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BACKGROUND: The purpose of the present study was to investigate the antioxidant and antimicrobial activities of a conventional preservative system containing desferrioxamine mesylate (DFO) and optimize the composition of the system through mathematical models. METHODS: Different combinations of ethylenediaminetetraacetic acid (EDTA), sodium metabisulfite (SM), DFO and methylparaben (MP) were prepared using factorial design of experiments. The systems were added to ascorbic acid (AA) solution and the AA content over time, at room temperature and at 40 °C was determined by volumetric assay. The systems were also evaluated for antioxidant activity by a fluorescence-based assay. Antimicrobial activity was assessed by microdilution technique and photometric detection against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus brasiliensis. A multi-criteria decision approach was adopted to optimize all responses by desirability functions. RESULTS: DFO did not extend the stability of AA over time, but displayed a better ability than EDTA to block the pro-oxidant activity of iron. DFO had a positive interaction with MP in microbial growth inhibition. The mathematical models showed adequate capacity to predict the responses. Statistical optimization aiming to meet the quality specifications of the ascorbic acid solution indicated that the presence of DFO in the composition allows to decrease the concentrations of EDTA, SM and MP. CONCLUSION: DFO was much more effective than EDTA in preventing iron-catalyzed oxidation. In addition, DFO improved the inhibitory response of most microorganisms tested. The Quality by Design concepts aided in predicting an optimized preservative system with reduced levels of conventional antioxidants and preservatives, suggesting DFO as a candidate for multifunctional excipient.

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It is challenging to disperse lipophilic substances in a validated cytotoxicity assay, especially for compounds with log Kow greater than or equal to 5 that may show false negative results. The purpose of this study was to explain the challenges in conducting a cytotoxicity validated test of lipophilic substances: Minthostachys setosa, Pimenta pseudocaryophyllus, and Drimysbrasiliensis essential oils. Additionally, we compared the equivalence of Neutral Red (NR) and 3- (4,5-dimethylthiazol-2-yl) -5- (3- carboxymethoxyphenyl) -2- (4-sulfophenyl) -2H -tetrazolium, inner salt (MTS) in detecting cell viability. The Hydrophile-Lipophile Balance (HLB) technique was used to evaluate the dispersion of essential oils and cytotoxicity in accordance to the guidelines of the OECD / GD 129 validated cytotoxicity assay. We compared the equivalence of vital dyes by TOST equivalence test. According to the results, we demonstrated the possibility of using other ways to disperse the lipophilic substances. Based on the HLB theory, we selected polysorbate 20 as the best solubilizing agent of the essential oils studied in D10 culture medium.

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The use of sunscreen products is widely promoted by schools, government agencies, and health-related organizations to minimize sunburn and skin damage. In this study, we developed stable solid lipid nanoparticles (SLNs) containing the chemical UV filter octyl methoxycinnamate (OMC). In parallel, we produced similar stable SLNs in which 20% of the OMC content was replaced by the botanical urucum oil. When these SLNs were applied to the skin of human volunteers, no changes in fluorescence lifetimes or redox ratios of the endogenous skin fluorophores were seen, suggesting that the formulations did not induce toxic responses in the skin. Ex vivo (skin diffusion) tests showed no significant penetration. In vitro studies showed that when 20% of the OMC was replaced by urucum oil, there was no reduction in skin protection factor (SPF), suggesting that a decrease in the amount of chemical filter may be a viable alternative for an effective sunscreen, in combination with an antioxidant-rich vegetable oil, such as urucum. There is a strong trend towards increasing safety of sun protection products through reduction in the use of chemical UV filters. This work supports this approach by producing formulations with lower concentrations of OMC, while maintaining the SPF. Further investigations of SPF in vivo are needed to assess the suitability of these formulations for human use.

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Iron acquisition by bacteria and fungi involves in several cases the promiscuous usage of siderophores. Thus, antibiotic resistance from these microorganisms can be circumvented through a strategy of loading toxic metals into siderophores (Trojan Horse Effect). Desferrioxamine (dfo) and its cell-permeant derivative desferrioxamine-caffeine (dfcaf) were complexed with aluminum or gallium for this purpose. The complexes Me(dfo) and Me(dfcaf) (Me=Al3+ and Ga3+) were synthesized and characterized by mass spectroscopy and cyclic voltammetry. Their relative stabilities were studied through competitive equilibria with fluorescent probes calcein, fluorescein-desferrioxamine and 8-hydroxyquinoline. Me(dfo) and Me(dfcaf) were consistently more toxic than free Me3+ against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, demonstrating the Trojan Horse Effect. Wide spectrum antimicrobial action can be obtained by loading non-essential or toxic metal ions to microbes via a convenient siderophore carrier.

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Multifunctional formulations are of great importance to ensure better skin protection from harm caused by ultraviolet radiation (UV). Despite the advantages of Quality by Design and Process Analytical Technology approaches to the development and optimization of new products, we found in the literature only a few studies concerning their applications in cosmetic product industry. Thus, in this research work, we applied the QbD and PAT approaches to the development of multifunctional sunscreens containing bemotrizinol, ethylhexyl triazone, and ferulic acid. In addition, UV transmittance method was applied to assess qualitative and quantitative critical quality attributes of sunscreens using chemometrics analyses. Linear discriminant analysis allowed classifying unknown formulations, which is useful for investigation of counterfeit and adulteration. Simultaneous quantification of ethylhexyl triazone, bemotrizinol, and ferulic acid presented at the formulations was performed using PLS regression. This design allowed us to verify the compounds in isolation and in combination and to prove that the antioxidant action of ferulic acid as well as the sunscreen actions, since the presence of this component increased 90% of antioxidant activity in vitro.

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ABSTRACT The chronological skin aging is a progressive and natural process with genetic and physiological changes. However, ultraviolet (UV) radiation may accelerate the oxidative stress, generating carcinogenesis and photoaging. Natural compounds and their applications are considered a trend in the cosmetic market. The protein-based film-forming compounds play an important role, once it collaborates for the better distribution of sunscreens on the skin. Here we investigated the in vitro photoprotective effectiveness of sunscreens containing the hydrolyzed collagen associated with UVA, UVB and/or inorganic filters. Sunscreens were developed with octocrylene (7.5%), butyl methoxydibenzoylmethane (avobenzone) (3.0%) and/or titanium dioxide (5.0%), associated or not with the hydrolyzed collagen (3.0%). In vitro photoprotective effectiveness was determined in a Labsphere(r) UV2000S by the establishment of the sun protection factor (SPF) and critical wavelength (nm) values. Physicochemical and organoleptic characteristics were also assayed. The hydrolyzed collagen subjectively improved the formulation sensory characteristics. However, this bioactive compound led to a decrease of the SPF values of the photoprotective formulations containing octocrylene alone and octocrylene + butyl methoxydibenzoylmethane + TiO2. This inadequate interaction may be considered during the development of new sunscreens intended to contain protein-based components.

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ABSTRACT Glutaraldehyde (GTA) has been extensively used as a gelatin crosslinking agent, however, new natural ones have been suggested as more biocompatible. Polyphenols are possible candidates and the flavonols, such as rutin (RUT), also exhibit potential synergism with sunscreens and antioxidant agents used in cosmetics. In this work, gelatin microspheres (M0) were obtained and crosslinked with GTA 10 mM (MG) or RUT 10 mM (MR), dissolved in acetone:NaOH 0,01M (70:30 v/v). MG exhibited crosslinking extent of 54.4%. Gelatin, M0, MG and MR did not elicit any signs of skin damage, regarding the formation of erythema, the barrier function disruption and negative interference in the stratum corneum hydration. Oily dispersions containing M0, MG or MR, isolated or combined with benzophenone-3 or octyl methoxycinnamate, suggested that the microspheres, at a 5.0% w/w, had no additional chemical or physical photoprotective effect in vitro. Crosslinking with RUT had occurred, but in a lower degree than GTA. Microspheres had not improved sun protection parameters, although, non-treated gelatin interfered positively with the SPF for both UV filters. The in vivo studies demonstrated that these materials had very good skin compatibility.

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ABSTRACT The physicochemical attributes of emulsified systems are influenced by the characteristics of their internal phase droplets (concentration, size and morphology), which can be modified not only by the formulation components, but also by the analytical methodology employed. Thus, the aim of this work involved the physicochemical characterization of cosmetic emulsions obtained from different surfactants, as well as the introduction of the optical coherence tomography (OCT) as the analytical technique employed for the morphological characterization and particle size determination of the formulations. Three emulsions were prepared, differing at the type and concentration of the surfactant used, and their droplet sizes were evaluated through optical microscopy, laser diffraction and OCT. The microscopic analysis and the laser diffraction techniques provided an average particle size minor than 6.0 µm, not detected by the OCT technique, which could identify only bigger particles of the emulsified systems' internal phase. The results testify that OCT was suitable for the morphological characterization of cosmetic emulsions; however, the technique needs to be improved to ensure a better sensitivity in the analysis of smaller particles.

RESUMO Os atributos físico-químicos de sistemas emulsionados são influenciados pelas características de suas gotículas de fase interna (concentração, tamanho e morfologia), as quais podem ser modificadas não apenas pelos componentes da formulação, mas também pela metodologia analítica empregada. Desta forma, o objetivo deste trabalho envolveu a caracterização físico-química de emulsões cosméticas obtidas a partir de diferentes tensoativos, bem como a introdução da tomografia de coerência óptica (OCT) como a técnica analítica utilizada para a caracterização morfológica e determinação do tamanho de partícula das formulações. Três emulsões foram preparadas, diferindo no tipo e concentração do tensoativo empregado, e seus tamanhos de gotícula foram avaliados por meio das técnicas de microscopia óptica, difração a laser e OCT. As técnicas de microscopia óptica e difração a laser forneceram tamanhos de partícula médios menores de 6.0 µm, não detectados pela técnica de OCT, que permitiu apenas a identificação de partículas maiores pertencentes à fase interna dos sistemas emulsionados. Os resultados reforçam a introdução da OCT como metodologia promissora para a caracterização morfológica de emulsões cosméticas; no entanto, a técnica requer aprimoramento para garantir maior sensibilidade na análise de partículas de menor tamanho.

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Senna species have been widely used by American, African and Indian ethic groups mainly in the treatment of feebleness, constipation, liver disorders and skin infections. Senna occidentalis (L.) Link is a perennial shrub native to South America and indigenous to tropical regions throughout the world. Current study evaluated the antimicrobial activity of aqueous and hydroalcoholic extracts from S. occidentalis prepared from different parts of the plant. Antimicrobial activity was assessed against standard pharmaceutical microorganisms by spectrophotometry and microdilution technique. Escherichia coli was sensitive only to compounds extracted from seeds which may be proteinaceous. A broader antimicrobial spectrum was demonstrated by the hydroalcoholic extract of seeds, mostly against Pseudomonas aeruginosa. The in vitro toxicity using mouse fibroblasts indicated that the extract might be a biocompatible ingredient for topical formulations, while the hydroalcoholic extract of aerial parts demonstrated to be potentially cytotoxic.

Espécies de Senna são amplamente utilizadas por tribos americanas, africanas e indianas, principalmente para tratar a fraqueza, a constipação, as desordens do fígado e também em preparações tópicas para infecções de pele. A Senna occidentalis (L.) Link é um arbusto perene nativo da América do Sul encontrado em regiões tropicais. Este trabalho avaliou a atividade antimicrobiana de extratos aquosos e hidroalcoólicos de diferentes partes da planta. A atividade antimicrobiana foi estabelecida frente aos microrganismos padrões farmacêuticos por espectrofotometria e técnica de microdiluição. A Escherichia coli apresentou sensibilidade apenas a componentes extraídos das sementes, os quais podem ser de natureza proteica. O espectro mais amplo de atividade antimicrobiana foi obtido com o extrato hidroalcoólico das sementes, principalmente contra Pseudomonas aeruginosa. A toxicidade in vitro utilizando fibroblastos de camundongo indicou que este extrato pode ser um ingrediente biocompatível para formulações de uso tópico. Já o extrato hidroalcoólico de partes aéreas demonstrou ser potencialmente citotóxico.

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With the aim of reducing system absorption and consequently, the side effects, and simultaneously select a penetration enhancing, three topical formulations with 0.5% ciclopirox olamine (CO) and 15% of propylene glycol (PG), ethoxydiglycol or oleic acid were developed and evaluated regarding the skin penetration and cutaneous retention of the drug using Franz diffusion cells. Release experiments were performed through synthetic membrane while dermatomed pig ear skin was used to evaluate CO skin penetration and skin retention. Retention studies were carried out applying tape stripping method and dosing CO in stratum corneum and in epidermis and dermis. A HPLC method was validated for quantifying CO. All formulations tested with synthetic membrane presented no retention of the drug. Permeation data suggested that there was no systemic absorption of ciclopirox olamine from the studied formulations, even when the skin penetration enhancers were applied. Higher concentrations of the drug were found in the stratum corneum (SC) and also in epidermis and dermis, for all of the developed formulations. The addition of enhancers improved the penetration and cutaneous retention of CO, and propylene glycol promoted higher concentrations in epidermis and dermis, probably because its cumulative effect on the skin and by an efficient solvent power.

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