Turbiscan Lab Expert Research Articles

Effect of hydrolyzed polyacrylamide on oil droplet stability in polymer-flooding produced water: variation of oil droplets diameter and oil–water interfacial properties

Hydrolyzed polyacrylamide (HPAM) in polymer flooding leads to stable oil-in-water emulsions, making the oil removal from polymer-flooding produced water (PFPW) more difficult. To elucidate HPAM’s effects on the oil separation performance of conventional physical separation process for PFPW, the stability, and diameter of oil droplets of simulated PFPW were accurately determined using the Turbiscan LAB expert. The results demonstrated that an increase in HPAM’s molecular weight and concentration led to a significant decrease in the diameter of oil droplets in simulated PFPW. When the molecular weight of HPAM increased from 6 to 18 MDa, there was a decrease in the Turbidity Scanning Index (TSI) values from 22.5 to 8.7, along with a significant decline in the diameter of oil droplets from 72.7 to 32.6 µm after a settling period of 40 min. Furthermore, a rise in HPAM concentration inhibited the enlargement of oil droplets. As HPAM concentration increased from 0 to 500 mg/L, the diameter of the oil droplets reduced by 42.1 µm after a 40 min settling period. HPAM's effect on restricting the growth of oil droplets remained relatively constant across oil concentrations ranging from 500 to 2500 mg/L. Moreover, increasing the molecular weight of HPAM from 6 to 18 MDa led to a 41.6% increase in PFPW's viscosity and a 38.9% decrease in oil-water interfacial tension, thereby inhibiting oil droplet coalescence. Our findings provide valuable fundamental guidance for the design of innovative separation methods for PFPW treatment.

Enhancing soil aggregation and acetamiprid adsorption by ecofriendly polysaccharides hydrogel based on Ca2+- amphiphilic sodium alginate

Soil aggregation plays an important role in agricultural production activities. However, the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management, resulting in the loss of water, fertilizers and pesticides in soil. At present, hydrogels have been widely reported to promote the formation of soil aggregation. In this paper, amphiphilic calcium alginate (ASA/Ca2+) was applied to promote the formation of soil aggregation and enhance pesticide retention. Initially, an ASA was obtained through the one-pot Ugi condensation (a four-component green chemical reaction). Then, ASA/Ca2+ hydrogel is prepared by Ca2+ cross-linking. The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer, Confocal Laser Scanning Microscope (CLSM), and Transmission Electron Microscope (TEM). And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics, adsorption isotherms, and leaching. The results shown that the three-dimensional network structure of ASA/Ca2+ hydrogel can promote the formation of soil aggregation. Aggregate durability index (ADI) was 0.55 in the presence of ASA/Ca2+ hydrogel, indicating that amphiphilic hydrogel can enhance the stability of soil aggregation. The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil, and the release of acetamiprid only about 20% in the presence of ASA/Ca2+ hydrogel. These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation. Thus, ASA/Ca2+ hydrogel is likely to improve soil quality, simultaneously it can minimize the mobility of pesticides in the agricultural system.

Carrier Flotation of Low-Rank Coal with Polystyrene

The problem of low-rank coal flotation continues to be a challenge due to the poor hydrophobicity and abundant oxygenated functional groups on particle surfaces. In this study, carrier flotation was used to improve the flotation performance of low-rank coal with polystyrene as a carrier material. Kerosene was used as a collector and played a role in the adhesion of fine low-rank coal to polystyrene due to its hydrophobic properties. The carrier feature of polystyrene was demonstrated by Turbiscan Lab Expert stability analysis and scanning electron microscopy analysis. The flotation experiments revealed that the optimum conditions were: collector dosage 5000 g/t, pulp concentration 40 g/L, and the ratio of low-rank coal to polystyrene 100:10. Under these conditions, the combustible recovery by carrier flotation was obtained as 70.59% when the ash content was 12.32%, which increased by 25.68 points compared with the combustible recovery of conventional flotation under almost the same ash content. The fine coal particles coated the coarse polystyrene particles through hydrophobic interactions between the polystyrene and hydrocarbon chains of the kerosene adsorbed on coal particles. The results suggested that the flotation performance of low-rank coal was significantly improved by carrier flotation with polystyrene, especially for fine particles.

Preparation and characterization of oil-in-water emulsion based on eco-friendly emulsifiers

In current agricultural systems, environment-friendly agrochemicals play essentially important roles in preventing crops from diseases, increasing crop yields and reducing environmental pollution. However, the development of green pesticides with desirable physical properties and specific bioavailability remains a challenging task to date. In this study, a novel class of binary additives of amphiphilic sodium alginate derivative (Ugi-Alg) /alkyl glycoside (APG) as emulsifiers was proposed to improve the stability of pesticide oil-in-water emulsion (EW) and the wettability of solutions on banana leaf surface. Using these emulsifiers, an eco-friendly oil-in-water (O/W) emulsion loaded pesticide has been prepared for pesticide delivery. The effect of Ugi-Alg and APG on emulsion stability was assessed by Turbiscan LabExpert stability analyzer, Optical Microscopy and DHR rotational rheometer. Our results clearly evidenced that the increase of Ugi-Alg concentration effectively enhanced the interfacial layer thickness of emulsion droplets due to hydrophobic interaction, which further significantly improved the stability of emulsion solution. With 3 g/L Ugi-Alg and APG (4 wt%) in the emulsions, the solution showed long-term stability up to 30 d. The effect of Ugi-Alg and APG surfactants on the deposition of pesticide solution was also evaluated on banana leaves. Based on our characterizations, including the surface free energy, the surface tension, the retention ability, the contact angle and the pesticide deposition, we concluded that the mixed surfactants of Ugi-Alg and APG can greatly improve the wettability and adhesion of pesticide solutions on leaf surfaces. This novel platform utilizing both green polymer and non-toxic surfactant for the formation of environment-friendly EW is likely to improve the delivery efficiency of pesticides, minimizing the environmental pollution resulted from the overuse of pesticides in agricultural system.

Pickering emulsions synergistic-stabilized by amphoteric lignin and SiO2 nanoparticles: Stability and pH-responsive mechanism

The pH-responsive O/W Pickering emulsions were stabilized by amphoteric lignin (AML) absorbed with SiO2 nanoparticles via electrostatic interaction. AML was gained by quaternary ammonium modification of alkali lignin, and its structure was characterized by 1H NMR. Fourier transform infrared spectroscopies and Zeta potential measurements were performed to investigate the interaction between AML and SiO2. The formed AML@SiO2 compounds were utilized to prepare Pickering emulsions. The influences of AML concentration and pH on emulsions were studied by rheological measurements and Turbiscan Lab Expert stability index system. The pH-responsive mechanism of Pickering emulsions was investigated by Zeta potential, quartz crystal microbalance with dissipation, atomic force microscopy and three-phase contact angle. The results indicated that at the pH range of 3-4, AML was absorbed on SiO2 to realize the in-situ hydrophobization of SiO2, forming stable Pickering emulsions. When pH was above 4, only a little amount of AML was absorbed on SiO2 due to the strong electrostatic repulsion between them, resulting in unstable emulsions. The emulsions could be cycled at least 5 times between emulsification and demulsification as well as exhibited excellent salt tolerance.

Exploration on the Approaches of Diverse Sedimentations in Polyphenol Solutions: An Integrated Chain of Evidence Based on the Physical Phase, Chemical Profile, and Sediment Elements.

Triphala is a famous herbal formula originated in Asia and is popular in America. Due to the high abundance of polyphenols, its oral liquid is unstable and easy to cause precipitate, which results in the loss of activities. However, complex composition and unclear precipitation mechanism hinders the improvement of stability. In this study, the accumulation of precipitation in the storage and its effect on activity were investigated. Then, an integrated chain of evidence was proposed based on the physical phase, chemical profile, and sediment elements. The results showed that antioxidant activity decreased from IC50 115 to 146 μl before and after 90 days of storage, and the anti-fatigue activity decreased from 30.54 to 28.47 min. Turbiscan Lab Expert observed that particle size increased from 106 to 122 nm, and the turbiscan stability index increased from 0 to 14, which indicated that its stability is continuously decreasing. High performance liquid chromatography (HPLC) fingerprint coupled with multivariate statistical analysis identified that these chemical markers changed significantly, such as gallic acid, catechins, and ellagic acid. Loss of catechins tends to be involved in the formation of phlobaphene precipitation. The fact that the new-born ellagic acid in precipitation (0.47 mg/ml) is significantly higher than that reduced in solution (0.25 mg/ml) indicates that it is not only derived from colloid aging. Microscopic observation combined with energy spectrum analysis further confirmed the existence of the multi-precipitates. The crystalline precipitate is ellagic acid, and the other is phlobaphene. In conclusion, based on the evidence chain analysis, this study revealed a systematic change of the whole polyphenol solution system. It provides a novel perspective to understand the sedimentation formation of polyphenol solution, which is an important theoretical contribution to the preparation of polyphenol solutions.

Study on the stability of heavy crude oil-in-water emulsions stabilized by two different hydrophobic amphiphilic polymers

Emulsification is an important oil recovery mechanism for amphiphilic polymer flooding, with a good viscosity reduction effect for heavy oil. Hence, the comparison study, aimed to elucidate the stabilization mechanism of amphiphilic polymers with single-branched and multi-branched hydrophobic groups, was proposed for the first time. Two amphiphilic polymers with different hydrophobic groups, poly (acrylamide/2-acryloylamino-2-methyl-1-propane sulfonic acid/N, N-dodecyl acrylamide) (PAAD) and poly (acrylamide/2-acryloylamino-2-methyl-1-propane sulfonic acid/N-dodecyl acrylamide) (PAAC), were employed to generate heavy crude oil-in-water emulsion. A laser particle size analyzer and Turbiscan Lab Expert stability analyzer were employed to characterize the stability of emulsions stabilized by the amphiphilic polymers. The results showed that the stability of emulsion stabilized by PAAD (Em-PD) was better than that of emulsion stabilized by PAAC (Em-PC). The particle size of Em-PD ranged from 0.9 μm to 10.5 μm while that of Em-PC ranged from 1.6 μm to 16.5 μm, which indicated that Em-PD showed a smaller average particle size and narrower distribution. It is found that the decline of oil-water interfacial tension is not the key factor for emulsion stability. The multi-branched amphiphilic polymer shows the enhancement of both the viscosity of dispersion medium and the interfacial viscoelasticity, producing the emulsion with stronger stability. The current work shows by designing the molecular structure of amphiphilic polymer to adjust its hydrophobicity can achieve the desired stability of heavy crude oil emulsion which is good for enhanced oil recovery.

Stability mechanism of O/W Pickering emulsions stabilized with regenerated cellulose

The stability and mechanism of O/W Pickering emulsions stabilized with regenerated cellulose were investigated. The Turbiscan Lab Expert Stabilizer, Particle Size Analyser, and Physica MCR301 Rheometer were used. When the concentration of regenerated cellulose increases, the aggregation of regenerated cellulose, emulsion stability and bulk and interfacial viscoelasticity increase as the diameter of the oil droplets decreases. In addition, the emulsions display a typical gel-like characteristic, and the oil-water interfacial shear rheological behaviour slightly differs from that of the O/W Pickering emulsions. This difference can be attributed to the aggregation of regenerated cellulose in the droplet surface under the shear condition. The emulsions exhibit excellent salt resistance at high salt concentrations. Moreover, the regenerated cellulose displays a better temperature resistance than amphiphilic polymer (AP), which is commonly used in oilfields. Hence, commercially available regenerated cellulose can be used as an ideal candidate for enhanced oil recovery.

Preparation and characterization of water-in-oil emulsions of isoprothiolane

Rice blast is a serious disease affecting rice, which causes considerable reduction to its yield. Chemical control plays an important role in controlling this disease. Agricultural aerial spraying is one of the most efficient methods for plant protection over large areas, especially in paddy fields. However, formulations suitable for application by unmanned aerial vehicles (UAVs) are lacking in China. Based on the requirements of aerial spraying special formulations, the solvent and emulsifier were screened to prepare water-in-oil (EO) emulsions of isoprothiolane, and the stabilities of the resulting emulsions were characterized using a Turbiscan LabExpert with a thermostatic system. The physical-chemical properties of the EO emulsions were determined using the respective Collaborative International Pesticides Analytical Council (CIPAC) methods The results indicated that the EO emulsions of isoprothiolane with the advantages of environmental friendly, stabilization, and high efficiency is prepared by the environmentally friendly, high boiling point, heavy aromatic solvent S200 and the polymeric emulsifier A-7. The polymer emulsifier A-7 promotes the stability of the EO emulsions better than the conventional surfactant. The water-in-oil emulsion represented an improved dosage form in terms of pesticide properties: oil as the continuous phase of the EO emulsion has better anti evaporation performance, and the stable EO emulsion can reach the foliage and spread quickly, which can improve the deposition on target. This study provides valuable information for the use of EO emulsions for a wide range of applications, especially in UAVs without dilution.

Formulation and optimization of emulsions based on bitter fennel essential oil and EO/BO block copolymer surfactant

The influence of EO/BO block copolymer surfactant concentration in the range (1–5% (m/m)) and emulsification time on the emulsion stability and droplet size distribution of bitter fennel essential oil-in-water emulsions has been studied.Essential oils are promising material to be used for emulsion formulation with applications in cosmetics, food industry and agrochemicals. In the latter field these emulsions may be used as matrices for pesticides, where essential oils play the role of an eco-friendly solvent.A two-factor central composite design was conducted in order to optimize the emulsion formulation and processing. Emulsion stability has been studied as function of ageing time, by multiple light scattering (Turbiscan Lab-expert, Formulaction) and laser diffraction (Mastersizer X, Malvern). The surface response methodology allowed us to obtain a formulation comprising minimum droplet size and maximum stability by using a single step rotor/stator homogenization process.Creaming turned out to be the main destabilization mechanism. In order to improve emulsion stability the influence of high pressure homogenization (M110P, Microfluidics, MA, USA) and addition of a weighting agent (rosin gum) was studied. Although lower droplet sizes were obtained in both cases (D3,2 were in the range 0.30–0.35μm), emulsions were more unstable maybe due to Ostwald ripening phenomena.

Dual Tumor-Targeting Nanocarrier System for siRNA Delivery Based on pRNA and Modified Chitosan.

Highly specific and efficient delivery of siRNA is still unsatisfactory. Herein, a dual tumor-targeting siRNA delivery system combining pRNA dimers with chitosan nanoparticles (CNPPs) was designed to improve the specificity and efficiency of siRNA delivery. In this dual delivery system, folate-conjugated and PEGylated chitosan nanoparticles encapsulating pRNA dimers were used as the first class of delivery system and would selectively deliver intact pRNA dimers near or into target cells. pRNA dimers simultaneously carrying siRNA and targeting aptamer, the second class of delivery system, would specifically deliver siRNA into the target cells via aptamer-mediated endocytosis or proper particle size. To certify the delivering efficiency of this dual system, CNPPs, pRNA dimers alone, chitosan nanoparticles containing siRNA with folate conjugation and PEGylation (CNPS), and chitosan nanoparticles containing pRNA dimers alone (CN) were first prepared. Then, we observed that treatment with CNPPs resulted in increased cellular uptake, higher cell apoptosis, stronger cell cytotoxicity, and more efficacious gene silencing compared to the other three formulations. Higher accumulation of siRNA in the tumor site, stronger tumor inhibition, and longer circulating time were also observed with CNPPs compared to other formulations. In conclusion, this dual nanocarrier system showed high targeting and favorable therapeutic efficacy both in vitro and in vivo. Thereby, a new approach is provided in this study for specific and efficient delivery of siRNA, which lays a foundation for the development of pRNA hexamers, which can simultaneously carry six different substances.

Dispersion of silicon carbide in poly alpha olefins-6 and trimethylopropane trioleate

In this paper, the dispersion behavior and interactions among SiC particles, dispersant and solvent were investigated. A hyperdispersant (Tech-5080) was adopted to study the stability mechanism in poly alpha olefins-6 (PAO6)/trimethylopropane trioleate (TMPTO) solvent system. Optical microscope and SEM images were used to assess the degree of dispersion. FT-IR analysis results showed that the dispersant were adsorbed onto the particle surface by hydrogen bonding. The stability measurements were studied by Turbiscan Labexpert and the size distribution was examined by Zetasizer Nano ZS to evaluate the effect of dispersant content on the stabilization of SiC suspension. A model was illustrated to explain the changing process of SiC particles in the solvent, which brings new insight into the dispersion phenomenon. Results showed that well dispersed SiC slurry could be developed with 50vol% PAO6 as solvent and using 0.5wt% Tech-5080 as the dispersant.

The Influence of Maltodextrin on the Physicochemical Properties and Stabilization of Beta-carotene Emulsions.

Beta-carotene is important for fortification of nutritional products while its application is limited by instability. The influence of maltodextrin (MDX) on physicochemical properties and stability of beta-carotene emulsions stabilized by sodium caseinate (SC) was investigated. The emulsions were characterized by dynamic light scattering (DLS), laser diffraction (LD), transmission electron microscopy (TEM), rheometer, and turbiscan lab expert. The effects of pH, ionic strength, and freeze-thaw on stability of emulsions were observed. The emulsions could tolerate up to 2mol/L NaCl or 10mmol/L CaCl2 and showed Newtonian behavior. The droplet diameter, polydispersity index, and zeta-potential did not change obviously after 3months storage at 4°C in dark conditions. The emulsions with MDX showed excellent freeze-thaw stability and gave favorite protection for beta-carotene. The retention ratio of beta-carotene in the emulsions with MDX was above 92.1% after 3months storage while that in the one without MDX was only 62.7%. The study may provide a promising strategy to improve stability of sensitive nutraceuticals without adding synthetic antioxidants. The findings obtained could provide fundamental basis for rational design of emulsion delivery systems when freeze-thawing is required during manufacturing process or storage period.

Biorefinery Lignosulfonates from Sulfite-Pretreated Softwoods as Dispersant for Graphite

Two biorefinery lignosulfonates (LSs), Ca-LS-DF and Na-LS-LP, were, respectively, isolated from pilot-scale sulfite-pretreated spent liquor of lodgepole pine and fermentation residue of Douglas-fir harvest forest residue. The molecular weights of Na-LS-LP and Ca-LS-DF were approximately 9 000 and 11 000 Da, respectively. The two LSs were applied as dispersant for graphite in aqueous suspensions. The dispersion stability was evaluated by a scanning electron microscope and Turbiscan Lab Expert. LS performance in modifying graphite was better than that of a commercial dispersant Reax-85A as indicated by the Turbiscan TSI values, zeta potential of suspension particles, and SEM imaging. The practical importance of this study lies in the fact that the pilot-scale sulfite pretreatments that produced the two LSs also produced excellent bioethanol yields at high titer without detoxification and washing, suggesting the LSs are a true value-added coproduct for high yield biofuel production.

Long Term Stability Evaluation of Prostacyclin Released from Biomedical Device through Turbiscan Lab Expert.

Therapeutic guidelines indicate prostacyclin as the first line of treatment in inflammation and vascular diseases. Prostacyclins prevent formation of the platelet plug involved in primary hemostasis by inhibiting platelet activation and, combined with thromboxane, are effective vasodilators in vascular damage.Trans-Atlantic Inter-Society Consensus Document on Management of Peripheral Arterial Disease II guidelines indicates prostacyclins; in particular, Iloprost, as the first therapeutic option for treating peripheral arterial disease. However, therapeutic efficacy of Iloprost has witnessed several drawbacks that have occurred in patients receiving repeated weekly administration of the drug by intravenous infusions. Adverse reactions arose under perfusion with Iloprost for 6 h and patient compliance was drastically decreased. Biomedical devices could provide a suitable alternative to overcome these drawbacks. In particular, elastomeric pumps, filled with Iloprost isotonic solution, could slowly release the drug, thus decreasing its side effects, representing a valid alternative to hospitalization of patients affected by peripheral arterial disease. However, the home therapy treatment of patients requires long-term stability of Iloprost in solution-loaded elastomeric pumps.The aim of this work was to investigate the long-term stability of Iloprost isotonic solution in biomedical devices using Turbiscan technology. Turbiscan Lab Expert (L’Union, France) predicts the long-term stability of suspensions, emulsions and colloidal formulations by measuring backscattering and transmission of particulates dispersed in solution. The formulations were evaluated by measuring the variation of physical-chemical properties of colloids and suspensions as a function of backscattering and transmission modifications. In addition, the release profile of Iloprost isotonic solution from the biomedical device was evaluated.

Influence of carboxylic group content on the solution behavior of carboxymethylated lignin (CML) in water

Abstract Carboxymethylated lignin (CML) is well suited as a dispersant or natural adsorbent applied in ceramics, gypsum paste, graphite suspension, and water treatment. In this paper, the effects of COOH content in CML on its behavior in water and the dispersion stability of aqueous graphite suspension has been investigated by means of viscosimetry, surface tension measurement, fluorescence spectrometry, dynamic light scattering (DLS), Turbiscan Lab Expert (TLE) stability analysis, and ζ potential measurement. Viscosimetry clearly revealed the polyelectrolyte effect in diluted aqueous solution of CML. With a higher COOH content of CML, the surface tension of water is reduced. Moreover, the aggregation behavior of CML was strengthened with increasing COOH content, leading to a more compact molecular structure of the aggregates. Based on the results, an aggregation model was proposed to illustrate the variations in the solution behavior of CML with different COOH contents at various concentrations. The dispersion stability of aqueous graphite suspension was improved by adding CML with high COOH content.

Study of the solution behavior of β-cyclodextrin amphiphilic polymer inclusion complex and the stability of its O/W emulsion

A supramolecular recognition system was constructed based on the host–guest interaction with water-soluble β-cyclodextrinpolymer-P(AM/A-β-CD/NaA) as the host polymer and hydrophobically modified polyacrylamide-P(AM/C18/NaA) as the guest one. The guest polymer contains a small amount of hydrophobic octadecyl groups. High viscosity enhancement was observed when P(AM/A-β-CD/NaA) was added to P(AM/C18/NaA) solution, the concentration of P(AM/C18/NaA) was under the critical aggregation concentrations (CAC), as a result of the polymer inclusion association. The influences of salt concentration, shearing, pH values and temperature on the viscosity of mixture solution were also studied. O/W crude oil emulsion stabilized by the complex was prepared. A laser particle size analyzer and Turbiscan Lab Expert stability analyzer were employed to study their stability. The results indicated that mixture emulsion became more stable than the single amphiphilic polymer's. This is because that the net structure of elastic polymer in the continuous phase has the ability to hold oil droplets at the low concentration of P(AM/C18/NaA). The stability mechanism of O/W emulsion was indicated by three-stage visual rheological method. In this paper, the stability of inclusion complex is discussed, and the mechanism of the enhanced oil emulsification is further explored.

Ammonium glycyrrhizinate-loaded niosomes as a potential nanotherapeutic system for anti-inflammatory activity in murine models.

BackgroundLiquorice extracts demonstrate therapeutic efficacy in treating dermatitis, eczema, and psoriasis when compared with corticosteroids. In this work, nonionic surfactant vesicles (niosomes, NSVs) containing polysorbate 20 (Tween 20), cholesterol, and cholesteryl hemisuccinate at different molar concentrations were used to prepare monoammonium glycyrrhizinate (AG)-loaded NSVs. The anti-inflammatory properties of AG-loaded NSVs were investigated in murine models.MethodsThe physicochemical properties of the NSVs were characterized using dynamic light scattering. The fluidity of the lipid bilayer was evaluated by measuring the fluorescence intensity of diphenylhexatriene. The drug entrapment efficiency of AG was assessed using high-performance liquid chromatography. The physicochemical stability of the NSVs was evaluated as a function of time using dynamic light scattering combined with Turbiscan Lab® Expert analysis. Serum stability was determined by incubating the NSVs with 10% v/v fetal bovine serum. The cytotoxic effects of the NSVs were investigated in human dermal fibroblasts using the Trypan blue dye exclusion assay (for cell mortality) and an MTT assay (for cell viability). Release profiles for the AG-loaded NSVs were studied in vitro using cellulose membranes. NSVs showing the most desirable physicochemical properties were selected to test for in vivo anti-inflammatory activity in murine models. The anti-inflammatory activity of the NSVs was investigated by measuring edema and nociception in mice stimulated with chemical agents.ResultsNSVs showed favorable physicochemical properties for in vitro and in vivo administration. In addition, they demonstrated long-term stability based on Turbiscan Lab Expert analysis. The membrane fluidity of the NSVs was not affected by self-assembling of the surfactants into colloidal structures. Fluorescence anisotropy was found to be independent of the molar ratios of cholesteryl hemisuccinate and/or cholesterol during preparation of the NSVs. The anti-inflammatory AG drug showed no effect on the stability of the NSVs. In vivo experiments demonstrated that AG-loaded NSVs decreased edema and nociceptive responses when compared with AG alone and empty NSVs. In vitro and in vivo results demonstrated that pH sensitive and neutral NSVs show no statistical significant difference.ConclusionNSVs were nontoxic and showed features favorable for potential administration in vivo. In addition, neutral NSVs showed signs of increased anti-inflammatory and antinociceptive responses when compared with AG.

Nanodesign of olein vesicles for the topical delivery of the antioxidant resveratrol

The ex-vivo percutaneous absorption of the natural antioxidant resveratrol in liposomes and niosomes was investigated. The influence of vesicle composition on their physicochemical properties and stability was evaluated. Liposomes containing resveratrol were formulated using soy phosphatidylcholine (Phospholipon90G). Innovative niosomes were formulated using mono- or diglycerides: glycerol monooleate (Peceol) and polyglyceryl-3 dioleate (Plurol OleiqueCC), respectively, two suitable skin-compatible oleins used in pharmaceutical formulations as penetration enhancers. Small, negatively charged vesicles with a mean size of approximately 200 nm were prepared. The accelerated stability of vesicles was evaluated using Turbiscan Lab Expert, and the bilayer deformability was also assessed. Ex-vivo transdermal experiments were carried out in Franz diffusion cells, on newborn pig skin, to study the influence of the different vesicle formulations on resveratrol skin delivery. Results indicated a high cutaneous accumulation and a low transdermal delivery of resveratrol, especially when Peceol niosomes were used. Overall, niosomes formulated with Plurol oleique or Peceol showed a better behaviour than liposomes in the cutaneous delivery of resveratrol.

Stability of Colloidal Silica Modified by Macromolecular Polyacrylic Acid (PAA) – Application of Turbidymetry Method

The effect of anionic polyacrlic acid (PAA) adsorption on fumed silica (SiO2) surface on suspension stability was studied. The turbidymetry method was applied to monitor the changes in the suspension stability (using apparatus Turbiscan LabExpert with cooling module TLAb Cooler). PAA macromolecules contain dissociable carboxyl groups, therefore, all measurements were carried out at three pH values: 3, 6 and 9. Analysis of obtained transmission and backscattering curves and Turbiscan Stability Indexes (TSI) allowed determination of the most probable mechanism of the stability of the studied systems. The PAA adsorption has the greatest impact on the silica suspension stability at pH 3 (significant improvement of its stability). On the other hand, the presence of polyacrylic acid at pH 6 causes a noticeable deterioration of system stability conditions. At pH 9, polymer minimally influences the stability of SiO2 suspension.