New strategy of multiple emulsion formation based on the interactions between polymeric emulsifier and natural ingredients

Preparation of Cosmetic Emulsions Containing Hippophae Oil Isolated by Various Methods: Study of Their Antioxidant, Sun-Blocking and Physicochemical Properties

An industry listed as one of the largest globally is the cosmetic industry. In recent years, this industry has shown growing interest in the application of natural ingredients providing advanced properties to cosmetic creams such as moisturizing, antioxidant, sun-protecting and antimicrobial effects. In this context, the present study concerns the production of cosmetic emulsions containing hippophae oil obtained via the methods of extraction, hydro-distillation and maceration using sunflower oil as the carrier oil. Firstly, an IR-ATR analysis was performed showing that the oils prepared were close to those commercially obtained. Then, the stability of the emulsions was tested over a time period of four months through measuring their pH and viscosity values with positive outcomes, and their antioxidant ability was also measured using the DPPH method. The latter one showed that hippophae oil greatly improves the antioxidant capacity. Moreover, based on the fact that sea buckthorn contains carotenoids, the SPF value of the emulsions was determined. The results showed that the addition of hippophae oil to the emulsions gave higher absorption in UV-Vis, thus higher SPF values. Py-GC/MS analysis was used to identify decomposition compounds in the produced oils. Among those, valuable compounds such as Ω-6, Ω-7 and Ω-9 fatty acids and many aldehydes were found by the decomposition of the oils.

Engineering linker defects in functionalized UiO-66 MOF nanoparticles for oil-in-water Pickering emulsion stabilization

Designing metal-organic framework (MOF)-based solid nanoparticles to stabilize Pickering emulsions by fine-tuning their hydrophobicity and lipophobicity is vital for essential applications and fundamental understanding. We demonstrate in situ grafting of palmitic acid in UiO-66 MOF through its linker defects. Our designed and activated nanoparticles (denoted as UP') stabilized the Pickering emulsions of n-heptane-in-water. Furthermore, we showed how UP' stabilized emulsion droplets disperse in media by covering each tiny droplet with a nanoscale layer made of UP'. To support our claim, we carried out the freeze-drying process to remove the liquid part from the emulsion, leaving behind the solid shell-like microstructures that we further characterized through several microscopic techniques. The stable n-heptane-in-water emulsion was confirmed by dilution (drop test), conductivity, zeta potential, and theoretical surface electrostatic potential measurements. Rheological studies indicate that the Pickering emulsions of n-heptane-in-water stabilized by UP' are much more resistant to deformation and flow imparting higher (mechanical) stability and shelf-life. Pickering emulsions stabilized by UP' emerged as a versatile way to design smart functional materials of UiO-66 through engineering linker defects that may have potential applications in interfacial catalysis, dye or contaminant separation, etc.

Multiple Pickering emulsions stabilized by the same particles with different extent of hydrophobization in situ

Multiple emulsions are widely used in pharmaceuticals, foods, and cosmetics. However, those stabilized by surfactants with different HLB values are generally unstable due to the diffusion of the surfactants between inner and outer interfaces. Here, we report that multiple W/O/W emulsions can be prepared by using the same particles in combination with a surfactant of different concentrations. The less surface-active raw CaCO₃ nanoparticles can be hydrophobized to surface-active in situ by adsorption of the anionic surfactant SDS, and the wettability of the particles can be controlled to be suitable for stabilizing both O/W and W/O Pickering emulsions by adjusting the surfactant concentration. With toluene as oil phase, the CaCO₃ particles at 1.0 wt% tend to stabilize a W/O emulsion in the presence of 3 mm SDS in an aqueous solution, which can then be further dispersed in an aqueous phase with 1.0 wt% CaCO₃ and SDS below 1 mm to form a W/O/W multiple emulsion. The effects of the ratio of W/O emulsion to the outer water phase and the preparation methods on stabilization of multiple emulsions were examined. With a ratio smaller than 3:1 and by gentle magnetic stirring, the multiple emulsions obtained can stay stable for at least a month without coalescence. This simple method not only ensures stabilization of multiple emulsions but also avoids complicated synthesis of colloid particles with different wettability.

Quality by design enabled the development of stable and effective oil-in-water emulsions at compounding pharmacy: the case of a sunscreen formulation

It is widely accepted that the use of topical sunscreens has medical importance with potential to prevent skin damage by protecting from solar ultraviolet radiation (UVR) effects. Pharmaceutical emulsions require an optimal qualitative and quantitative combination of emollients, emulsifiers and others compounds such as softening agents and, for sunscreens, a combination of chemical and physical UV filters. Herein, we applied the quality by design (QbD) concept to achieve stable and effective compounded sunscreen emulsions. By using the statistical tool of design of experiments, it was possible to identify the influence of emulsifier type (with low and high Hydrophile-Lipophile Balance) and concentrations of emollient and softening agent on the achievement of formulations with suitable organoleptic and physicochemical features. Compounded emulsions with pleasant macroscopic aspects were obtained. Three formulations with physicochemical properties in targeted ranges were selected, namely pH ∼6.0, conductivity > 0.0 µS/cm², spreadability factor ∼1-1.5 g/mm², viscosity ∼12000 mPa.s and sunscreen protection factor ∼30. Freeze-thaw cycle and accelerated stability study under different storage conditions allowed selecting a stable emulsion that ensured photoprotection in biological assays. The QbD approach was essential to select the best, low-cost compounded sunscreen emulsion, with targeted physicochemical parameters.

In Vitro and Clinical Safety Assessment of the Multiple W/O/W Emulsion Based on the Active Ingredients from Rosmarinus officinalis L., Avena sativa L. and Linum usitatissimum L

The multiple W/O/W emulsion supplemented with the extracts of Rosmarinus officinalis L., Avena sativa L. and Linum usitatissimum L. was prepared in the study, its active compounds were determined by HPLC and its safety was evaluated in vitro by the means of reconstituted human skin model EpiDerm™ for the assessment of its irritation, phototoxicity and early skin inflammation effects and by the 48 h human skin patch test for its skin irritation and allergenic potential. The microbiological challenge test of W/O/W emulsion was performed to ensure its preservation efficiency. The results showed that the W/O/W emulsion loaded with self-preserving plant-based bio-actives had no irritant potential, was not phototoxic and did not provoke skin inflammation or sensitization and thus could be used as a safe base for cosmetic products. Furthermore, our results demonstrate that the safety evaluation of cosmetic ingredients of natural or organic origin could be easily performed using reconstructed human skin model EpiDerm™ similar to the well-defined chemicals used in the cosmetics industry.

Accelerate development of topical cream drug product using a common platform base formulation

The aim of this work was to identify stable topical platform cream formulations (placebo creams without active drug substance) using the quality attributes of cream consistency, droplet size distribution (<1 μm), and separation or instability index of <0.1 to accelerate the development of topical cream drug product. The formulations were developed with six emulsifier systems that were screened in three different solvent systems across a range of emulsifier ratios. Each formulation was characterized by microscopy, separation index, and consistency. The results showed that there are three emulsifier combination (PEG 40 stearate:GMS, S21:S2, and PEG 40 stearate:Span 60) that works well with the solvent systems. Platform cream formulations F4, F15, F33, F40, F52, F69, F77, F87, and F106 were found to meet the three criteria for a long-term stable platform cream formulation. Formulation development for topical administered drug product can be very time consuming, expensive, and resourceful in identifying a chemically and physically stable product. In early development, where it can take 1-2 years to develop a first time in human (FTIH) formulation for a new chemical entity. The use of the platform base cream formulations will expedite the early development timeline for new chemical entity by 3-6 months.

Impact of the Mode of Extraction on the Lipidomic Profile of Oils Obtained from Selected Amazonian Fruits

Oils and fats are important raw materials in food products, animal feed, cosmetics, and pharmaceuticals among others. The market today is dominated by oils derive, d from African palm, soybean, oilseed and animal fats. Colombia's Amazon region has endemic palms such as Euterpe precatoria (açai), Oenocarpus bataua (patawa), and Mauritia flexuosa (buriti) which grow in abundance and produce a large amount of ethereal extract. However, as these oils have never been used for any economic purpose, little is known about their chemical composition or their potential as natural ingredients for the cosmetics or food industries. In order to fill this gap, we decided to characterize the lipids present in the fruits of these palms. We began by extracting the oils using mechanical and solvent-based approaches. The oils were evaluated by quantifying the quality indices and their lipidomic profiles. The main components of these profiles were triglycerides, followed by diglycerides, fatty acids, acylcarnitine, ceramides, ergosterol, lysophosphatidylcholine, phosphatidyl ethanolamine, and sphingolipids. The results suggest that solvent extraction helped increase the diglyceride concentration in the three analyzed fruits. Unsaturated lipids were predominant in all three fruits and triolein was the most abundant compound. Characterization of the oils provides important insights into the way they might behave as potential ingredients of a range of products. The sustainable use of these oils may have considerable economic potential.

Application of α-amylase as a novel biodemulsifier for destabilizing amphiphilic polymer-flooding produced liquid treatment

The performance and de-emulsification mechanism of α-amylase, a novel environmental friendly biodemulsifier in petroleum industry, was investigated at room temperature. The effects of α-amylase on the viscosity of amphiphilic polymer solution and de-emulsification rate were studied by changing the concentration of α-amylase, temperature and salinity. Polymer molecular weight, Zeta potential, interfacial film strength and interfacial tension were measured to investigate the de-emulsification mechanism of α-amylase. The results show that α-amylase is an efficient biodemulsifier to increase the de-emulsification rate of amphiphilic polymer emulsions. Hydrolysis of α-amylase to amphiphilic polymers destroys the structure of the amphiphilic polymer, thereby reduces the viscosity and the interfacial film strength of the system. Once de-emulsification is completed, the lower layer, i.e. the emulsified layer, will be clear. Thus, α-amylase can be applied as an effective de-emulsifier for amphiphilic polymer-stabilized O/W emulsion.

Innovative Natural Ingredients-Based Multiple Emulsions: The Effect on Human Skin Moisture, Sebum Content, Pore Size and Pigmentation

The increased interest in natural cosmetics has resulted in a higher market demand for preservative-free products based on herbal ingredients. An innovative W/O/W type emulsions containing herbal extracts were prepared directly; its cation form was induced by an ethanolic rosemary extract and stabilized using weak herbal gels. Due to the wide phytochemical composition of herbal extracts and the presence of alcohol in the emulsion system, which can cause skin irritation, sensitization or dryness when applied topically, the safety of the investigated drug delivery system is necessary. The aim of our study was to estimate the potential of W/O/W emulsions based on natural ingredients for skin irritation and phototoxicity using reconstructed 3D epidermis models in vitro and to evaluate in vivo its effect on human skin moisture, sebum content and pigmentation by biomedical examination using a dermatoscopic camera and corneometer. According to the results obtained after in vitro cell viability test the investigated emulsion was neither irritant nor phototoxic to human skin keratinocytes. W/O/W emulsion did not cause skin dryness in vivo, despite the fact that it contained ethanol. We can conclude that the emulsion is safe for use as a leave-on product due to the positive effect on human skin characteristics or as a semisolid pharmaceutical base where active compounds could be encapsulated.

The optimization of technological processes, stability and microbiological evaluation of innovative natural ingredients-based multiple emulsion

For the last couple of decades, multiple emulsions were prepared either by the re-emulsification of primary emulsion or they were produced by an emulsion inversion and their technological peculiarities were widely investigated. The aim of our study was to investigate and determine the optimal technological parameters of innovative multiple emulsion, prepared directly-by addition of ethanolic rosemary extract in the presence of polymeric emulsifier-and evaluate its stability by experimental surface response design approach. The results revealed that simplified W/O/W emulsification process is stirring time and stirring speed sensitive: the change of stirring time from 5 to 15 min at 600 rpm resulted in increased viscosity (from 1705.6 ± 62.2 to 3364.1 ± 112.5 mPA/s) and smaller oil droplet size (from 33.09 ± 1.51 to 17.81 ± 0.78 μm), though the conductivity increased from 800 ± 2 to 882 ± 2 μS/cm (p < .05). The second mixing stage (1000 rpm) had a negative effect on the conductivity of W/O/W emulsion because of the inner aqueous phase encapsulation efficiency. Ethanolic rosemary extract was used as multifunctional agent: not only to form multiple emulsion but also to preserve it; microbiological assay confirmed its effectiveness. A stable W/O/W type drug delivery system was successfully created without additional technological stages, phase inversion or surfactants.