Predicting skin penetration of actives from complex cosmetic formulations: an evaluation of inter formulation and inter active effects during formulation optimization for transdermal delivery

Twenty products, containing a radiolabelled form of each active in typical cosmetic formulations, were made and applied to female human epidermal membranes mounted in Franz diffusion cells for 48 h under ‘in use’ conditions. The products consisted of combinations of five formulations (a hydro‐alcoholic gel, an oil in water emulsion, a water in oil emulsion, a microemulsion and an oil) with four model drug actives (testosterone, hydrocortisone, 5‐fluorouracil and ketoconazole). Steady‐state flux appeared to be reached by 8 h and maintained for all products, other than for the microemulsions, consistent with the actives being present in the residual formulation on the skin at saturation. The recovery for each active at the end of the 48‐h study (from a series of stratum corneum tape strips, the remaining skin, cumulative amount penetrating into the receptor solution, product washed from the skin and on the donor chamber cap) ranged from 86.5% to 100.6%. The rank order of the fluxes for the actives from the hydro‐alcoholic gel is consistent with the known active molecular size and polarity determinants for maximum epidermal flux. Actives with similar steady‐state (maximum) fluxes from a range of formulations had retention in the stratum corneum and similar transport rate constants through the stratum corneum. The microemulsion formulation significantly enhanced both the stratum corneum steady‐state flux and transport rate constant for 5‐fluorouracil, hydrocortisone and testosterone. The penetration flux of each active could be related to its size and polarity and appeared maximal when the actives in the different cosmetic formulations applied to the skin under ‘in use’ conditions were likely to remain in the residual product on the skin as a saturated solution after solvent evaporation. Enhanced penetration fluxes can be achieved by formulation selection and an appropriate choice/mix of emollients/adjuvants. The principles described here provide a framework for understanding the delivery of cosmetic ingredients from various formulations.     

Physical,antimicrobial and antibiofilm properties of Zataria multiflora Boiss essential oil nanoemulsion

It was evaluated physical, antibacterial and antibiofilm properties of Zataria multiflora Boiss essential oil (ZEO) and its nanoemulsion. Long‐term stability of nanoemulsion prepared by emulsion phase inversion was satisfying based on low narrow size distribution (polydispersity index ?0.2) and low droplet size (200 nm) over 21 days of storage. Nanoemulsion showed lower minimum inhibitory concentration (MIC) on Listeria monocytogenes (2500 µg mL^?1) than Salmonella Typhimurium (5000 µg mL^?1). Killing kinetics study revealed that nanoemulsion was more effective in inhibiting the growth of bacteria in milk than culture media. Both bacteriostatic and bactericidal effects were observed depending on the type of bacteria, nanoemulsion concentration and the time of exposure. Nanoemulsion at 4×MIC concentration reduced 64% and 75% of one‐day‐old biofilm of L. monocytogenes and S. Typhimurium, respectively. In conclusion, nanoemulsion revealed antimicrobial activity, but converting the ZEO to nanoemulsion did not improve its antibacterial activity; however, antibiofilm properties were enhanced.     

Insight into the phase inversion of a turmeric oil nanoemulsion in antifungal process

Antimicrobial essential oil nanoemulsions have been wildly applied in plant sterilisation. Here, a turmeric oil (TO) oil-in-water (O/W) nanoemulsion was developed to understand the antifungal mechanism between TO and Podosphaera xanthii (P. xanthii), simulating a moisture evaporation after spraying TO nanoemulsion on plant leaves. Dynamic light scattering (DLS) and cryogenic transmission electron microscopy (cryo-TEM) suggested the average hydrodynamic diameter of spherical TO nanoemulsion droplets was 150.2 nm with polydispersity index (PDI) of 0.17, which suggested no significant change after storing at 54 °C for 2 weeks. Atomic force microscope (AFM) as well as conductivity and viscosity demonstrated the phase inversion of droplets from O/W to water-in-oil (W/O) types during moisture evaporation is a primary mechanism to reveal the antifungal TO on cucumber leaves. Finally, the antifungal capacity of TO nanoemulsion was evaluated on living cucumber plants and demonstrated a remarkable antifungal effect on inhibiting the growth of P. xanthii.     

Utilisation of spontaneous emulsification to fabricate lutein‐loaded nanoemulsion‐based delivery systems: factors influencing particle size and colour

Factors influencing the formation and properties of lutein‐loaded nanoemulsions fabricated using spontaneous emulsification (SE) were investigated. Nanoemulsion formation depended on oil type: small droplets (diameter ≈ 200 nm) with a narrow monomodal particle size distribution (polydispersity index ≈ 0.23) could be formed using medium‐chain triglycerides (MCT), but not long‐chain triglycerides. Nanoemulsion formation also depended on surfactant type and concentration, with Tween 80 being the most effective surfactant. Optimisation of lutein‐loaded nanoemulsions formed by SE led to systems with a final composition of 10 wt% oil phase (0.12 wt% lutein + 9.88 wt% MCT), 10 wt% Tween 80, and 80 wt% aqueous phase. The nanoemulsions were stable to droplet aggregation when stored at ambient temperature for up to 1 month; however, some colour fading occurred due to lutein degradation. This study indicated the potential of nanoemulsion‐based delivery system fabricated using a low‐energy method for encapsulation and protection of lutein.     

Application of nanoemulsion‐based approaches for improving the quality and safety of muscle foods: A comprehensive review

Recently, there has been growing interest in implementing innovative nanoscience‐based technologies to improve the health, safety, and quality of food products. A major thrust in this area has been to use nanoemulsions because they can easily be formulated with existing food ingredients and technologies. In particular, oil‐in‐water nanoemulsions, which consist of small oil droplets (<200 nm) dispersed in water, are being utilized as delivery systems for various hydrophobic substances in foods, including nutrients, nutraceuticals, antioxidants, antimicrobials, colors, and flavors. In this article, we focus on the application of nanoemulsion‐based delivery systems for improving the quality, safety, nutritional profile, and sensory attributes of muscle foods, such as meat and fish. The article also critically reviews the formulation and fabrication of food‐grade nanoemulsions, their potential benefits and limitations in muscle food systems.     

The bioavailability of an omega‐3‐rich algal oil is improved by nanoemulsion technology using yogurt as a food vehicle

Global trends show that habitual omega‐3 intakes are short of recommended guidelines, particularly among vegetarians. Subsequently, alternative dietary sources of long‐chain omega‐3 polyunsaturated fatty acids (LC3PUFA) from vegetarian sources are needed. Food technology methods are advancing, and nanoemulsion technologies have improved the bioavailability of certain lipid‐based nutrients. This study examined whether ingestion of an omega‐3 algal oil nanoemulsion led to improved bioavailability compared to the bulk oil. Eleven subjects completed a single‐blind, randomised crossover trial, with a 21‐day washout between interventions. Results demonstrated that LC3PUFA absorption from the nanoemulsion was significantly higher than the bulk oil. Percentage blood fatty acids were significantly increased for docosahexaenoic acid (DHA; P ≤ 0.05) while LC3PUFA: PUFA ratios increased (P ≤ 0.05) and omega‐6:omega‐3 ratios were reduced (P = 0.028). Larger and longer intervention studies are now needed, but these preliminary findings demonstrate that nanoemulsion technology may improve the absorption of omega‐3 fatty acids.     

Absorption of whey protein isolated (WPI)-stabilized β-Carotene emulsions by oppositely charged oxidized starch microgels

β-Carotene is a natural antioxidant that is beneficial for human health. β-Carotene is well known for its aqueous insolubility and its sensitivity to environmental stimuli. To achieve the targeted delivery of β-Carotene to human intestine, a microgel system was developed. The microgel is made of oxidized potato starch polymers, which are obtained by chemical cross-link process by sodium trimetaphosphate (STMP). At pH < pI (WPI: pH 5), as in the acidic condition in stomach, the positively charged WPI emulsified β-Carotene nanoemulsion droplets were absorbed by the negatively charged starch microgel particles, which prevented the early release of β-Carotene in stomach. At pH > pI, as in the intestinal condition, WPI–β-Carotene nanoemulsion droplets and microgel particles both carry negative charges. Under this condition, β-Carotene will be released from microgel. In this study, we investigated the absorption capacity of β-Carotene nanoemulsion droplets by oxidized starch microgel particles of various degrees of oxidation (DO) and the cross-link density (R_{cross-linker/polymer(w/w)}) is investigated as a function of pH and salt concentrations. We found that DO30% with R_{cross-linker/polymer(w/w)} = 0.1 was the optimal gel type for nanoemulsion droplets absorption, and pH 3 and ionic strength of 0.06 M were the optimal conditions for nanoemulsion droplets absorption. The swelling capacity of the microgel particles rather than its ζ-potential was dominant in governing the absorption capacity. The in vitro release experiment under stimulated gastrointestinal fluids suggested that β-Carotene emulsions droplets remained stable at the gastric condition and were majorly released under the intestinal condition. The results suggested that the oxidized starch microgel could be used to prevent the early release of β-Carotene in the stomach and target delivery of them to the intestine.     

The effect of hydroxypropyl-guar nanoemulsion on signs and symptoms of dry eye

PurposeTo examine the effect of hydroxypropyl-guar nanoemulsion (HP-Guar nanoemulsion, Alcon Laboratories Ltd, Fort Worth, TX, USA) versus saline (0.9% sodium chloride; Pfizer Inc., Bentley WA Australia) on the comfort and tear film properties of people with dry eye disease both in the short-term (up to 2 h post-drop instillation) and longer-term (after 4 weeks of 4-times daily use), and to examine the effect on tear inflammatory markers after 4 weeks.MethodsThis was a prospective, investigator-masked, randomised, cross-over dispensing study. Twenty participants with dry eye disease (5 males: 15 females) with average age 46.9 ± 14.4 (range 26 to 70) years were randomized to either HP-Guar nanoemulsion, or saline eye drops. Ocular symptoms, lipid layer thickness, tear evaporation, tear osmolarity and non-invasive break-up time were measured pre-drop instillation, 1 h and 2 h post-eye drop instillation, and after 4-weeks of 4-times daily drop use. Tear inflammatory mediators were measured pre-drop instillation and after 4-weeks. After 4-weeks, patients had a 4-week washout period and then crossed over to the alternate drop.ResultsWith HP-Guar nanoemulsion, participants reported less grittiness/burning/stinging 1 h post eye drop instillation compared to baseline (79.5 ± 23.3 vs. 66.8 ± 27.7, p = 0.02); less dryness 1 h and 2 h post eye drop instillation compared to baseline (77.8 ± 23.0 and 76.2 ± 23.7 vs. 61.0 ± 27.1 respectively, p < 0.01 for both); and greater overall satisfaction 1 h post drop instillation and after 4 weeks of daily use compared to baseline (80.4 ± 21.6 and 83.4 ± 16.6 vs. 68.6 ± 26.0 respectively, p ≤ 0.011 for both). With saline, participants reported less dryness after 4 weeks of daily use compared to baseline (74.2 ± 23.8 vs. 60.2 ± 24.0, p < 0.01). For HP-Guar nanoemulsion, average lipid layer thickness was significantly thicker 2 h post drop-instillation (79.5 ± 21.7 nm) compared to baseline (63.7 ± 18.9 nm) and the 4-week assessment (62.4 ± 23.1 nm, p < 0.01 for both). For saline, average lipid layer thickness was significantly thicker at 1 h and 2 h post eye drop instillation (76.0 ± 23.8 nm and 80.4 ± 24.8 nm) compared to baseline (61.0 ± 15.6 nm, p < 0.01 for both). There was no difference in inflammatory mediators or other tear variables between drops or visits.ConclusionHP-Guar nanoemulsion was more effective for improving a range of subjective dry eye symptoms both in the short and long-term compared to saline. Both HP-Guar nanoemulsion and saline transiently increased lipid layer thickness.     

Characterization of Capsaicin-Loaded Nanoemulsions Stabilized with Alginate and Chitosan by Self-assembly

The objectives of this research were to characterize capsaicin-loaded nanoemulsions stabilized with natural biopolymer such as alginate and chitosan for use as a functional ingredient delivery system. The biopolymer nanoemulsion was prepared using self-assembly emulsification methods, and the capsaicin included oleoresin capsicum as the core material in the nanoemulsion. The particle sizes of the double-layer nanoemulsions prepared with alginate (AN) and chitosan (CN) were 20 nm or lower. The triple-layer nanoemulsion, which was prepared by complexation with chitosan and alginate (CAN), was successfully prepared with particle sizes on the nanoscale through the electrostatic interactions between the carboxylic groups and amine groups of the biopolymers. The Zeta potential value, which is an indicator of the overall stability and physicochemical properties of the nanoemulsion, of AN and CN were significantly higher than SN and CAN (p < 0.01). In conclusion, the double-layer nanoemulsions incorporated with alginate and chitosan can be expected to improve the stability of nanoemulsion. In addition, this system holds promise for use in the production of functional foods containing functional ingredients.     

Effect of antioxidants in combination of VCO nanoemulsion on gel properties and storage stability of refrigerated sardine surimi gel

Impacts of β-glucan–virgin coconut oil (VCO) nanoemulsion containing epigallocatechin gallate (EGCG) and α-tocopherol at levels of 0–3.0 g kg⁻¹ on properties and storage stability of surimi gel were investigated. Augmented breaking force, deformation and fracture constant were obtained in gels containing 2.0 g kg⁻¹ EGCG or 1.0 g kg⁻¹ α-tocopherol (P < 0.05). Expressible moisture content increased as EGCG levels were more than 2.0 g kg⁻¹. Smoother microstructure was observed in gels containing 2.0 g kg⁻¹ EGCG. Whiter gels were obtained when β-glucan–VCO nanoemulsion was incorporated. No change in protein pattern of gels was observed regardless of antioxidant incorporation. Viscoelastic moduli decreased as β-glucan–VCO nanoemulsion was added; however, incorporation of 2.0 g kg⁻¹ EGCG or 1.0 g kg⁻¹ α-tocopherol lowered the decrease in G'. β-glucan–VCO nanoemulsion containing gels had higher likeness scores than the control (P < 0.05). Gels containing EGCG and α-tocopherol at selected levels had the improved oxidative stability and lowered microbial loads.     

Infant skin physiology and development during the first years of life: a review of recent findings based on in vivo studies

Infant skin is often presented as the cosmetic ideal for adults. However, compared to adult skin it seems to be more prone to develop certain pathological conditions, such as atopic dermatitis and irritant contact dermatitis. Therefore, understanding the physiology of healthy infant skin as a point of reference is of interest both from the cosmetic as well as from the clinical point of view. Clinical research on healthy infants is, however, limited because of ethical considerations of using invasive methods and therefore until recently data has been scarce. Technical innovations and the availability of non‐invasive in vivo techniques, such as evaporimetry, electrical impedance measurement, in vivo video and confocal microscopy, and in vivo fibre‐optic based spectroscopy, opened up the field of in vivo infant skin physiology research. Studies incorporating such methods have demonstrated that compared to adult, infant skin continues to develop during the first years of life. Specifically, infant skin appears to have thinner epidermis and stratum corneum (SC) as well as smaller corneocytes at least until the second year of life. The water‐handling properties are not fully developed before the end of the first year and infant SC contains more water and less amounts of natural moisturizing factors. Such findings re‐evaluate the old notions that skin is fully matured at birth. Armed with this knowledge, we are in a position not only to better understand infant dermatological conditions but also to design better skin care products respecting the distinct qualities of infant skin.     

Physicochemical and antioxidative properties of Korean nanopowdered white ginseng

This study was carried out to investigate physicochemical and antioxidative properties of Korean nano white ginseng powder. The particle size of nanopowdered ginseng (NPG) was in the range from 600 to 1000 nm which was significantly smaller than the regular powdered ginseng (PG) which was in the range from 300 to 500 μm. Carbohydrate content was found to be significantly higher in NPG than PG (P < 0.05). Higher L value of NPG was mostly due to the higher light‐scattering effect of bright ginseng powder. In oil‐holding capacity, NPG was significantly higher than PG (P < 0.05). Total polyphenol content was not significantly different between NPG and PG, and it was in the range of 52.5% (P > 0.05). However, DPPH and ABTS studies showed that NPG has higher antioxidative properties than PG. In overall, NPG showed much higher antioxidative properties compared with PG. Thus, NPG enhances the functional value of Korean white ginseng powder.     

Properties of starch nanoparticle obtained by ultrasonication and high pressure homogenization for developing carotenoids-enriched powder and Pickering nanoemulsion

The effect of ultrasound (US) and high pressure homogenization (HPH) on starch nanoparticles and their ability to stabilize Pickering nanoemulsion of carotenoids and bioactives-enriched olive oil was evaluated. The carotenoids used in nanoemulsion were extracted from the peel of passion fruit (Passiflora edulis). As the US treatment time increased, mean particle size decreased from microsize to 340 nm and subsequent HPH treatment of this suspension caused further decrease in particles size (<60 nm). US and HPH treatments increased swelling and solubility and also the gelatinization and melting temperatures of the starch nanoparticles. The Pickering nanoemulsion was rich in carotenoids and total phenolic content and exhibited high antioxidant activity, which had protective effect on its stability. The carotenoids-enriched nanoemulsion was found to be stable to heat and freeze-thaw treatments. The developed nanoemulsion showed better oxidative stability as well as physical stability during storage at 6 °C and 25 °C.     

Characteristics and functional properties of gelatin from seabass skin as influenced by defatting

Gelatins from nondefatted and defatted seabass skins were characterised and evaluated for their functional properties in comparison with commercial fish skin gelatin. All gelatins contained α₁‐ and α₂‐chains as the predominant components and showed a high imino acid content (199–201 residues/1000 residues). All gelatins had a relative solubility greater than 90% in the wide pH ranges (1–10). Foaming properties of all gelatins increased with increasing concentrations (1–3%, w/v). Gelatin from defatted skin had higher foam expansion and stability than that extracted from nondefatted skin. Emulsion containing gelatin from defatted skin had smaller oil droplet size (d₃₂, d₄₃), compared with that having gelatin from nondefatted skin (P < 0.05). After 10 days of storage at room temperature (28–30 °C), emulsion stabilised by gelatin from defatted skin showed the higher stability as indicated by the lower increases in d₃₂ and d₄₃, and lower flocculation factor and coalescence index. Coincidentally, emulsion stabilised by gelatin from defatted skin had higher zeta potential than that containing gelatin from nondefatted skin. Thus, defatting of seabass skin directly affected characteristics and functional properties of resulting gelatin.     

Functional properties and antioxidative activity of protein hydrolysates from toothed ponyfish muscle treated with viscera extract from hybrid catfish

Functional properties and antioxidative activity of a protein hydrolysate prepared from toothed ponyfish (Gazza minuta) muscle, using viscera extract from hybrid catfish (Clarias macrocephalus × Clarias gariepinus), with a degree of hydrolysis (DH) of 70%, were investigated. The protein hydrolysate had a good solubility. It was soluble over a wide pH range (3–9), in which more than 77% solubility was obtained. The emulsifying activity index of the protein hydrolysate decreased with increasing concentration (P < 0.05). Conversely, the foaming abilities increased as the hydrolysate concentrations increased (P < 0.05). Protein hydrolysate exhibited the increases in 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical scavenging activities, ferric reducing power (FRAP) and metal chelating activity as hydrolysate concentration increased (P < 0.05). ABTS radical scavenging activity of protein hydrolysate was stable when heated at 100 °C for 180 min and subjected to a wide pH range (1–11). Therefore, protein hydrolysate from the muscle of toothed ponyfish produced by viscera extract from hybrid catfish can be used as a promising source of functional peptides with antioxidant properties.     

Rational construction of citrus essential oil nanoemulsion with robust stability and high antimicrobial activity based on combination of emulsifiers

We have successfully constructed citrus essential oil (CEO, d-limonene is its main active component) nanoemulsion by the high-pressure homogenization method, whose droplet size, polydispersity index, and zeta potential were 34.23 nm, 0.235, and −25.87 mV, respectively. The effects of thermal treatment (−20–48 °C), pH (5–9), ionic strength (100–500 mM NaCl) and storage time (200 days) were examined on the physicochemical properties of all treatments. The antimicrobial activity of nanoemulsion was tested by determining the minimal inhibitory concentration against the four foodborne microorganisms (Escherichia coli (10 mg/mL), Staphylococcus aureus (0.150 mg/mL), Bacillus subtilis (0.312 mg/mL) and Saccharomyces cerevisiae (0.312 mg/mL)). Especially, compared with pure CEO, the antibacterial activity of its nanoemulsion against S. aureus (0.150 mg/mL) and B. subtilis (0.312 mg/mL) was increased by 43 and 86 times respectively. Industrial relevance: In this work, we constructed robust CEO nanoemulsions based on a combination of emulsifiers via the high-pressure homogenization method, which bring new insights into the preparation of nanoemulsions. There is great potential for nanoencapsulation of natural compounds in the field of food preservation. Furthermore, the results may provide valuable data for industrial scale-up application.     

Enzymatic hydrolysis combined with high‐pressure homogenisation for the preparation of polysaccharide‐based nanoparticles from the by‐product of Flammulina velutipes

In this study, protease, α‐amylase and 5‰ β‐glucanase enzymolysis in combination with high‐pressure homogenisation were used for the preparation of polysaccharide‐based nanoparticles from Flammulina velutipes stipes, respectively, named FNP‐1, FNP‐2 and FNP‐3, and the nanoparticles were subsequently characterised. The FNP size distribution ranged from 50 nm to 300 nm, among which FNP‐2 and FNP‐3 were smaller than FNP‐1, based on the SEM images. GC‐MS results showed that these particles were mainly composed of glucose and glucosamine. The FNP dispersions at 1 wt% behaved as non‐Newtonian, shear‐thinning fluids, and the FNP‐3 dispersion presented superior viscoelasticity. With an increasing degree of enzymolysis, the thermal stability of the FNPs decreased. In addition, these particles presented various cation‐exchange properties. Therefore, the Flammulina velutipes polysaccharide‐based nanoparticles obtained from this study can be potentially used as a promising functional food ingredient in the food industry.     

Feasibility of incorporating buriti (Mauritia flexuosa L.) oil nanoemulsions in isotonic sports drink

Buriti (Mauritia flexuosa L.) oil is one of the richest vegetal sources of carotenoids, and its use in food industry is interesting considering the growing interest of the consumers for healthier products. Nanoemulsions of buriti oil were produced by phase inversion temperature (PIT) method for subsequent incorporation in isotonic beverage. The incorporation of nanoemulsions of buriti oil in beverages aims to replace artificial colouring by natural dyes. The nanoemulsion stability was evaluated by measuring average droplet size (73–86 nm), polydispersity (0.08–0.15), lipid oxidation quantification (0.05–0.1 mmol MDA kg^?1), and total carotenoids. The beverages were evaluated in terms of pH (2.72–3.05), osmolality, total titratable acidity (0.164–0.177 g citric acid L^?1), soluble solids (4.23–5.13 °Brix), and colorimetric parameters. Microbiology and sensory evaluation were also carried out, and the results indicated that buriti oil nanoemulsions can be incorporated in isotonic beverages.     

Rheological and physico‐chemical properties of gelatin extracted from the skin of a few species of freshwater carp

The physico‐chemical and rheological properties of gelatin from the skins of three different freshwater carp species, namely Catla catla, (catla) Cirrhinus mrigala (mrigal) and Labeo rohita (rohu), have been assessed and compared with that of gelatin from porcine skin. The average solids yield from the three species of carp varied in the range of 11.8–14.1%. The amino acid profile showed that the porcine gelatin had a higher proportion of imino acids and glycine than carp skins gelatin. The average molecular weight of carp skins gelatin as determined using a gel filtration technique was 233 kDa, while that of porcine skin gelatin was 282 kDa. The gelling temperature of carp skins gelatin was in the range of 6–15.7 °C, and the melting temperature was 17.9–23.7 °C as determined using a controlled stress rheometer. A higher gelling and melting temperature was observed for porcine skin gelatin.