Formulation of sunscreens with enhancement sun protection factor response based on solid lipid nanoparticles

Solid lipid nanoparticle (SLN) was regarded as new topical delivery systems for pharmaceutical and cosmetic active ingredients. The purpose of this study is to develop carrier systems for organic and inorganic sunscreens based on a matrix composed of carnauba wax and decyl oleate. Formulae (F1–F7) were prepared using butyl methoxydibenzoylmethane and octyl methoxycinnamate as organic components, and titanium dioxide (TiO₂) was used as inorganic component. Both types of sunscreens were incorporated into SLN formulations using classical method of preparation. To evaluate the effect of the pigments on the nanoparticles, particle size was measured using Mastersizer particle size analyser. UV‐protection abilities of formulations were investigated by the in vitro sun protection factor test (SPF). Further parameters determined were spreadability as well as viscosity. The rheological behaviour of the formulations was also carried out. From the plot of log of shear stress vs. log of shear rate, the slope of the plot representing flow index and ontology of the y‐intercept indicating consistency index was calculated. The formulae showed a flow index of 0.2074–0.4005 indicating pseudoplastic flow behaviour. Significant increases in SPF values up to about 50 were reported after the encapsulation by using organic and inorganic filters in Canada wax and decyl oleate. So, SLN could be appropriate vehicles to carry organic and inorganic sunscreens. The rational combination of cinnamates, titanium dioxide and Zinc oxide has shown a synergistic effect to improve the SPF of cosmetic preparations.     

Development of a water-resistant and detergent-washable powder coated with a stimuli-responsive polymer and its application to suncare products

IFSCC Magazines , 12 (2009) (1) 3–7
It is generally well known that the surface of an inorganic UV-protective powder used in a sunscreen formula is treated with a fatty acid or other hydrophobic chemicals to obtain a high water resistance. Due to the resulting strongly hydrophobic surface, the treatment has a clear drawback in that it allows the sunscreen to leave its base components on the skin after washing with regular soap. Therefore, in this study to develop an intelligent sunscreen formula that has a high water resistance and can be washed away easily with regular soap, we focused on a pH-responsive polymer as the surface-treatment agent for a UV-protective powder. Numerous experiments led to the synthesis of the 2-acrylamido-2-methyl-1-propanesulfonic acid/11-methacrylamidoundecanoic acid (AMPS/MAU) copolymer, which is hydrophobic in acidic to neutral solution and hydrophilic in basic solution. Titanium dioxide subjected to surface treatment was treated with the AMPS/MAU copolymer showed a high pH-responsiveness that was similar to that of the polymer. A W/O-type sunscreen containing the pH-responsive titanium dioxide showed a high water resistance as well as a high washability with regular soap.
Keywords:  Detergent-washable, pH-responsive polymer, pH-responsive powder, sun care product, water-resistant     

Identification and determination butylmethoxydibenzoylmethane in the presence benzophenone-3 and ethylhexylmethoxycinnamate in suncare preparation

The protection of sun radiation is a problem on global level for all living organisms on Earth. The need of people for the overexposure to the UV radiation led human population towards finding novel ways of protection of this kind of radiation, in form of cosmetic preparations applied on the skin. So far, the high values of protection factors of preparations and total block preparations with sun protection factor of 50+ were achieved. Physical and chemical filters which absorb radiation are constituents of these preparations. European Union has set regulations as which substances and in what amounts could be used as UV absorbers. American FDA (Food and Drug Administration) also gave its list of the most frequently used UV absorbers in the sunscreen products, as well as their declared concentrations. The most frequently used concentrations of UV filters in cosmetics is between 0.1% and 10%. Concentrations of UV filters in sunscreen products have to be monitored in order to ensure that they are not less from the declared levels, on which depends the efficacy and safety of the product.
Butyl methoxydibenzoylmethane (BMDM) is used as a UV-A filter in suncare products. Optimized high performance liquid chromatography method for BMDM determination in the presence of other UV filters in suncare preparations is presented in this paper. Determination was performed on C₈ reversed phase using UV detection at 357 nm and isocratic mobile phase of acetonitrile and 0.5% phosphoric acid (70 : 30 v/v). Proposed method has limit of detection of 0.058 μg mL⁻¹, limit of quantification 0.193 μg mL⁻¹ and linearity correlation coefficient of 0.9989. Commercially available products were analysed using the proposed method. All analysed samples complied with EU directives limit of BMDM content to no more than 5%.     

Analytical methods for SiO2 and other inorganic oxides in titanium dioxide or certain silicates for food additive specifications

An analytical method has been developed for the detection of SiO(2) and other oxides in titanium dioxide and certain silicates used in food additives using inductively coupled plasma (ICP) atomic emission spectrometry without hydrofluoric acid. SiO(2) and other oxides in titanium dioxide or certain silicates were resolved by alkali fusion with KOH and boric acid and then dissolved in dilute hydrochloric acid as a test solution for ICP. The recovery of SiO(2) and Al(2)O(3) added at 0.1 and 1.0%, respectively, in TiO(2) was 88-104%; coefficient of variation was <4%. The limit of determination of SiO(2) and Al(2)O(3) was about 0.08%, and the accuracy of the ICP method was better than that of the Joint FAO/WHO Expert Committee on Food Additives (JECFA) test method. The recovery of SiO(2) and other oxides in silicates was 95-107% with a coefficient of variation of <4%. Using energy dispersive X-ray fluorescence spectrometry (EDX) with fundamental parameter determination, the content of SiO(2) and other oxide in titanium dioxide and silicate showed good agreement with the ICP results. ICP with alkali fusion proved suitable as a test method for SiO(2), Al(2)O(3) and other oxides in titanium dioxide and certain silicates, and EDX proves useful for screening such impurities in titanium dioxide and componential analysis of certain silicates.     

Major and trace elements in milk and Halloumi cheese as markers for authentication of goat feeding regimes and geographical origin

Sixty samples of milk, Halloumi cheese and local grazing plants (i.e. shrubs) were collected over a year from dairy farms located on three different locations of Cyprus. Major and trace elements were quantified using inductively coupled plasma–atomic emission spectroscopy (ICP‐AES). Milk and Halloumi cheese produced in different geographical locations presented significant differences in the concentration of some of the elements analysed. Principal component analysis showed grouping of samples according to the region of production for both milk and cheese samples. These findings show that the assay of elements can provide useful fingerprints for the characterisation of dairy products.     

The state of nano-sized titanium dioxide (TiO2) may affect sunscreen performance

In the past several years, there has been a trend in the sunscreen/cosmetics industry to replace micron-sized titanium dioxide (TiO(2)) particles with nanoscale materials. The increased use of nanoscale TiO(2) has resulted in questions about these and other nanoproducts. This study examines the effects of using nanoscale TiO(2) on ultraviolet (UV) attenuation in simple to complex sunscreen formulations. UV light attenuation, product stability, and potential damage to the skin barrier were examined with both nanoscale and microscale TiO(2) particles. Results indicate that none of the formulations decreased the barrier function of the skin and the best UV attenuation occurs when the TiO(2) particles are stabilized with a coating and evenly distributed such as with non-agglomerated coated nanoscale materials. This indicates that nanoscale TiO(2) may have better efficacy while lacking toxicity.     

Simultaneous determination of some ultraviolet-absorbing chemicals in sunscreen cosmetics using a high-performance liquid chromatography method

A method of gradient elution high-performance liquid chromatography (HPLC) for simultaneous determination of 11 different ultraviolet-absorbing chemicals of phenylbenzlmldazole sulphonic acid, 4-aminobenzoic acid, benzophenone-4, benzophenone-3, isoamyl p-methoxycinnamate, 4-methylbenzylidene camphor, octocrylene, ethylhexyl methoxycinnamate, homosalate, ethylhexyl salicylate, methylene bis-benzotriazolyl tetramethylbutyl phenol was developed for the application to sunscreen cosmetic products. In this study, an Agilent SB-C18 analytical column (250 × 4.6 mm, 5 μm) was utilized and methanol, tetrahydrofuran and perchloric acid aqueous solution (0.2 mL HClO(4) + 300 mL H(2)O) were used for gradient elution at a total flow rate of 1.0 mL min(-1). The optimum conditions for 11 different ultraviolet-absorbing chemicals analyses were investigated. All calibration curves showed good linear regression with UV detection (311 nm) within test ranges. The correlation coefficients were better than 0.999 in all cases. The assay was simple, selective, convenient and reproducible and is suitable for the determination of ultraviolet-absorbing chemicals in commercial sunscreen cosmetic products. The use frequency of 11 different ultraviolet absorbents in 100 sunscreen cosmetics was investigated and statistically analysed. The ultraviolet absorbent of maximum use frequency was ethylhexyl methoxycinnamate.     

Analytical methods for SiO2 and other inorganic oxides in titanium dioxide or certain silicates for food additive specifications

An analytical method has been developed for the detection of SiO₂ and other oxides in titanium dioxide and certain silicates used in food additives using inductively coupled plasma (ICP) atomic emission spectrometry without hydrofluoric acid. SiO₂ and other oxides in titanium dioxide or certain silicates were resolved by alkali fusion with KOH and boric acid and then dissolved in dilute hydrochloric acid as a test solution for ICP. The recovery of SiO₂ and Al₂O₃ added at 0.1 and 1.0%, respectively, in TiO₂ was 88–104%; coefficient of variation was <4%. The limit of determination of SiO₂ and Al₂O₃ was about 0.08%, and the accuracy of the ICP method was better than that of the Joint FAO/WHO Expert Committee on Food Additives (JECFA) test method. The recovery of SiO₂ and other oxides in silicates was 95–107% with a coefficient of variation of <4%. Using energy dispersive X-ray fluorescence spectrometry (EDX) with fundamental parameter determination, the content of SiO₂ and other oxide in titanium dioxide and silicate showed good agreement with the ICP results. ICP with alkali fusion proved suitable as a test method for SiO₂, Al₂O₃ and other oxides in titanium dioxide and certain silicates, and EDX proves useful for screening such impurities in titanium dioxide and componential analysis of certain silicates.     

Adaptation of the protocol for determining in vitro the sun protection factor of anti-solar sticks

Apart from the protection offered by clothing, the application of sunscreen products suited to each type of skin constitutes one way for decreasing the frequency of skin cancers nowadays. After having adapted an in vitro method for determining the efficacy of sunscreens in emulsion form, we wished to transpose this technique by adapting it for the anti-solar sticks for the evaluation of sun protection factor (SPF) using a spectrophotometer equipped with an integrating sphere. To do this, we tested 14 products in the market as well as sticks that we ourselves fabricated in the laboratory. In a base common to all of these sticks, we added organic (13 filters tested) and inorganic (two filters tested, titanium dioxide and zinc oxide) to their maximum permitted concentration in the European Union. In parallel, emulsions containing the same filters at the same percentage of use were studied; to be in keeping with the results on the products packaging on the one hand, and with the results obtained for the emulsion form on the other hand, we were able to determine the optimal mass which needed to be placed on the support used the in vitro test to determine the SPF.     

Chemico-physical and functional properties of inorganic sunscreens in cosmetic products

This paper reports preliminary results of a study carried out on liquid crystal emulsions added to three different inorganic sunscreens: ultrafine zinc oxide, ultrafine titanium dioxide (inorganic-treated) and ultrafine titanium dioxide (organic-treated hydrophobically).
The aim of the work was to investigate the influence of chemico-physical properties of inorganic sunscreens on the microstructure of cosmetic emulsions. The study was carried out using three different techniques: rheological measurements performed in dynamic conditions, to study the homogeneity of samples and their structural features; dispersion of powders in emulsions by optical microscopy and SEM/EDX analysis; and functionality of emulsions by UV spectroscopy, with adhesive tape as substrate.
Results show that the different chemico-physical properties of the micropigments lead to different interactions with emulsion components; these interactions may affect the functionality and microstructure of the whole system, with loss of stability.     

Comparison of sun protection factors determined by an in vivo and different in vitro methodologies: a study with 58 different commercially available sunscreen products

An extensive study on the sun protection factors (SPF) of sun care products was carried out using the COLIPA (The European Cosmetic Toiletry and Perfumery Association) method, which relates to in vivo experiments. Furthermore, in vitro methods were tested with sunscreen formulations that were prepared as films on surface-roughened plates of polymethyl methacrylate (PMMA). One of the in vitro methods, i.e. using the sunscreen tester, has been recently developed, whereas the second has been defined by a pure spectroscopic approach, which is based on spectral transmission measurements of sunscreen films. Altogether 58 different sunscreen formulations, with manufacturer declared SPF values ranging from 4 to 60 and currently available on the European market, were investigated. The quality of correlations with results from the individual products based on the different in vitro methods versus the COLIPA values that were considered as generally accepted standard values was assessed. In this context, also variations because of sample preparation and spectral measurement were discussed. For sunscreen products with in vivo SPF values larger 25, the spectral transmittance within the UVA/UVB range is rapidly decreasing, which is experienced even for products with reduced amounts reaching 0.5 mg cm(-2) and still leading to unsatisfactory correlation of the spectroscopically derived SPF values versus the results from the alternative assays. Opposite to these small amounts, a sunscreen product spread of 2 mg cm(-2) is standard for the in vivo COLIPA method, whereas an area-normalized amount of 1 mg cm(-2) is currently routinely used for the sunscreen tester method. Furthermore, an overview of the individual product characteristics, such as their specific critical wavelengths and their UVA/UVB ratios is provided; both parameters can also be calculated from the spectral absorbances of the standardized sunscreen films.     

No. 4Vol. 42, No. 2, pp. 102–109, 2008A novel water-based sunscreen gel using a polymer – zinc oxide composite

Conventional sunscreen products generally must strike a compromise between efficacy and product feel; the hydrophobic ingredients that provide the sun protection generally impart an unpleasant, greasy feel and the greater the SPF rating, the worse the greasy feel. We tested an idea that a water-based sunscreen gel formulation containing inorganic UV absorbers would provide an effective way to address these problems. Our goal was to find a way to disperse inorganic sunscreen materials in water and to incorporate them into a water-based gel which would provide a more pleasant product feel. After extensive research we discovered a polymer-zinc oxide composite (P-ZnO) with high UV protective effect and high dispersibility in water. In dried powdered form, P-ZnO can be easily dispersed in water. P-ZnO makes it possible to formulate a gel-type sunscreen, which is not possible using commercially available inorganic powders. The composite size of P-ZnO is about 500 nm and its structure consists of a dense aggregate of nano-ZnO having a size distribution in the 5–10 nm range and amorphous layers of poly acrylic acid coating zinc oxide to control the particle growth, block surface activity and prevent aggregation. The water-based P-ZnO sunscreen gel offers UV protection comparable to conventional products in a delivery vehicle that is much more pleasant to use.     

Influence of different parameters on droplet size and size distribution of sprayable sunscreen emulsions with high concentration of UV-filters

The purpose of this study was to evaluate the possible influence of different formulation and technological parameters such as sunscreen type and concentration, viscosity, propellant gas, actuator and valve type on size and size distribution of droplets in emulsions of waterproof sunscreens conditioned in aerosol cans. Different kinds of emulsion, W/Si and W/O, were prepared with high concentrations of organic and inorganic UV-filters. These formulations were incorporated in aerosol cans with gas (a blend of butane, propane and isobutane). The size and size distribution of the droplets were analysed by laser diffraction using a Malvern Spraytec. The results showed that the sprayability of the formulation and the particle size characteristics of the emitted sprays are dependent on the physicochemical properties of the formulations. Sprayable waterproof sunscreen emulsions, with a high sun protection factor and negligible percentage of emitted droplets below 30 mum, were successfully developed by optimizing formulation parameters and using appropriate actuators and valves.     

In vitro evaluation of the cutaneous penetration of sprayable sunscreen emulsions with high concentrations of UV filters

The aim of this study was to evaluate the possible penetration through human skin of organic and inorganic filters contained in sunscreen emulsions packaged in aerosol cans, using an in vitro method. Experiments were carried out on two different types of emulsion: W/Si and W/O. This study was conducted using static diffusion cells (Franz cells). The determination of organic UV filters [Methylene Bis Benzotriazolyl Tetramethylbutylphenol (MBBT); Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (BEMT); Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB); Ethylhexyl Methoxycinnamate (EMC); and 2-Ethylhexyl Dimethyl PABA (ED-PABA)] was performed by High Performance Liquid Chromatography (HPLC). Therefore, it was important to develop a single analytical method for the quantification of the five organic filters with the aim of facilitating the experiment. The determination of inorganic filters [titanium dioxide (TiO₂) and zinc oxide (ZnO)] was performed using an emission spectrometric analysis method (ICP-OES). The HPLC and ICP-OES methods were validated. After a penetration test of 24 h duration, the results showed very low penetration only for two of the organic filters (maximum penetration of 1.21 μg cm⁻² h⁻¹ for EMC and 0.14 μg cm⁻² h⁻¹ for MBBT) and no penetration for the inorganic filters. Moreover, more than 50% of each sunscreen agent stayed on the surface on the skin. These results are consistent with those in the literature that presents similar experiments. This study showed that the sprayable sunscreen products developed, which contained high concentrations of UV filters, presented a low level of skin penetration.     

天然植物油在防晒化妆品中的功效研究进展

随着人们对防晒认知的提高,防晒化妆品的需求不断增加,市场发展迅速。天然植物油基化妆品绿色环保,使用安全,深受消费者青睐。我国植物资源丰富,部分植物油除不饱和脂肪酸外,还含有黄酮类、类胡萝卜素、维生素E等多种功能性化合物,具有抗氧化和防紫外线的作用。介绍了我国几种天然植物油(山茶油、牡丹籽油、橄榄油、辣木籽油、杏仁油、椰子油、乳木果油、猕猴桃籽油、酪梨油、葡萄籽油和紫苏籽油)抗氧化和防紫外线的功效及在防晒化妆品中的应用,以期为开发清爽高SPF值防晒化妆品提供参考。     

Discrimination of Boletaceae mushrooms based on data fusion of FT-IR and ICP–AES combined with SVM

In this study, the individual and data fusion of Fourier transform infrared (FT-IR) spectroscopy and inductively coupled plasma atomic emission spectrometry (ICP–AES) were used for the discrimination of five species of Boletaceae mushrooms with the aid of support vector machine (SVM). First, the original FT-IR spectra of 230 samples with different species were preprocessed and optimized by second derivative (2D), Savitzky–Golay filter (15:1) and standardized normal variate. Second, the datasets of FT-IR spectra and ICP–AES were integrated, and the low-level data fusion strategy was used to classify different species mushrooms. Third, the latent variables of elements concentration and FT-IR spectra were extracted by partial least square discriminant analysis and two datasets were fused into a new matrix. Finally, the classification models were established by SVM. Compared with single spectroscopic technique, the mid-level data fusion strategy can provide better result. Especially, the accuracy of correct classification of samples in calibration and test sets were 100.00% and 98.68%, respectively. The results demonstrated that the mid-level data fusion of FT-IR and ICP–AES can provide higher synergic effect for the discrimination of different species Boletaceae mushrooms, which could be benefited for the further authentication and quality control of edible mushrooms.     

Design and in vivo evaluation of ultrafine inorganic-oxide-containing-sunscreen formulations

Ultrafine titanium dioxide, zinc oxide, and a 1:1 mixture of ZnO/TiO2 were used as 5% dispersions in sunscreen formulae. Three different carrier bases were evaluated for their accelerated stability and rheological properties with and without metal oxides based on sodium lauryl sulphate/polysorbate 80, triethanolamine stearate, and cetyl trimethyl ammonium chloride. All three bases showed thixotropic behaviour. Addition of metal oxides only affected the magnitude of viscosity not the viscoelastic behaviour. The cationic emulsion base was found to be the most stable to incorporate the microfine metal oxides, the others' viscosity values showing a significant drop in storage. The in vivo sun protection factors were determined on the cationic based emulsions in four human subjects using an UV source covering both UVA-UVB regions. The mean sun protection factors were found to be 5.03, 4.03, and 4.8 for TiO2, ZnO, and 1:1 ZnO/TiO2 respectively for 4 mg.cm-2 applications, the differences not being significant.     

Toxicological and hygiene characterization of titanium dioxide nanoparticles introduced to the gastrointestinal tract of rats. Communication 1. Integral, biochemical and hematologic indices, small intestinal macromolecule absorption, DNA damage

Water suspensions of titanium dioxide nanoparticles were introduced intragastrically to growing male Wistar rats daily for 28 days. The data obtained revealed the presence of toxic risks related to said nanomaterials action and demonstrate the necessity of sanitary regulation of titanium dioxide nanoparticles used in food contact materials, cosmetics and other commodity.     

酪氨酸酶活性的抑制研究及皮肤美白化妆品的研制

研究探讨了皮肤黑色的成因和皮肤美白机理。通过测定常用的6种生物美白剂对酪氨酸酶活性的抑制率，初步建立美白剂效果的评价体系，实验还表明自制中草药萃取物美白效果明显，抑制率可达95％。同时，开发了3种美白、祛斑、防晒等功能的化妆品，市场潜力很大。     

微波消解-ICP／AES法测定染整助剂中8种重金属含量

采用微波消解-电感耦合等离子发射光谱（ICP—AES）法测定纺织染整助剂中砷（As）、镉（Cd）、钴（co）、铬（cr）、铜（Cu）、镍（Ni）、铅（Pb）、锑（Sb）的含量,介绍了微波消解样品的工作条件和ICP—AES工作参数的优化选择。该方法准确度、灵敏度和回收率高,相对标准偏差小于5％。结果表明：微波消解-ICP／AES法适用于纺织染整助剂中多种重金属元素的快速测定。