Degradation of Perfluorooctanoic Acid on Aluminum Oxide Surfaces: New Mechanisms from Ab Initio Molecular Dynamics Simulations.

Perfluorooctanoic acid (PFOA) is a part of a large group of anthropogenic, persistent, and bioaccumulative contaminants known as per- and polyfluoroalkyl substances (PFAS) that can be harmful to human health. In this work, we present the first ab initio molecular dynamics (AIMD) study of temperature-dependent degradation dynamics of PFOA on (100) and (110) surfaces of γ-Al2O3. Our results show that PFOA degradation does not occur on the pristine (100) surface, even when carried out at high temperatures. However, introducing an oxygen vacancy on the (100) surface facilitates an ultrafast (<100 fs) defluorination of C-F bonds in PFOA. We also examined degradation dynamics on the (110) surface and found that PFOA interacts strongly with Al(III) centers on the surface of γ-Al2O3, resulting in a stepwise breaking of C-F, C-C, and C-COO bonds. Most importantly, at the end of the degradation process, strong Al-F bonds are formed on the mineralized γ-Al2O3 surface, which prevents further dissociation of fluorine into the surrounding environment. Taken together, our AIMD simulations provide critical reaction mechanisms at a quantum level of detail and highlight the importance of temperature effects, defects, and surface facets for PFOA degradation on reactive surfaces, which have not been systematically explored or analyzed.

Enhanced Biofilm Eradication and Reduced Cytotoxicity of a Novel Polygalacturonic and Caprylic Acid Wound Ointment Compared with Common Antiseptic Ointments.

Antiseptic wound ointments are widely used to treat dermal wounds that are microbially contaminated. Polygalacturonic acid (PG)+caprylic acid (CAP) is a novel combination that has been shown to eradicate biofilms. We developed a novel PG+CAP ointment and compared the biofilm eradication capability and cytotoxicity of PG+CAP with that of commercially available antiseptic wound ointments. We used a well-established biofilm model to quantitatively assess the eradication of organisms following exposure to the wound ointments for 2 hours. PG+CAP ointment completely eradicated Candida albicans, multidrug-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus biofilms, whereas MediHoney, polyhexamethylene biguanide (PHMB), and benzalkonium chloride (BZK) ointments failed to eradicate all biofilms within 2 hours. We assessed cytotoxicity by exposing L-929 fibroblasts to extracts of each ointment; Trypan blue exclusion was used to assess cell viability, and Alamar blue conversion was used to assess metabolic function. After exposure to PG+CAP and MediHoney, fibroblast viability was 96.23% and 95.23%, respectively (Trypan blue), and was comparable to untreated cells (98.77%). PHMB and BZK showed reduced viability (83.25% and 77.83%, respectively, p < 0.05). Metabolic activity results followed a similar pattern. Cytotoxicity of PG+CAP ointment towards erythrocytes was comparable to saline. PG+CAP ointment seems to be safe and can rapidly eradicate microbial biofilm; thus, PG+CAP ointment merits further in vivo testing as a potential antimicrobial wound ointment.

Discrimination and Identification of Aroma Profiles and Characterized Odorants in Citrus Blend Black Tea with Different Citrus Species.

Citrus blend black teas are popular worldwide, due to its unique flavor and remarkable health benefits. However, the aroma characteristics, aroma profiles and key odorants of it remain to be distinguished and cognized. In this study, the aroma profiles of 12 representative samples with three different cultivars including citrus (Citrus reticulata), bergamot (Citrus bergamia), and lemon (Citrus limon) were determined by a novel approach combined head space-solid phase microextraction (HS-SPME) with comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS). A total of 348 volatile compounds, among which comprised esters (60), alkenes (55), aldehydes (45), ketones (45), alcohols (37), aromatic hydrocarbons (20), and some others were ultimately identified. The further partial least squares discrimination analysis (PLS-DA) certified obvious differences existed among the three groups with a screening result of 30 significant differential key volatile compounds. A total of 61 aroma-active compounds that mostly presented green, fresh, fruity, and sweet odors were determined in three groups with gas chromatography-olfactometry/mass spectrometry (GC-O/MS) assisted analysis. Heptanal, limonene, linalool, and trans-ß-ionone were considered the fundamental odorants associated with the flavors of these teas. Comprehensive analysis showed that limonene, ethyl octanoate, copaene, ethyl butyrate (citrus), benzyl acetate, nerol (bergamot) and furfural (lemon) were determined as the characterized odorants for each type.

Application of surfactant modified montmorillonite with different conformation for photo-treatment of perfluorooctanoic acid by hydrated electrons.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a class of highly persistent contaminants with high bioaccumulation and toxicity. Our previous studies showed that perfluorooctanoic acid (PFOA) can be completely defluorinated under UV irradiation in organo-montmorillonite/indole acetic acid (IAA) system. However, there is still lack of information for the degradation mechanism and the test for wastewater treatment. Here, we systematically investigated the defluorination reaction in the presence of different organo-montmorillonites and found that the degradation process was apparently controlled by the configuration of surfactants. In hexadecyltrimethyl ammonium (HDTMA)-modified montmorillonite, HDTMA exists as a tilt conformation and isolated clay interlayer from the aqueous solution, protecting hydrated electrons generated by photo-irradiation of IAA from quenching by oxygen. Defluorination hydrogenation process was the dominant degradation pathway. While in poly-4-vinylpyridine-co-styrene (PVPcoS)-modified montmorillonite, due to the multiple charges of PVPcoS, a flat conformation parallel to clay surface was expected. Hydroxyl radicals, which were generated by the reaction of hydrated electrons with oxygen molecules diffused into clay interlayer, are also involved in the degradation process. Our results further demonstrate that mixture modified montmorillonite could combine the advantages of both modifications, thus showing superior reactivity even for actual industrial wastewater without any pretreatment. This technique would have great potential for treatment of actual wastewater.

RIFM fragrance ingredient safety assessment, methyl 2-octynoate, CAS Registry Number 111-12-6.

Methyl 2-octynoate was evaluated for genotoxicity, repeated dose toxicity, developmental and reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data show that methyl 2-octynoate is not genotoxic. Data provided methyl 2-octynoate a NESIL of 110 µg/cm2 for the skin sensitization endpoint. The repeated dose, developmental and reproductive, and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class II material, and the exposure to methyl 2-octynoate is below the TTC (0.009 mg/kg/day, 0.009 mg/kg/day, and 0.47 mg/day, respectively). The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; methyl 2-octynoate is not expected to be phototoxic/photoallergenic. The environmental endpoints were evaluated; methyl 2-octynoate was found not to be PBT as per the IFRA Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., PEC/PNEC), are <1.

Tacrolimus-loaded lecithin-based nanostructured lipid carrier and nanoemulsion with propylene glycol monocaprylate as a liquid lipid: Formulation characterization and assessment of dermal delivery compared to referent ointment.

Nanostructured lipid carriers (NLC) and nanoemulsions (NE) are colloid carriers which could improve dermal delivery of tacrolimus. The aims of this study were to evaluate effects of different formulation and process parameters on physicochemical characteristics and stability of lecithin-based NLC with glyceryl palmitostearate as solid and propylene glycol monocaprylate as liquid lipid and to compare the influence of different inner structure of tacrolimus-loaded NLC and corresponding NE on physicochemical characteristics, stability, entrapment efficiency, in vitro drug release and overall skin performance. Solid/liquid lipid ratio, total amount of lipids, homogenization pressure and cooling after the preparation were identified as critical variables in NLC development. Moreover, tacrolimus-loaded NLC emerged as more stabile carrier than NE. Differential stripping performed on porcine ear skin revealed significantly higher tacrolimus amount in stratum corneum from nanocarriers compared to referent ointment (Protopic®). Similarly the highest amount of tacrolimus in hair follicles was obtained using NLC (268.54 ±â€¯92.38 ng/cm2), followed by NE (128.17 ±â€¯48.87 ng/cm2) and Protopic® (77.61 ±â€¯43.25 ng/cm2). Contrary, the highest permeation rate through full-thickness porcine ear skin was observed for Protopic®, implying that the selection of experimental setup is critical for reliable skin performance assessment. Overall, developed NLC could be suggested as promising carrier in a form of lotion for tacrolimus dermal delivery.

Peak AAA fatty acid homolog contaminants present in the dietary supplement l-Tryptophan associated with the onset of eosinophilia-myalgia syndrome.

The eosinophilia-myalgia syndrome (EMS) outbreak that occurred in the USA and elsewhere in 1989 was caused by the ingestion of Showa Denko K.K. (SD) L-tryptophan (L-Trp). "Six compounds" detected in the L-Trp were reported as case-associated contaminants. Recently the final and most statistically significant contaminant, "Peak AAA" was structurally characterized. The "compound" was actually shown to be two structural isomers resulting from condensation reactions of L-Trp with fatty acids derived from the bacterial cell membrane. They were identified as the indole C-2 anteiso (AAA1-343) and linear (AAA2-343) aliphatic chain isomers. Based on those findings, we utilized a combination of on-line HPLC-electrospray ionization mass spectrometry (LC-MS), as well as both precursor and product ion tandem mass spectrometry (MS/MS) to facilitate identification of a homologous family of condensation products related to AAA1-343 and AAA2-343. We structurally characterized eight new AAA1-XXX/AAA2-XXX contaminants, where XXX represents the integer molecular ions of all the related homologs, differing by aliphatic chain length and isomer configuration. The contaminants were derived from the following fatty acids of the bacterial cell membrane, 5-methylheptanoic acid (anteiso-C8:0) for AAA1-315; n-octanoic acid (n-C8:0) for AAA2-315; 6-methyloctanoic acid (anteiso-C9:0) for AAA1-329; n-nonanoic acid (n-C9:0) for AAA2-329; 10-methyldodecanoic acid (anteiso-C13:0) for AAA1-385; n-tridecanoic acid (n-C13:0) for AAA2-385; 11-methyltridecanoic acid (anteiso-C14:0) for AAA1-399; and n-tetradecanoic acid (n-C14:0) for AAA2-399. The concentration levels for these contaminants were estimated to be 0.1-7.9 µg / 500 mg of an individual SD L-Trp tablet or capsule The structural similarity of these homologs to case-related contaminants of Spanish Toxic Oil Syndrome (TOS) is discussed.

Ultra-stable self-foaming oils.

This paper is concerned with the foaming of a range of fats in the absence of added foaming agent/emulsifier. By controlling the temperature on warming from the solid or cooling from the melt, crystals of high melting triglycerides form in a continuous phase of low melting triglycerides. Such crystal dispersions in oil can be aerated to produce whipped oils of high foamability and extremely high stability. The foams do not exhibit drainage and bubbles neither coarsen nor coalesce as they become coated with solid crystals. The majority of the findings relate to coconut oil but the same phenomenon occurs in shea butter, cocoa butter and palm kernel stearin. For each fat, there exists an optimum temperature for foaming at which the solid fat content reaches up to around 30%. We demonstrate that the oil foams are temperature-responsive and foam collapse can be controllably triggered by warming the foam to around the melting point of the crystals. Our hypothesis is given credence in the case of the pure system of tristearin crystals in liquid tricaprylin.

Unusual poly(3-hydroxyalkanoate) (PHA) biosynthesis behavior of Pseudomonas putida Bet001 and Delftia tsuruhatensis Bet002 isolated from palm oil mill effluent.

Pseudomonas putida Bet001 and Delftia tsuruhatensis Bet002, isolated from palm oil mill effluent, accumulated poly(3-hydroxyalkanoates) (PHAs) when grown on aliphatic fatty acids, sugars, and glycerol. The substrates were supplied at 20:1 C/N mole ratio. Among C-even n-alkanoic acids, myristic acid gave the highest PHA content 26 and 28 wt% in P. putida and D. tsuruhatensis, respectively. Among C-odd n-alkanoic acids, undecanoic gave the highest PHA content at 40 wt% in P. putida and 46 wt% in D. tsuruhatensis on pentadecanoic acid. Sugar and glycerol gave <10 wt% of PHA content for both bacteria. Interestingly, D. tsuruhatensis accumulated both short- and medium-chain length PHA when supplied with n-alkanoic acids ranging from octanoic to lauric, sucrose, and glycerol with 3-hydroxybutyrate as the major monomer unit. In P. putida, the major hydroxyalkanoates unit was 3-hydroxyoctanoate and 3-hydroxydecanoate when grown on C-even acids. Conversely, 3-hydroxyheptanoate, 3-hydrxoynonanoate, and 3-hydroxyundecanoate were accumulated with C-odd acids. Weight-averaged molecular weight (Mw ) was in the range of 53-81 kDa and 107-415 kDa for P. putida and D. tsuruhatensis, respectively. Calorimetric analyses indicated that both bacteria synthesized semicrystalline polymer with good thermal stability with degradation temperature (Td ) ranging from 178 to 282 °C.

Mesoporous SBA-15 Silica-supported Diisopropylguanidine: an Efficient Solid Catalyst for Interesterification of Soybean Oil with Methyl Octanoate or Methyl Decanoate.

The organosilane agent, namely 3-(N,N'-diisopropylguanidine)-propyltriethoxysilane, was firstly prepared by the reaction of diisopropylcarbodimide with (3-aminopropyl)triethoxysilane, and then employed for grafting guanidine base onto the surface of the mesoporous SBA-15 silica to afford an organic-inorganic hybrid catalyst. The prepared solid catalyst was fully characterized by various techniques such as small-angle X-ray power diffraction, Fourier transform infrared spectra, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption-desorption and elemental analysis techniques. The obtained results showed that the guanidine base was successfully tethered onto the SBA-15 silica and the ordered mesoporous structure of the SBA-15 material remained almost unchangeable after the orgnofunctionalization. The solid catalyst was found to have appreciable catalytic activities to the interesterification of soybean oil with methyl octanoate or methyl decanoate under solvent-free conditions. Influence of various reaction parameters, such as the substrate molar ratio, reaction temperature, catalyst loading and reaction time, on the catalytic interesterification was investigated to optimize the interesterification condition for the production of structured lipids containing medium-chain fatty acids. The hybrid solid catalyst was easily separated and reused for four runs without significant loss of catalytic activity.

Role of Dissolved Organic Matter in Sorption of Perfluorooctanoic Acid to Metal Oxides.

Perfluorooctanoic acid (PFOA) is an important perfluorinated chemical of significant environmental concern. It has been widely found at high concentrations in the environment. We have exposed sediment constituent minerals SiO2, Fe2O3, and Al2O3 to PFOA and humic acid (HA) and studied the adsorption of PFOA by introducing the adsorbates in different orders. The results suggest concurrent sorption of PFOA and HA to the mineral surface or enhanced PFOA sorption when both are introduced to the aqueous phase. However, when PFOA is introduced to the mineral surface that has already been exposed to and extensively coated with HA, little PFOA adsorption occurs, which implies that PFOA released to rivers rich in dissolved organic matter (DOM, i.e. HA) may be immune to sorptive retention by the sediment and be transported downstream unabated. DOM thus can play a significant role in the transport and fate of PFOA in the natural water system.

Effect of interfacial composition and crumbliness on aroma release in soy protein/sugar beet pectin mixed emulsion gels.

BACKGROUND: In this study, soy protein isolate/sugar beet pectin (SPI/SBP) emulsion gels were prepared through an enzymatic gelation process. The effects of emulsifier (SBP, SPI or SPI/SBP complex) and emulsification process on the microstructure, texture, breakdown properties and aroma release behavior of resulting emulsion gels were investigated. RESULTS: Oil emulsification by SBP/SPI complex resulted in a higher amount of emulsifier absorbing on the oil-water interface than by SBP and SPI alone, indicating that a more compact interfacial network was formed. Flocculation of oil droplets was observed and corresponding emulsion gels exhibited lower fracture force and strain when the oil was emulsified by SPI and SBP/SPI complex. Moreover, emulsion gels with small droplets produced a greater quantity of small fragments after mastication. However, microstructure did not have a significant effect on breakdown properties of emulsion gels. Headspace gas chromatography analysis showed that the release rate of ethyl butyrate before and after mastication was significantly lower in emulsion gel with more compact network, but the release of aroma compounds with higher hydrophobicity did not show a significant influence of the microstructure and texture of emulsion gel. CONCLUSION: This finding provides a useful application for designing semi-solid foods with desirable flavor perception. © 2016 Society of Chemical Industry.

The disulfide compound α-lipoic acid and its derivatives: A novel class of anticancer agents targeting mitochondria.

The endogenous disulfide α-lipoic acid (LA) is an essential mitochondrial co-factor. In addition, LA and its reduced counterpart dihydro lipoic acid form a potent redox couple with antioxidative functions, for which it is used as dietary supplement and therapeutic. Recently, it has gained attention due to its cytotoxic effects in cancer cells, which is the key aspect of this review. We initially recapitulate the dietary occurrence, gastrointestinal absorption and pharmacokinetics of LA, illustrating its diverse antioxidative mechanisms. We then focus on its mode of action in cancer cells, in which it triggers primarily the mitochondrial pathway of apoptosis, whereas non-transformed primary cells are hardly affected. Furthermore, LA impairs oncogenic signaling and displays anti-metastatic potential. Novel LA derivatives such as CPI-613, which target mitochondrial energy metabolism, are described and recent pre-clinical studies are presented, which demonstrate that LA and its derivatives exert antitumor activity in vivo. Finally, we highlight clinical studies currently performed with the LA analog CPI-613. In summary, LA and its derivatives are promising candidates to complement the arsenal of established anticancer drugs due to their mitochondria-targeted mode of action and non-genotoxic properties.

Kinetically stable propofol emulsions with reduced free drug concentration for intravenous delivery.

PURPOSE: Intravenous injections of propofol emulsions are accompanied by pain likely due to the interaction of the dissolved drug with endothelial cells of the vasculature. It is commonly hypothesized that reducing the aqueous phase concentration of propofol could reduce pain. METHODS: To minimize the propofol concentration in the aqueous phase, we developed stable oil-in-water emulsions with excipient oil mixtures that have an increased partition coefficient for propofol. We then explored the emulsion stability by measuring size distributions after extended durations of shelf storage and also after freeze-thaw cycling. The effects of oil type, surfactant and salt concentration on emulsion stability were also explored. RESULTS: Small chain oils like ethyl butyrate exhibit high drug partitioning but poor stability, while larger molecules such as soybean oil exhibit lower partitioning but excellent emulsion stability. Emulsions with mixtures of soybean oil and ethyl butyrate are stable for longer than a year, resistant to freeze-thaw cycling, and reduce aqueous drug concentrations of propofol twofold compared to pure soybean oil emulsions. CONCLUSIONS: Oil-in-water emulsions of propofol formulated with mixtures of ethyl butyrate and soybean oil are kinetically stable and significantly reduce the aqueous phase drug concentration making them promising candidates for future propofol therapies.

Production of medium chain fatty acid rich mustard oil using packed bed bioreactor.

A comparative study was done on the production of different medium chain fatty acid (MCFA) rich mustard oil using a stirred tank batchreactor (STBR) and packed bed bio reactor (PBBR) using three commercially available immobilised lipases viz. Thermomyces lanuginosus, Candida antarctica and Rhizomucor meihe. Three different MCFAs capric, caprylic and lauric acids were incorporated in the mustard oil. Reaction parameters, such as substrate molar ratio, reaction temperature and enzyme concentration were standardized in the STBR and maintained in the PBBR. To provide equal time of residence between the substrate and enzyme in both the reactors for the same amount of substrates, the substrate flow rate in the PBBR was maintainedat 0.27 ml/min. Gas liquid chromatography was used to monitor the incorporation of MCFA in mustard oil. The study showed that the PBBR was more efficient than the STBR in the synthesis of structured lipids with less migration of acyl groups. The physico-chemical parameters of the product along with fatty acid composition in all positions and sn-2 positions were also determined.

Enhancing vitamin E bioaccessibility: factors impacting solubilization and hydrolysis of α-tocopherol acetate encapsulated in emulsion-based delivery systems.

Oil-soluble vitamins are often encapsulated within emulsion-based delivery systems to facilitate their incorporation into aqueous-based products. We have examined the influence of carrier oil type and simulated small intestinal fluid (SSIF) composition on the bioaccessibility of emulsified vitamin E using a gastrointestinal model. Oil-in-water emulsions containing vitamin E acetate were prepared using bile salts as emulsifier, and either long chain triacylglycerols (glyceryl trioleate, LCT) or medium chain triacylglycerols (glyceryl trioctanoate, MCT) as carrier oils. The addition of calcium (CaCl2) to the SSIF increased the extent of lipid digestion in LCT-emulsions, but had little impact in MCT-emulsions. The bioaccessibility of vitamin E increased in the presence of calcium and phospholipids (DOPC) in LCT-emulsions, but decreased in MCT-emulsions. The highest bioaccessibility (≈66%) was achieved for LCT-emulsions when the SSIF contained both calcium and phospholipids. The conversion of α-tocopherol acetate to α-tocopherol after in vitro digestion was considerably higher for LCT-emulsions when calcium ions were present in the SSIF, but was not strongly affected by SSIF composition for MCT-emulsions. In general, this research provides important information about the factors influencing the bioaccessibility of emulsified vitamin E, which could be used to design more effective emulsion-based delivery systems for increasing the oral bioavailability of this important bioactive component.

The preparation and evaluation of self-nanoemulsifying systems containing Swietenia oil and an examination of its anti-inflammatory effects.

There is an increasing trend among pharmaceutical industries to use natural bioactive materials as medicinal agents and to use new technologies such as self-nanoemulsifying systems. The solubility and bioavailability of poorly soluble drugs can be enhanced by self-nanoemulsifying systems. Swietenia oil is frequently used because of its antimicrobial, antimutagenic, and anticancer bioactive medical properties. This study was conducted to develop self-nanoemulsifying systems for Swietenia oil that will enhance the anti-inflammatory activity of the oil. The self-emulsifying systems developed for Swietenia oil in this study were constructed using ternary phase diagrams and contained the nonionic surfactants Labrasol(®), Tween 20, Capmul(®), and Labrafil(®). The effect of these surfactants on the formulation was examined. The mean droplet size of Swietenia oil as well as their distribution, appearance, viscosity, and spreading times were studied to find the optimum formula, which contained droplets that were less than 200 nm. The next step was to test the anti-inflammatory properties of the optimum formula using a carrageenan-induced rat paw edema test. The results from this test were compared to the oil solution. Different oil/surfactants mixtures had various emulsification properties that were related to the size of their droplets. Tween 20 is a good surfactant to use in self-emulsifying systems because it produces droplets of nano-size. Mixtures of Capmul/Labrasol at a ratio of 2:1 and Labrafil/Tween 20 at a ratio of 1:2 were able to produce self-nanoemulsifying formulations containing Swietenia oil concentrations that ranged from 20%-50%. Nanoemulsion occurred when the size of the droplets fell below 200 nm with low size distribution (<0.3) after being gently mixed with water. It was found that the hydrophilic/lipophilic balance value affected the ternary phase diagram behavior of Swietenia oil and surfactants. In addition, the anti-inflammatory properties of Swietenia oil were greater in the self-nanoemulsifying systems than in the oil solution.

A self-microemulsifying drug delivery system to overcome intestinal resveratrol toxicity and presystemic metabolism.

A mixed lipid-mixed surfactant self-microemulsifying drug delivery system (SMEDDS) was developed to exploit the health benefits of resveratrol, a Biopharmaceutical Classification System Class 2 natural polyphenol, subject to extensive intestinal presystemic metabolism. SMEDDS with a mixed lipid phase (castor oil/Capmul MCM 1:1) and a mixed surfactant phase (Kolliphor EL/Kolliphor RH 40 1:1) was developed and evaluated for its self-emulsifying properties and in vitro dispersion. The impact of SMEDDS on the permeability properties of resveratrol and its metabolite fluxes through the rat intestine and Caco-2 cells was monitored. The inhibitory effect of selected SMEDDS components on the efflux transporters multidrug resistance-associated protein and P-gp as well as cytotoxicity was assessed on Caco-2 cells. The formulation allowed for high resveratrol loading (122.5 mg/g SMEDDS), excellent self-emulsifying properties, and very rapid release. When formulated in SMEDDS, resveratrol metabolite efflux significantly declined. The formulation (SMEDDS without incorporated resveratrol) and its individual components did not compromise in vitro cell vitality and integrity. Mixed lipid-mixed surfactant SMEDDS is a prospective formulation to improve resveratrol biopharmaceutical, pharmacokinetic, and toxicological properties, leading the way to resveratrol use not only as a supplement but also as a pharmacological drug.

The role of the hydrophobic phase in the unique rheological properties of saponin adsorption layers.

Saponins are a diverse class of natural, plant derived surfactants, with peculiar molecular structure consisting of a hydrophobic scaffold and one or several hydrophilic oligosaccharide chains. Saponins have strong surface activity and are used as natural emulsifiers and foaming agents in food and beverage, pharmaceutical, ore processing, and other industries. Many saponins form adsorption layers at the air-water interface with extremely high surface elasticity and viscosity. The molecular origin of the observed unique interfacial visco-elasticity of saponin adsorption layers is of great interest from both scientific and application viewpoints. In the current study we demonstrate that the hydrophobic phase in contact with water has a very strong effect on the interfacial properties of saponins and that the interfacial elasticity and viscosity of the saponin adsorption layers decrease in the order: air > hexadecane ≫ tricaprylin. The molecular mechanisms behind these trends are analyzed and discussed in the context of the general structure of the surfactant adsorption layers at various nonpolar phase-water interfaces.

The effect of oil type on the aggregation stability of nanostructured lipid carriers.

Second generation lipid systems for the delivery of bioactive compounds have been developed by mixing a liquid carrier oil with a solid lipid to form so-called nanostructured lipid carriers (NLCs). In this study, we investigated the effect of different liquid carrier oils on the crystallization and aggregation behavior of tristearin NLC dispersions. We found that NLC suspension stability was strongly affected by the type and amount of the carrier oil. As the oil concentration was increased, the crystallization and melting temperatures decreased, the polymorphic transformation rate increased, the particles became more spherical, and suspension stability was enhanced. These results suggest that oil trapped within the growing crystal matrix accelerated polymorphic transformation but retarded the large shape change normally associated with the transformation. We also found that considerably less surfactant was necessary to produce stable NLC suspensions than was required to stabilize solid lipid nanoparticle (SLN) suspensions without a carrier oil. Based on preliminary simulation results, we hypothesized that improved NLC suspension stability was attributable to both reduced particle shape change, which created less new surface area to be covered by surfactant, and increased mobility of surfactant molecules, which resulted in available surfactant being more efficient at covering created surface area.