Joana Portugal Mota

Cutaneous biocompatible rutin-loaded gelatin-based nanoparticles increase the SPF of the association of UVA and UVB filters

The encapsulation of natural ingredients, such as rutin, can offer improvements in sun protection effectiveness. This strategy can provide enhanced flavonoid content and produces an improved bioactive compound with new physical and functional characteristics. As an alternative to common synthetic-based sunscreens, rutin-entrapped gelatin nanoparticles (GNPs) were designed and associated with ethylhexyl dimethyl PABA (EHDP), ethylhexyl methoxycinnamate (EHMC) and methoxydibenzoylmethane (BMDBM) in sunscreen formulations. The purpose of this study was to develop rutin-loaded gelatin nanoparticles and characterize their physicochemical, thermal, functional and safety properties. Rutin-loaded gelatin nanoparticles increased antioxidant activity by 74% relative to free-rutin (FR) solution. Also, this new ingredient upgraded the Sun Protection Factor (SPF) by 48%, indicating its potential as a raw material for bioactive sunscreens. The safety profile indicated that GNPs and glutaraldehyde (GTA) decreased HaCaT cell viability in a concentration/time-dependent manner. However, both blank nanoparticles (B-NC) and rutin-loaded nanoparticles (R-NC) had good performance on skin compatibility tests. These results functionally characterized rutin-loaded nanoparticles as a safe SPF enhancer in sunscreens, especially in association with UV filters.

Functional photostability and cutaneous compatibility of bioactive UVA sun care products

Sunscreens are the most-established approach for photoprotection. The strategy of providing antioxidant properties to sun care products by addition of natural and potent anti-free radical compounds has led to the development of bioactive sunscreens, able to neutralize the harmful effects of ultraviolet (UV) radiation. UVA filters, such as benzophenone-3 (BP) and butyl methoxydibenzoylmethane (BMDBM), can exhibit photodegradation which limits the development of broad spectrum sunscreens. Previous research verified that rutin interacts with filters incorporated in sunscreens. In this work, we focused on the development and evaluation of the efficacy of the sunscreens containing either BP or BMDBM with and without rutin. The addition of rutin to the UVA filters afforded antioxidant properties to the formulations and they were considered safe for human use. Additionally, rutin in combination with either BP or BMDBM increased the antioxidant activity about 40 times when compared with the UVA filters alone. Remarkably, the addition of rutin 0.1% (w/w) to BP 6.0% (w/w) raised the SPF from 24.3±1.53 to 33.3±2.89. In conclusion, these findings demonstrated that the addition of rutin into sunscreens can markedly improve the antioxidant properties of the formulation as well as photostabilize some of the UVA filters.

Rutin increases critical wavelength of systems containing a single UV filter and with good skin compatibility

Ultraviolet (UV) radiation is responsible for sunburns, skin cancer, photoaging, and the production of reactive oxygen species (ROS). The awareness on preventing these deleterious effects made the use of anti‐UVB formulations an important part of population habits; however, despite the availability of several antioxidants capable of ROS scavenging, the pharmaceutical market lacks products associating UV filters with natural compounds of proven efficacy. Here, we investigated the effect of rutin, a flavonoid with antioxidant activity, associated with UVB filters in dermocosmetic preparations.

Choline- versus imidazole-based ionic liquids as functional ingredients in topical delivery systems: cytotoxicity, solubility, and skin permeation studies

Abstract Background: Poor drug solubility represents a problem for the development of topical formulations. Since ionic liquids (ILs) can be placed in either lipophilic or hydrophilic solutions, they may be advantageous vehicles in such delivery systems. Nonetheless, it is vital to determine their usefulness when used at concentrations were cell viability is maintained, which was considered herein. Method: Five different ILs were prepared—three imidazole-based ILs: [C2mim][Br], [C4mim][Br], and [C6mim][Br]; and two choline-based ILs: [Cho][Phe] and [Cho][Glu]. Their cytotoxicity in human keratinocytes (HaCat cells), their influence in drug solubility and in percutaneous permeation, using pig skin membranes, was evaluated. Results: Caffeine and salicylic acid were used as model actives. Choline-based ILs proved to be more suitable as functional ingredients, since they showed higher impact on drug solubility and a lower cytotoxicity. The major solubility enhancement was observed for caffeine and further solubility studies were carried out with this active in several concentrations of the choline-based ILs (0.1; 0.2; 0.5; 1.0; 3.0 and 5.0%, w/w) at 25 °C and 32 °C. Solubility was greatly influenced by concentrations up to 0.5%. The choline-based ILs showed no significant impact on the skin permeation, for both actives. The size of the imidazole-based ILs alkyl chain enhances the caffeine solubility and permeation, but also the ILs cytotoxicity. Stable O/W emulsions and gels were prepared containing the less toxic choline-based ILs and caffeine. Conclusions: Our results indicate that the choline-based ILs were effective functional ingredients, since, when used at nontoxic concentrations, they allowed a higher drug loading, while maintaining the stability of the formulations.

An emerging integration between ionic liquids and nanotechnology: general uses and future prospects in drug delivery

There is a growing need to develop drug-delivery systems that overcome drawbacks such as poor drug solubility/loading/release, systemic side effects and limited stability. Ionic liquids (ILs) offer many advantages and their tailoring represents a valuable tuning tool. Nano-based systems are also prized materials that prevent drug degradation, enhance their transport/distribution and extend their release. Consequently, structures containing ILs and nanoparticles (NPs) have been developed to attain synergistic effects. This overview on the properties of ILs, NPs and of their combined structures, reveals the recent advances in these areas through a review of pertinent literature. The IL-NP structures present enhanced properties and the subsequent performance upgrade proves to be useful in drug delivery, although much is yet to be done.

Synthesis of benzoazole ionic liquids and evaluation of their antimicrobial activity: Síntese de líquidos iónicos derivados de benzoazóis e avaliação da sua atividade antimicrobiana

A new class of chemicals composed not of molecules but ions, an organic cation and an organic or inorganic anion, has recently attracted attention. When these new kind of salts are in the liquid state below 100 oC, they are named ionic liquids (ILs). In this work, the synthesis of ionic liquids obtained from a 2-mercaptobenzimidazole, 2-mercaptobenzoxazole or 2-mercaptobenzothiazole anion and 1-alkyl-3-methylimidazolium or choline cation are described. The antimicrobial activity against several Gram-positive and Gram-negative bacteria and a yeast was also evaluated.

Extraction Optimization and Structural and Thermal Characterization of the Antimicrobial Abietane 7α-Acetoxy-6β-hydroxyroyleanone

The abietane 7α-acetoxy-6β-hydroxyroyleanone (AHR), obtained from plant extracts, is an attractive lead for drug development, given its known antimicrobial properties. Two basic requirements to establish any compound as a new drug are the development of a convenient extraction process and the characterization of its structural and thermal properties. In this work seven different methods were tested to optimize the extraction of AHR from Plectranthus grandidentatus. Supercritical fluid extraction (SFE) proved to be the method of choice, delivering an amount of AHR (57.351 μg·mg-1) approximately six times higher than the second best method (maceration in acetone; 9.77 μg·mg-1). Single crystal X-ray diffraction analysis of the ARH molecular and crystal structure carried out at 167 ± 2 K and 296 ± 2 K showed only a single phase, here dubbed form III (orthorhombic space group P21212), at those temperatures. The presence of two other polymorphs above room temperature was, however, evidenced by differential scanning calorimetry (DSC). The three forms are enantiotropically related, with the form III → form II and form II → form I transitions occurring at 333.5 ± 1.6 K and 352.0 ± 1.6 K, respectively. The fact that the transitions are reversible suggests that polymorphism is not likely to be an issue in the development pharmaceutical formulations based on ARH. DSC experiments also showed that the compound decomposes on melting at 500.8 ± 0.8 K. Melting should therefore be avoided if, for example, strategies to improve solubility based on the production of glassy materials or solid dispersions are considered.

Comparison of sunscreens Containing Titanium Dioxide Alone Or In Association With Cocoa, Murumuru Or Cupuaçu Butters: Comparação de Protetores Solares Contendo Dióxido De Titânio Associado Ou Não A Manteigas De Cacau, Murumuru Ou Cupuaçu

Ingredients of natural origin may represent alternatives for formulating sunscreens, without compromising their effectiveness. The literature has shown the antioxidant potential of compounds existing in murumuru (Astrocaryum murmuru), cupuaçu (Theobroma grandiflorum) and cocoa (Theobroma cacao) butters that recommends further investigation. The objectives of this research were: (1) to develop bioactive photoprotective formulations containing cocoa, murmuru or cupuaçu butters in association with a physical sunscreen (titanium dioxide (TiO2)) and (2) determine the possible photoprotective activity of butters and their interactions with the sunscreen. Cocoa, cupuaçu and murumuru butter were individually associated to TiO2 in O / W emulsions. The anti-UVA and UVB efficacy in vitro was estimated by diffuse transmittance analysis in a Labsphere® UV2000S, using quartz plates and Transpore® tape to obtain the SPF (sun protection factor) and critical wavelength. Photoprotective formulations containing titanium dioxide and bioactive butters were obtained using Aristoflex® AVC and triglycerides of caprylic capric acid (GTCC). The SPF of the samples containing only TiO2 and formulations containing cocoa, murumuru or cupuassu butters associated with TiO2 ranged from 4 to 5. The critical wavelength values for these formulations ranged from 383.0 to 386.7 nm. The results indicated no increase in the SPF value for formulations containing vegetable butters. The critical wavelength values indicated their potential to absorb part of the UVA radiation.

Photostabilization of sunscreens by incorporation of tea as the external phase: Fotoestabilização de protectores solares por incorporação de chás como fase externa

The use of isolated ultraviolet (UV) filters in photoprotective formulations creates products with limited protection against radiation, emphasising the need to develop formulations containing UVA and UVB filter combinations. However, most of the formulations developed to include both filters are unstable as a result of this combination, as well as by exposure to UV radiation. It is, therefore, crucial to include additives that enable photostabilization. Tea is the second most widely consumed beverage in the world and represents a good source of bioactive compounds, particularly polyphenols, which provide antioxidant activity. In the present work formulations containing green tea or black tea, as well as the sunscreens avobenzone (UVA sunscreen) and octilmetoxinamato (UVB sunscreen), were developed and evaluated in order to develop new and effective photostable formulations providing broad spectrum photoprotection. These formulations have been developed with complete replacement of the external phase of the oil in water (O/W) emulsion by these teas. The results showed that both teas presented photostabilizing capacity, particularly for green tea in the storage conditions at room temperature and at 5 °C, and black tea for the samples stored at 40 °C. Key-words: green tea, black tea, photoprotective formulations, photostabilizing capacity, octyl methoxynnamate, avobenzone

Impact of stirring speed, glycerin and sodium chloride concentrations on photoprotective nanoemulsions: Impacto da velocidade de agitação, contração de glicerina e de cloreto de sódio em nanoemulsões fotoprotetoras

New technologies that improve the physical as the sensory properties of sunscreens can help to increase its continued use and impact on health. The use of nanoemulsions in the development of photoprotective vehicles is an advantage, since nanostructured components may have superior properties regarding their performance when compared to conventional products. The advantages of using nanobiotechnology in manufacture of cosmetic and dermatological formulations arise from the protection of compounds from chemical or enzymatic degradation, from the control of their release, and also to the prolonged retention time of cosmetic ingredients in the stratum corneum. Thus, this study aimed to evaluate the impact of stirring speed and of glycerin and sodium chloride concentrations in the development and effectiveness of a nanoemulsion containing ethylhexyl methoxycinnamate and benzophenone-3. The results of statistical analyses regarding the impact of the variables in the process of nanoemulsion development showed that these parameters affect the phase inversion temperature (PIT). However, this did not affect the particle size and the photoprotective efficacy in vitro. Key-words: Nanoemulsion; Photoprotection; Ethylhexyl methoxycinnamate; Benzophenone-3