photoprotection strategy that also includes sun avoidance and wearing UV protective clothing. The benefits of sunscreen are verified in preventing sunburn but appear to be largely presumptive in skin cancer prevention. Contemporary science establishes UVA as a primary driver of melanoma and photoaging. Consequentially, the traditional UVB-skewed protection of sunscreens provides an intellectual and logical explanation for rising skin cancer rates and, in particular, their failure to protect against melanoma. Better protection could be achieved with more balanced UVB/UVA sunscreens, toward spectral homeostasis protection. Greater balanced protection has another advantage of attenuating fewer UVB rays, which aid synthesis of vitamin D and nitric oxide. Percutaneous absorption of Soluble Organic UV Filters leads to systemic exposure, which becomes the relevant safety consideration. It is minimized by selecting Insoluble UV Filters with low absorption potential from a molecular weight above 500 Da. The filters must also be very hydrophilic, very lipophilic, or consist of particles. The risk-benefit ratio is a medical imperative, more so for cosmetics or sunscreens, since in principle there should be no risk from their use. The production of ideal sunscreens that mimic the effective, balanced UVB/UVA attenuation of textiles and shade is now possible, while maintaining an acceptable therapeutic margin of safety in humans and a favorable ecologic profile. Sunscreens with a favorable risk-benefit ratio and good esthetic properties or other consumer-friendly attributes will improve compliance and may achieve substantial clinical benefits.

Performance Metrics of Sunscreen Formulations: In Vitro and In Vivo Techniques.

Effective skin protection of consumers by sunscreens can only be achieved when meaningful and reliable test methods are available to objectively measure the protection of sunscreen products. Quantitative, scientifically sound, and valid methods to detect UVB and UVA light protection as well as methods to assess sunscreen substantivity to water are required. Continuous improvement and, if necessary, extension of the test methods are important to provide optimum protection from harmful sun rays to the consumer. This work documents the historical background of the development of sunscreen test methods and provides the actual worldwide status of applied methods. Future developments and trends are discussed as far as they actually become apparent.

The Formula for Best Sunscreen Performance: Beer-Lambert's Law Under the Microscope.

Sunscreens used for the protection of human skin work by attenuating the potentially harmful solar UV radiation. In recent years, the quantitative understanding of this attenuating effect has grown tremendously, enabling model calculations of sunscreen performance. Such calculations are based on the simulation of the UV transmission of the sunscreen film applied on human skin. However, there are 2 prerequisites assumed to hold. The first prerequisite is the applicability of the Beer-Lambert law for sunscreen films, and the second is that the thickness variation of the sunscreen film can be described with a gamma distribution of film heights. There is strong evidence from recent experimental work that both assumptions are correct. For several applications, calculations of sunscreen performance have been shown to be useful, for instance, in the design of new sunscreen formulations aiming for a certain sun protection factor or other characteristics, prediction of pre-vitamin D production in the skin in the presence of sunscreen, in vitro measurement of water resistance, and assessment of the ecotoxicological profile of a sunscreen formulation or the influence of oil polarity on UV-filter absorbance and the consequence for sunscreen performance.

Natural and Simulated Solar Radiation.

The extra-terrestrial solar spectrum corresponds approximately to a black body of temperature about 5,800 K, with the ultraviolet region accounting for almost 8% of the total solar energy. Terrestrial solar spectral irradiance peaks at around 500 nm in the blue-green region, whereas the diffuse component peaks in the UVAI-blue region of the spectrum, with the infrared component comprising almost entirely direct radiation. Several factors impact on the magnitude and spectral profile of terrestrial solar spectral irradiance, and these include solar elevation, reflection from land and sea, air pollution, altitude above sea level and cloud cover. Measurements of erythemal UV from a number of ground-based networks around the world indicate an approximate 4-fold difference in ambient annual exposure between Australia and countries in northern Europe. In the absence of measured data, models to compute solar UV irradiance are a useful tool for studying the impact of variables on the UV climate. Simulated sources of sunlight based on a xenon arc lamp can be configured to give a close match to the spectral output of natural sunlight at wavelengths less than about 350 nm, and these are invaluable in the laboratory determination of sunscreen performance, notably the Sun Protection Factor (SPF). However, the divergence -between natural and simulated solar spectra at longer wavelengths may explain why SPFs measured in natural sunlight are less than those determined in the laboratory.

Assessment of Natural Sunlight Protection Provided by 10 High-SPF Broad-Spectrum Sunscreens and Sun-Protective Fabrics.

In 1978, the FDA Advisory Panel proposed both indoor and natural sunlight SPF testing methods but reverted to indoor testing only in 1993. Today's sunscreen sun protection and broad-spectrum claims are based on mandated clinical tests using solar simulators and in vitro spectrophotometers. This research evaluated the protection of 10 high-SPF (30-110), broad-spectrum sunscreen products, as well as 6 sun-protective fabrics against natural sunlight in Arequipa, Peru. Each of the 17 subjects was exposed to natural sunlight for 1 h and 59 min under clear skies, with temperatures and humidity similar to those in an indoor clinical laboratory. Test sites were photographed 16-24 h later. Four dermatologists evaluated the photographs for erythema and persistent pigment darkening (PPD). Perceptible sun-induced skin injury (sunburn and/or pigmentation) was detected at 97% of the sunscreen-protected scores. The most sun-sensitive subjects obtained the least erythema protection. The higher the SPF was, the higher the erythema protection, but the intensity of PPD was also higher. The 2 sunscreens using only FDA-approved sunscreen filters rated 30 SPF and 45+ SPF performed poorly: Eighty-one percent of the 136 scores were graded 1 minimal erythema dose or higher erythema, achieving, at a maximum, SPF of 5-7 in natural sunlight. Sun-protective fabrics tested provided excellent sun protection. The erythema and PPD observed through the sunscreens in less than 2 h are incongruous with the broad-spectrum, high-SPF sunscreen claims. Reapplying these sunscreens and staying in the sun longer, as stated on the product labels, would have subjected the subjects to even more UV exposure. High-SPF, broad-spectrum sunscreen claims based on indoor solar simulator testing do not agree with the natural sunlight protection test results.

HDRS - Hybrid Diffuse Reflectance Spectroscopy: Non-Erythemal In Vivo Driven SPF and UVA-PF Testing.

BACKGROUND/AIMS: In order to define a label SPF of topically applied sunscreens, in vivo test methods like ISO 24444, FDA Guideline, and the Australian Standard are used worldwide. The basis of all these methods is to induce an erythemal skin reaction by UV irradiation to find the level of MEDu and MEDp (Minimal Erythmal Dose unprotected and protected). In vitro methods replacing the human skin by any kind of nonhuman material are still not available. Thus, offering the new hybrid diffuse reflectance spectroscopy (HDRS) technique that can maintain an in vivo level for SPF testing while neglecting the UV-dose-related erythemal skin reaction is a perfect combination to take care of sun protection and any ethical concerns in SPF testing nowadays. METHODS: HDRS is a combination of in vivo diffuse reflectance spectroscopy measurements on the skin and in vitro transmission measurements of a sunscreen on a roughened polymethylmethacrylate plate. By this technique, the in vivo behavior of the investigated sunscreen on the skin is measured as well as the UVB absorption, which is still nonvisible in the reflectance technique. In order to establish an alternative method for in vivo SPF and UVA-PF testing, a huge number of sunscreens (250 samples) were measured by HDRS and compared with the worldwide accepted standards ISO 24444, ISO 24442, and ISO 24443. The variety of sunscreens measured reflect a wide range of different types of formulations as well as a wide range of SPFs (5-120) to validate this new alternative SPF testing procedure. RESULTS: Far-reaching statistical data analyses show an excellent link between the new nonerythemal-driven HDRS-SPF technique and ISO 24444 results. In the same way, HDRS-UVA-PF results can be correlated with UVA-PF values calculated from ISO 24442 as well as from ISO 24443. The importance of the inclusion of a spectral ratio of photodegradation is shown in the comparison of photostable and photounstable products. CONCLUSION: Owing to the elimination of any erythemal-relevant UVB and UVA doses, absolutely no skin reaction occurs during the HDRS experiment. Consequently, there is no need to define an MED anymore. For the first time, an alternative way to arriving at SPF and UVA-PF values is shown, without any ethical concerns of SPF testing in vivo and/or any restriction of SPF testing in vitro. Regardless of the type of formulation or the level of protection, an excellent correlation between SPFHDRSand SPF24444as for sunscreen labeling could be found. By this new alternative nonerythemal technique, not only SPF values can be measured but also UVA-PF values can be calculated with a linear correlation to ISO 24442 as well as to ISO 24443 from the same set of data. By this a robust alternative test method of SPF and UVA-PF values is described, taking into account the interaction of sunscreen formulation and skin.

Evaluating the Sun Protection Factor of Cosmetic Formulations Containing Afzelin.

Exposure to UV radiation damages the skin and increases the risk of skin cancer. Sunscreen is used to protect the skin from the harmful effects of UV radiation. However, the chemical UV filters used in sunscreen can show toxicity and cause allergic reactions. A safe sunscreen that includes a lower content of chemical UV filters and exerts an excellent effect on UV protection needs to be developed. The objective of this study was to investigate whether the addition of afzelin to sunscreen could improve the sun protection factor (SPF). A synergistic effect between afzelin and organic sunscreen agents including padimate O and oxybenzone was confirmed. Interestingly, 100% in vitro SPF-boosting was observed when afzelin (0.05%) was applied with a standard SPF formulation containing organic sunscreens while afzelin alone had no contribution to the SPF. In vivo SPF analysis of the standard SPF formulation showed an SPF value of 13.3 that increased to 20.1 when supplemented with afzelin (0.05%). Additionally, afzelin showed no skin irritation in a human trial. These results suggest that afzelin is useful as a natural additive in sunscreen formulations and provides an SPF-boosting effect. Afzelin supplementation to the formulation showed the potential to reduce the use of synthetic photoprotectors, which could minimize the risk of synthetic agent toxicity.

EBT3 Gafchromic® film as a new substrate for in vitro evaluation of sun protection factor.

There exist different methods for the determination of sun protection factor (SPF) values for sunscreens. We aimed to develop a new in vitro method using EBT3 Gafchromic® film as a substrate. The colour of EBT3 Gafchromic® film changes when exposed to UV light. Films were covered by sunscreen preparations of different SPF values ranging from 0 to 50. Uncovered and covered films were exposed to different solar light energies and their colour change was compared. Absorbance spectra of films was measured at 633 nm using a UV-VIS spectrophotometer apparatus. The colour of the film darkens when ultraviolet energy increases, which means that absorbance increases with exposure time. However, when films are covered by sunscreens, the colour change is less visible and the absorbance significantly decreases with increasing SPF value. There is a linear correlation between the absorbance of EBT3 Gafchromic® film and SPF value of sunscreens covering the film. Statistical analysis demonstrated that the SPF value of a sunscreen can be predicted using EBT3 Gafchromic® film as a substrate. This is the first report of an in vitro method based on colour change of a substrate which takes into consideration exposure time, and relates more closely to conditions of real-life. Based on these parameters, this is a reliable in vitro method for SPF testing.

Recent information on photoaging mechanisms and the preventive role of topical sunscreen products.

The main environmental element causing photoaging is ultraviolet (UV) light, and this involves an extrinsic mechanism of skin aging superimposed on an intrinsic process. Clinical (evident) characteristics of photoaging include the presence of deep wrinkles, deterioration of skin laxity, and hyperpigmentation. In the UV light spectrum, UVA and UVB radiation cause the most damage in photoaging. UVB light has shorter wavelengths and is mostly absorbed by the stratum corneum, causing erythema and changes in the epidermis, whereas UV rays with longer wavelengths (i.e., UVA) penetrate to the deepest layer of the skin (i.e., the dermis) and interact with DNA. As a result of UV radiation, chemical reactions in the skin produce reactive oxygen species (ROS), which cause protein denaturation, impairment of RNA and DNA synthesis, and damage to the skin structure. Using local sunscreen agents can not only prevent sunburn, but also help prevent photocarcinogenesis and photoaging. Therefore, many epidemiological studies have been conducted with results showing credible and positive evidence for the safety and efficacy of sunscreen to prevent photoaging and photocarcinogenesis.

Synthesis and Characterization of Nanostructured Lipid Nanocarriers for Enhanced Sun Protection Factor of Octyl p-methoxycinnamate.

Sunlight is important to health, but higher exposure to radiation causes early aging of the skin and skin damage that can lead to skin cancers. This study aimed at producing a stable octyl p-methoxycinnamate (OMC)-loaded nanostructured lipid carrier (NLC) sunscreen, which can help in the photoprotective effect. NLC was produced by emulsification-sonication method and these systems were composed of myristyl myristate (MM), caprylic capric triglyceride (CCT), Tween® 80 (TW), and soybean phosphatidylcholine (SP) and characterized by dynamic light scattering (DLS), zeta potential (ZP) measurement, atomic force microscopy (AFM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and in vitro release studies. Pre-formulation studies were performed changing TW concentrations and no differences were found at concentrations of 1.0 and 2.0%. Two selected formulations were designed and showed an average size of 91.5-131.7, polydispersity index > 0.2, and a negative value of ZP. AFM presented a sphere-like morphology and SEM showed ability to form a thin film. DSC exhibited that the incorporation of OMC promoted reduction of enthalpy due to formation of a more amorphous structure. Drug release shows up to 55.74% and 30.57%, and this difference could be related to the presence of SP in this formulation that promoted a more amorphous structure; the release mechanism study indicated Fickian diffusion and relaxation. Sun protection factor (SPF) evaluation was performed using NLC and presented values around 40, considerably higher than those observed in the literature. The developed formulations provide a beneficial alternative to conventional sunscreen formulations.

Fabrication of TiO2/Zn2TiO4/Ag nanocomposite for synergic effects of UV radiation protection and antibacterial activity in sunscreen.

A systematic and detailed study has been designed and conducted, taking into account some of the proposed benefits such as increased efficiency, transparency, unique texture, protection of active ingredient and higher consumer compliance of cosmetics containing nano-sized metal oxides. The objective of the present study was to develop novel sunscreen cream containing a TiO2/Zn2TiO4/Ag nanocomposite for enhanced UV radiation protection and antibacterial activity. In this study, TiO2/Zn2TiO4/Ag nanocomposite was prepared using sol-gel method and characterized by FESEM, EDX, XRD, TGA, UV-vis spectrophotometry, and FTIR techniques. Different sunscreen creams were formulated by incorporating the nanocomposite and TiO2 nanoparticles and the Sun Protection Factor (SPF) against ultraviolet radiation and antibacterial activity were examined. The antibacterial activity of synthesized TiO2/Zn2TiO4/Ag nanocomposite was investigated against gram positive (S. aureus) and gram negative (Escherichia coli). TiO2/Zn2TiO4/Ag nanocomposite has a higher protective factor compared to TiO2 nanoparticles. The results show that the average particle sizes of the synthesized nanoparticles are on a scale below 100 nm. The energy gap of the TiO2/Zn2TiO4/Ag nanocomposite was 3.01 eV which is close to the energy gap of the pure TiO2 nanoparticles. The nanocomposite presents higher UV absorption than the pure TiO2 nanoparticles. According to MIC test, minimum inhibitory concentration for this nanocomposite was 10 mg/ml. According to the MTT test, up to 0.3 µg/ml of this nanocomposite was found not to be susceptible to toxicity and almost 79.5 % of the cells exposed to nanoparticles had vital activities. In fact, TiO2/Zn2TiO4/Ag nanocomposite addition to cream was considered, not only to achieve the best protection over the whole UV range but also to take advantage of any synergistic effects of them in sunscreens.

An Experimental Investigation of Human Presence and Mobile Technologies on College Students' Sun Protection Intentions: Between-Subjects Study.

BACKGROUND: Health promotion and education programs are increasingly being adapted and developed for delivery through digital technologies. With this shift toward digital health approaches, it is important to identify design strategies in health education and promotion programs that enhance participant engagement and promote behavior change. OBJECTIVE: This study aimed to examine the impact of an experiment testing various mobile health (mHealth) skin cancer prevention messages on sun protection intentions and message perceptions among American college students. METHODS: A sample of 134 college students aged 18 years or older participated in a 2×2×2 between-subjects experimental study, designed to examine the individual and combinatory effects of multiple dimensions (human presence, screen size, and interactivity) of digital technologies. The primary study outcome was intention to use sun protection; secondary outcomes included attitudes toward the information, two dimensions of trust, and information processing. RESULTS: Generally, intention to use sun protection was positively associated with the presence of human characters in the health educational messages (P<.001), delivering educational health messages on a large screen (ie, iPad; P<.001), and higher interactivity (P<.001). Only human presence produced more favorable attitudes (P=.02). Affective trust was positively associated with human presence (P=.006) and large screen size (P<.001), whereas cognitive trust was positively associated with human presence (P<.001) and small screen size (P=.007). Moreover, large screen size led to more heuristic processing (P=.03), whereas small screen size led to more systematic processing (P=.04). CONCLUSIONS: This experimental study demonstrates that the impact of mHealth skin cancer prevention messages differs based on platform and delivery design features. Effects on behavioral intentions, attitudes, and trust were found for conditions with human presence, highlighting the importance of including this feature in mHealth programs. Results from this experimental study can be used to optimize the design of mHealth educational interventions that promote sun protection.

Using ordered mesoporous silica SBA-15 to limit cutaneous penetration and transdermal permeation of organic UV filters.

Avobenzone (AVO), oxybenzone (OXY), and octyl methoxycinnamate (OMC), are widely used UV filters. The aim of this study was to investigate the effect of incorporation in mesoporous silica (SBA-15) on their cutaneous deposition and permeation. Stick formulations containing "free" and "incorporated" UV filters (SF1 and SF2, respectively) were prepared and characterized with respect to their physicochemical, thermal, and functional properties. Cutaneous delivery experiments using porcine skin with quantification by UHPLC-MS/MS, demonstrated that skin deposition of AVO and OXY after application of SF2 for 6 and 12 h was significantly lower than that from SF1 at each time-point (Student t-test, p < 0.05): e.g. OXY permeation across the skin was 30-, 12- and 1.5-fold lower after 6, 12 and 24 h, respectively, following application of SF2. Cutaneous biodistribution profiles of AVO and OXY to 800 µm evidenced a significant decrease in the amounts in the viable epidermis and dermis. In contrast, deposition of the more lipophilic OMC was not significantly different (p ˃ 0.05). In vitro photoprotective efficacy results demonstrated that adsorption/entrapment of UV filters enhanced the sun protection factor by 94%. In conclusion, SBA-15, an innovative mesoporous material, increased photoprotection by UV filters while reducing their cutaneous penetration and transdermal permeation.