Preparation of alpha-bisabolol and phenylethyl resorcinol/TiO2 hybrid composites for potential applications in cosmetics

In Vitro Photoprotection and Functional Photostability of Sunscreen Lipsticks Containing Inorganic Active Compounds

Titanium dioxide (TiO2) is a safe inorganic ultraviolet (UV) filter with activity against UV damage. However, the recombination of the carrier’s charge and the tendency for TiO2 aggregation are the main disadvantages. Substrate supports, such as mesoporous silica, are biocompatible strategies to incorporate TiO2, altering its interaction with the skin. Since the lips are sensitive to the adversities of the environment, including UV radiation, the application of lipstick sunscreens is of great importance and expected to provide protection for this particular area against sunburn and photoaging, among other unfavorable responses unprotected UV exposure. We investigated the in vitro photoprotective efficacy and photostability of lipstick formulations containing TiO2 incorporated into mesoporous silica (SBA-15). The samples were the lipstick base; SBA-15; TiO2 (free form); and TiO2 incorporated into SBA-15. The photoprotective efficacy was characterized in vitro using a Labsphere UV2000S. Lipsticks were irradiated in a Suntest CPS+ chamber to evaluate functional photostability. Lipstick base and SBA-15 alone did not display photoprotective efficacy. The sample containing 10.0% TiO2 incorporated into the mesoporous silica generated greater photostability and sun protection factor (SPF) value compared to the one containing only 10.0% TiO2 (free state). Our findings suggest that TiO2 + SBA-15 can be considered a broad-spectrum ingredient for innovative sunscreens, particularly for the photoprotection of the lips.

Effects of Nanobubbles in Dermal Delivery of Drugs and Cosmetics

Dermal delivery, which delivers drugs and cosmetics through the skin, has attracted significant attention due to its non-invasive and simple administration compared with oral or injectable administration. However, delivery of the ingredients through the skin barrier is difficult because the primary function of the skin is to protect the human body by preventing the invasion of contaminants. Although various techniques have been developed to overcome skin barriers, chemical toxicity, complicated processes, and expensive equipment still remain as obstacles. Moreover, green chemistry, which minimizes or eliminates the use of toxic chemicals, is required in the cosmetic industry. Thus, the development of a new method for dermal delivery is required. In this study, we provide a new method for dermal delivery using nanobubbles (NBs). NBs generated in oil improve the delivery effect of the active ingredients through the high Brownian motion and charge-balancing effect. Franz cell experiments and depigmentation experiments using the B16F10 melanoma cells were conducted to confirm the enhanced delivery effects. The system using NBs will contribute to the advancement of the dermal delivery of drugs and cosmetics.

Preclinical and clinical studies to evaluate cutaneous biodistribution, safety and efficacy of UV filters encapsulated in mesoporous silica SBA-15

Innovative technologies have been designed to improve efficacy and safety of chemical UV filters. Encapsulation can enhance efficacy and reduce transdermal permeation and systemic exposure. The aims of this work were (i) to determine the cutaneous biodistribution of avobenzone (AVO), oxybenzone (OXY), and octyl methoxycinnamate (OMC) incorporated in mesoporous silica SBA-15 and (ii) to perform preclinical (in vitro) and (iii) clinical safety studies to demonstrate their innocuity and to evaluate sun protection factor (SPF) in humans. Skin penetration studies showed that deposition of OXY and AVO in porcine and human skin after application of stick formulation with incorporated filters (stick incorporated filters) was significantly lower than from a marketed (non-encapsulated) stick. Cutaneous deposition and transdermal permeation of OXY in and across human skin were 3.8-and 13.4- fold lower, respectively, after application of stick entrapped filters. Biodistribution results showed that encapsulation in SBA-15 decreased AVO and OXY penetration reaching porcine and human dermis. Greater deposition (and permeation) of OXY in porcine skin than in human skin, pointed to the role of follicular transport. Stick incorporated filters had good biocompatibility in vivo and safety profiles, even under sun-exposed conditions. Entrapment of UV filters improved the SPF by 26% and produced the same SPF profile as a marketed stick. Overall, the results showed that SBA-15 enabled safety and efficacy of UV filters to be increased.

Antioxidant Activity in Supramolecular Carotenoid Complexes Favored by Nonpolar Environment and Disfavored by Hydrogen Bonding

Carotenoids are well-known antioxidants. They have the ability to quench singlet oxygen and scavenge toxic free radicals preventing or reducing damage to living cells. We have found that carotenoids exhibit scavenging ability towards free radicals that increases nearly exponentially with increasing the carotenoid oxidation potential. With the oxidation potential being an important parameter in predicting antioxidant activity, we focus here on the different factors affecting it. This paper examines how the chain length and donor/acceptor substituents of carotenoids affect their oxidation potentials but, most importantly, presents the recent progress on the effect of polarity of the environment and orientation of the carotenoids on the oxidation potential in supramolecular complexes. The oxidation potential of a carotenoid in a nonpolar environment was found to be higher than in a polar environment. Moreover, in order to increase the photostability of the carotenoids in supramolecular complexes, a nonpolar environment is desired and the formation of hydrogen bonds should be avoided.

Functionalized Spiky Particles for Intracellular Biomolecular Delivery

The intracellular delivery of biomolecules is of significant importance yet challenging. In addition to the conventional delivery of nanomaterials that rely on biochemical pathways, vertical nanowires have been recently proposed to physically penetrate the cell membrane, thus enabling the direct release of biomolecules into the cytoplasm circumventing endosomal routes. However, due to the inherent attachment of the nanowires to a planar 2D substrate, nanowire cell penetrations are restricted to in vitro applications, and they are incapable of providing solution-based delivery. To overcome this structural limitation, we created polyethylenimine-functionalized microparticles covered with nanospikes, namely, "spiky particles", to deliver biomolecules by utilizing the nanospikes to penetrate the cell membrane. The nanospikes might penetrate the cell membrane during particle engulfment, and this enables the bound biomolecules to be released directly into the cytosol. TiO2 spiky particles were fabricated through hydrothermal routes, and they were demonstrated to be biocompatible with HeLa cells, macrophage-like RAW cells, and fibroblast-like 3T3-L1 cells. The polyethylenimine-functionalized spiky particles provided direct delivery of fluorescent siRNA into cell cytosol and functional siRNA for gene knockdown as well as successful DNA plasmid transfection which were difficult to achieve by using microparticles without nanospikes. The spiky particles presented a unique direct cell membrane penetrant vehicle to introduce biomolecules into cell cytosol, where the biomolecules might bypass conventional endocytic degradation routes.

Vesicular carriers containing phenylethyl resorcinol for topical delivery system; liposomes, transfersomes and invasomes

Topical administration of phenylethyl resorcinol (PR) has attracted much attention as skin lightening agent with potent anti-tyrosinase activity. Two novel types of elastic carriers were developed to overcome the limitation of PR as topical delivery by increasing the solubility, stability and decreasing skin irritation compared to conventional liposomes. In addition, it also promotes skin penetration of PR to reach deep skin layer at the target site. The lead formulations were obtained from the invasomes containing 1% (w/v) d-limonene mixed with 10% (v/v) absolute ethanol as the skin enhancer, and transfersomes containing 15% (w/w) sodium deoxycholate (SDC) as edge activator. All formulations gave a vesicle size < 500 nm, polydispersity index (PDI) < 0.3, high zeta potential, entrapment efficiency > 50%, and good stability on storage at 30 °C at 75% RH for 4 months. Transfersomes have a lower degree of deformability (6.63%) than invasomes (25.26%). In contrast, the liposomes as rigid vesicles do not show a deformable property. This characteristic affects the skin permeation, and thus, transfersomes with high elastic property provided a significantly higher cumulative amount, steady state flux (J ss) and permeability coefficient (Kp ) compared to other formulations. However, in vitro PR accumulation in full-thickness newborn pig skin demonstrated that the application of elastic carrier formulations gave significantly higher accumulation than liposomes, and gave anti-tyrosinase activity up to 80%. These results are straightforwardly related to the results of cellular level study. Transfersomes and invasomes showed higher tyrosinase inhibition activity and melanin content reduction when compared to liposomes in B16 melanoma cells. In addition, acute irritation test in rabbits confirmed that these formulations are safe for skin application. Therefore, elastic vesicle carriers have the efficiency to deliver PR into the deep skin in both quantity and effectiveness which are better than conventional liposomes and appropriate for a skin lightening product.

Nanospikes-mediated Anomalous Dispersities of Hydropobic Micro-objects and their Application for Oil Emulsion Cleaning

Many fields of applications require dispersion of hydrophobic particles in water, which is traditionally achieved by using surfactants or amphiphilic molecules to modify particle surfaces. However, surfactants or amphiphilic molecules may disturb the native solution or particles' surface hydrophobicity, limiting extended applications such as oil emulsion cleaning. Recently one example of 2 μm-size polystyrene microparticles covered with ZnO nanospikes has been shown to exhibit excellent dispersity in water in spite of surface hydrophobicity. Whether this anomalous dispersion phenomenon was applicable to other hydrophobic microparticle systems was still unclear and its application scope was limited. Here the anomalous dispersities of different hydrophobic spiky micro-objects were systematically explored. The results show that the anomalous dispersion phenomenon was universally observed on different hydrophobic spiky micro-objects including different hydrophobic coating, particle sizes, material compositions and core particle morphologies. In addition, the spiky micro-objects displayed anomalous dispersity in water without compromising surface hydrophobicity, and their applications for oil spills absorption and oil emulsion cleaning were demonstrated. This work offers unique insight on the nanospikes-mediated anomalous dispersion phenomenon of hydrophobic micro-object and potentially extends its applicability and application scopes.