Hydrophilic-lipophilic Balance Values Research Articles

Preparation, optimization, and testing of biostimulant formulations as stress management tools and foliar applications on brinjal and onion for growth and yield

Not only would the application of biostimulant formulations boost vegetable yields under typical and different biotic stress circumstances, but it will also be user and ecologically friendly. Due to their hydrophobic character and huge molecular volumes, the production of highly stable (~ 2 years shelf-life) emulsifiable concentrate (EC) formulations is the bottleneck of plant growth regulator uses. Gibberellic acid (0.25% EC) and Brassinolide (0.15% EC) were developed using a variety of solvents [solvent naphtha (C9), toluene, dimethyl sulfoxide] and surfactants (calcium alkylbenzene sulfonate, nonylphenol ethoxylate-13). Emulsification (spontaneous), detergency, and quick wetting performance were all outstanding in laboratory adjusted phytohormone formulations (E). Highly stable oil in water emulsions with exceptional compatibility (without phase separation) and outstanding emulsion stability (24 h) have been created using secondary alcohol ethoxylates and sulfonate anionic (5:5), which are affected by the hydrophilic-lipophilic balance (HLB) value (12.52) and type of nonionic and anionic surfactants. The hormone content fluctuation was also estimated to be appropriate using liquid chromatography–tandem mass spectrometry (LC–MS/MS) (5.0%). Single and double dosed applications of 450 and 900 mL ha−1 in brinjal (muktakeshi) and 180 and 360 mL ha−1 in onion (sukhsagar) have significantly improved growth and yields above control (untrated) plants. Gibberellic acid boosted brinjal yields by 37.5%, while Brassinolide raised onion yields by 33.9%. Plant growth regulator formulations that have been thoroughly developed and evaluated might be a big step toward environmentally friendly agricultural production.

Research on the upgrading of bio-oil based on low-carbon alcohol solvents and ultrasonic-emulsification

Effects of the emulsifier type, hydrophilic-lipophilic balance (HLB) value, bio-oil ratio, ultrasonic power density, and ultrasonic time were tested relative to the physicochemical properties and stability of emulsified oils to broaden the use of bio-oil and overcome its defects. The results showed that the turbidity and stabilization times of the emulsified oils reached the maximum values of 184 NTU and 84 min (Span 80 and Tween 80), 191 NTU and 92 min (HLB value of 5), 280 NTU and 92 min (bio-oil ratio of 5%), 191 NTU and 81 min (ultrasonic power density of 0.96 w/mL), 273 NTU and 97 min (ultrasonic time of 20 min), respectively. When the bio-oil to methanol ratio was 1:1, the turbidity value of the emulsified oil reached a maximum value of 664 NTU and the stability time was greater than 24 h. The Fourier transform infrared (FTIR) analysis indicated that the emulsified oil did not delaminate after 30 d, and the uniformity and stability of the emulsified oil were improved.

Study on the chemical structure characterization and emulsification-stripping of heavy oil

The viscosity of heavy oil is of great importance on crude oil recovery, and the intrinsic relationship between the molecular structure of heavy oil and its viscosity is still unclear. To this end, the chemical structure of heavy oil is characterized by Scanning Electron Microscopy (SEM) and Diffusion-ordered Spectroscopy (DOSY). The relationship between the molecular structure and viscosity of heavy oil is revealed. The morphology of molecular aggregates is dominated by spherical particles, vesicles and films, and the corresponding viscosity increases sequentially. DOSY show that the heavy oil molecules rapidly gathered into aggregates with increasing concentrations. If the saturated aggregation concentration (maximum degree of aggregation) is exceeded, the volume of the single aggregate remains generally fixed but its quantity begins to increase. In addition, the structure-activity relationship between chemical agents and emulsification-stripping, including their mechanism of effect are systematically studied by interfacial tension (IFT), emulsification and micromodel experiments. The results show that the hydrophilic-lipophilic balance (HLB) values of surfactants that stabilize the emulsions are between 13.7 and 14.5. There is no obvious consistency between the emulsification effect of the surfactant and its IFT, and the stripping effect depends on its permeation and wetting action on the solid interface. The formation of emulsions in porous media mainly depends on the rotational disturbance and shear fracture of the displacing fluid, and the wettability of the solid surface determines the peeling rate of the oil film. Comparing with the blockage of large-sized emulsions, the migration of small-sized droplets in the channels as a continuous phase contributes more to the enhanced oil recovery.

Surfactant membranes architecture and performance: Effect of HLB value and concentration of non-ionic surfactants

This paper discusses a pioneering work on the effect of hydrophilic-lipophilic balance (HLB) values and non-ionic surfactant concentrations on the performance, architecture i.e. morphology and molecular orientation of polyethersulfone/polyether glycol (PES/PEG 600) for surfactant membrane. PES surfactant membranes were developed through phase inversion fabrication technique with the addition of non-ionic surfactants Triton X-100 (TX100) and Tween 20 (T20) into the polymer solution during formulation. The results of the experimental data conducted showed that 2 wt% increase in the concentration of non -ionic surfactants resulted increased in pure water permeated (PWP) flux and salt solution flux. T20 at 3 wt%, the surfactant membrane reached an highest PWP level of around 1200.67 L/m2 × h while showing an highest flux obtained at 31,692 L/m2 x h. Analysis of membrane structure construction from the morphological results of 3 wt% TX100 membrane having lower HLB value yielded highest rejection at 99.7% and became a booster to produce fine membrane structure, subsequently producing high performance surfactant membrane.

Preparation of Starch Phosphate Microparticle Derived from Cassava Starch

Starch is a vital ingredient that is frequently utilized in the culinary and pharmaceutical industries. However, native starch has drawbacks, namely low solubility and intolerance with extreme pH and temperature treatments. Therefore, the starch needs to be modified. Starch phosphate is one of chemical modification technique for starch that used a cross-linking agent such as sodium trimethaphosphate (STMP), sodium tripolyphosphate (STPP) or phosphate chloride (PCl3). This research aims to prepare the microparticles of modified starch from water in oil microemulsion to be applied as a drug delivery matrix. Starch phosphate was modified with a cross-linking method using sodium trimetaphosphate (STMP). The starch used was Cassava starch. Water in oil microemulsion was made with various surfactant compositions as emulsifiers according to Hydrophilic-Lipophilic Balance (HLB) variations values (4.5; 5.0; 5.5; 6.0) and sonication time 30 minutes. The solubility, swelling, and other physicochemical properties of phosphate starch were investigated. Additionally, the functional group analysis used Fourier Transform Infrared Spectroscopy (FTIR) and size particle analysis was performed using Particle Size Analysis (PSA). The result of the FTIR analysis confirmed that the presence of a phosphate groups in the modified starch has been found. The addition of cosurfactants and sonication treatment affected the characteristics of starch microparticles, the higher the HLB value and the addition of cosurfactants reduced the size of starch microparticles.

Elaboration of essential oil nanoemulsions of Rosemary (Rosmarinus officinalis L.) and its effect on liver injury prevention

To overcome the hydrophobic limitation of the essential oil of rosemary were designed nanoemulsions have desirable composition and properties in order to take advantage of rosemary as a hepatoprotective agent. Response surface methodology (RSM) was used to optimize the conditions for preparing rosemary nanoemulsions. Formulation stability under stress conditions was also evaluated. The aim of this study was to analyze the influence of hydrophilic-lipophilic balance (HLB) value and surfactant: oil ratio on the particle size and polydispersity index (PDI) of rosemary essential oil nanoemulsions and to evaluate the hepatoprotection on liver damage of Wistar rats. Results showed that the experimental data were adequately fitted into a second-order polynomial model with multiple regression coefficients (R2) of 0.968. HLB value had a significant effect on the particle size of the nanoemulsions. The NE with the optimum and stable characteristics was for particle size and PDI around 55 nm and 0.2, respectively, and HLB= 12. The optimum nanoemulsion was orally administered to adult male Wistar rats with thioacetamide (TA)-induced hepatic injury. The results of the in vivo model regarding the analysis of transaminases and liver indicated that nanoemulsified rosemary essential oil confers a hepatoprotective effect on the damaged liver of rats.

Rational Mitomycin Nanocarriers Based on Hydrophobically Functionalized Polyelectrolytes and Poly(lactide-co-glycolide).

Encapsulation of hydrophilic and amphiphilic drugs in appropriate colloidal carrier systems for sustained release is an emerging problem. In general, hydrophobic bioactive substances tend to accumulate in water-immiscible polymeric domains, and the release process is controlled by their low aqueous solubility and limited diffusion from the nanocarrier matrix. Conversely, hydrophilic/amphiphilic drugs are typically water-soluble and insoluble in numerous polymers. Therefore, a core–shell approach—nanocarriers comprising an internal core and external shell microenvironments of different properties—can be exploited for hydrophilic/amphiphilic drugs. To produce colloidally stable poly(lactic-co-glycolic) (PLGA) nanoparticles for mitomycin C (MMC) delivery and controlled release, a unique class of amphiphilic polymers—hydrophobically functionalized polyelectrolytes—were utilized as shell-forming materials, comprising both stabilization via electrostatic repulsive forces and anchoring to the core via hydrophobic interactions. Undoubtedly, the use of these polymeric building blocks for the core–shell approach contributes to the enhancement of the payload chemical stability and sustained release profiles. The studied nanoparticles were prepared via nanoprecipitation of the PLGA polymer and were dissolved in acetone as a good solvent and in an aqueous solution containing hydrophobically functionalized poly(4-styrenesulfonic-co-maleic acid) and poly(acrylic acid) of differing hydrophilic–lipophilic balance values. The type of the hydrophobically functionalized polyelectrolyte (HF-PE) was crucial for the chemical stability of the payload—derivatives of poly(acrylic acid) were found to cause very rapid degradation (hydrolysis) of MMC, in contrast to poly(4-styrenesulfonic-co-maleic acid). The present contribution allowed us to gain crucial information about novel colloidal nanocarrier systems for MMC delivery, especially in the fields of optimal HF-PE concentrations, appropriate core and shell building materials, and the colloidal and chemical stability of the system.

Synthesis of diethanolamine-based amino acid derivatives with symmetric and asymmetric radicals in their hydrophobic domain and potential antimicrobial activity

Objectives. Resistance to antibiotics and other antimicrobial drugs is an acute problem in the world today. Therefore, the chemical and pharmaceutical industries are still in search of new antibacterial agents that can overcome the resistance of pathogenic bacterial strains. To date, it has been established that molecules with antimicrobial activity must have an amphiphilic nature, a small size, one or more positive charges, and the required degree of hydrophobicity, that is, a significant hydrophilic–lipophilic balance (HLB) value. Some examples of such structures are antimicrobial peptides or peptidomimetics. This study aimed to develop a universal scheme for synthesizing several amino acid derivatives based on diethanolamine diesters with symmetric and asymmetric radicals in a hydrophobic block and potential antibacterial activity.Methods. The progression of chemical reactions was analyzed using thin-layer chromatography (TLC) on Sorbfil plates. The obtained compounds were isolated and purified using preparative TLC on Kieselgel (Merck) 60 F254 plates and column chromatography on Merck silica gel 0.040–0.063 mm. The TLC method was used to detect substances using a 3% ninhydrin solution, followed by heating to 70 °C. The structures of the obtained compounds were confirmed by hydrogen-1 nuclear magnetic resonance (1H NMR) spectroscopy on a Bruker WM-300 pulse NMR spectrometer, with hexamethyldisiloxane serving as the internal standard.Results. The HLB values of the diethanolamine derivatives were calculated, and samples were selected for subsequent synthesis. A scheme was developed for preparing amino acid derivatives based on diethanolamine diesters with symmetric and asymmetric radicals in the hydrophobic domain, and five new compounds were synthesized. The hydrophilic blocks of these compounds included residues of amino acids such as glycine, β-alanine, L-ornithine, and L-lysine.Conclusions. The potential antimicrobial activity of the synthesized peptidomimetics was assessed by their HLB values using the ACD/Labs Log P program. New amphiphiles were synthesized using amino acids and diethanolamine, and their structures were confirmed by 1H NMR spectroscopy data. The synthesized compounds were prepared for antibacterial activity analysis.

Evaluation of the Pharmaceutical Properties of Clobetasol Propionate Ointments and Base Stability of the Mixture with Heparinoid Oil Based Creams

Clobetasol propionate ointment (CLPO) formulations have been classified as members of the "strongest" steroidal efficacy group, with eight of these formulations currently marketed in Japan. Evaluations of pharmaceutical properties of each formulation revealed three classification types: droplet dispersion type containing propylene glycol (PG) and surfactant, type with surfactant but not PG, and other types. These rheological properties were diverse, with no correlation found between viscosity and ointment type. However, when CLPO and six types of heparinoid oil-based cream (HPOC) formulation mixtures were stored at 37℃, a liquid layer was observed starting at 24 h for one CLPO formulation in which polyoxyethylene hydrogenated castor oil 40 was used as a surfactant out of the four droplet-dispersion type ointments and two low-viscosity HPOC formulations. In contrast, one other type of CLPO formulation that contained a surfactant with polysorbate 80, but not PG, exhibited a liquid layer for all of HPOC formulations. This suggests that CLPO formulations that contain a surfactant with a high hydrophilic-lipophilic balance value are likely to generate a liquid layer for mixtures containing HPOC formulation. The present results demonstrate that not only the pharmaceutical properties of the eight CLPO formulations differ from one another, but also that the stabilities of HPOC formulation mixtures are significantly different. Therefore, pharmacists need to focus on inactive as well as active pharmaceutical ingredients to select formulations that patients will want to use, in addition to successfully treating their pathological conditions.

Influence of HLB Value of Emulsifier on the Properties of Microcapsules and Self-Healing Properties of Waterborne Coatings

In this paper, self-healing microcapsules were prepared by using melamine–formaldehyde (MF) resin as the wall material and shellac as the core material repairing agent. In order to explore the effect of the four factors (i.e., the HLB value of emulsifier, the type of solvent, the mass ratio of shellac to rosin, and the rate of rotating) on the comprehensive performance of microcapsules, and orthogonal experiments with four factors and three levels were carried out. The results showed that the hydrophilic lipophilic balance (HLB) value of the emulsifier was the most important influencing factor. In order to further explore the relationship between the HLB value of the emulsifier and the morphology of the microcapsules and the coating rate as well as to further optimize the performance of the microcapsules, taking the HLB value of the emulsifier as the single factor variable, single-factor tests were carried out. The results showed that when the HLB value was 12.56, the microcapsules of melamine–formaldehyde resin-coated shellac–rosin mixture had a uniform distribution and high coating rate. In order to explore the self-healing properties of waterborne coatings with microcapsules, the microcapsules prepared by single-factor experiments were mixed into the waterborne coatings at mass ratios of 0%, 3.0%, 6.0%, 9.0%, 12.0%, and 15.0%. It showed that the elongation at break of the waterborne coating with the addition of 3.0% microcapsule at mass fraction was improved, and it had a higher repair rate. This study provides a new research idea for the optimization and characterization of the self-healing properties of waterborne coatings.

Strategies for Improved Stability of Methanol-in-Diesel Emulsions

Abstract This study is motivated by the need to present a robust methodology for preparing stable methanol-in-diesel emulsions for use in compression ignition engines with the specific objective of maximizing the methanol content. Specifically, it involved exploring the feasibility of methanol-in-diesel emulsions with conventional surfactants such as Tween-80 and Span-80 and nonconventional surfactants such as 1-dodecanol, pentanol, and butanol. The hydrophilic–lipophilic balance (HLB) values of the surfactant varied from 7 to 15 to investigate the role of the surfactant HLB on the stability of the macroemulsion. It is observed that the macroemulsion with an HLB value of 10 provides the best stability results. Using surfactant HLB value of 10, three macroemulsions with 10 wt%, 15 wt%, and 20 wt% of methanol were prepared using ultrasonication. However, only the macroemulsion with 10 wt% of methanol was observed to be stable for at least 20 days after preparation. Next, the microemulsions of diesel–methanol were produced by using nonconventional surfactants such as 1-dodecanol, pentanol, and butanol. Among these, 1-dodecanol was found out as the most suitable surfactant owing to its ability to form microemulsions with any mixing ratio of diesel–methanol and its high cetane number (63.6). This study has clearly brought out the strategies for preparing both macro and microemulsions. Overall, the results presented in the current work are expected to aid efforts in adapting compression ignition engines for diesel–methanol fuel blends.

Enzymatic structural modification of monogalactosyldiacylglycerols for potential modulation of hydrophile-lipophile balance

This study aimed to enzymatically prepare structured monogalactosyldiacylglycerols (MGDGs) with different hydrophile-lipophile balance (HLB) values for use as emulsifiers. Acidolysis of Perilla frutescens-derived MGDGs with capric acid (10:0) was conducted to obtain structured MGDGs containing 10:0. Lewatit VP OC 1600-immobilized Rhizomucor miehei lipase was used as the biocatalyst. Structured MGDGs (HLB value = 2.95–7.17) containing 13.0–70.6 mol% 10:0 were obtained from P. frutescens MGDGs (HLB value = 1.93). A quadratic regression equation (R2 = 0.920) to predict the 10:0 content of the structured MGDGs under the given conditions was established using response surface methodology. Using a linear regression equation (R2 = 0.999) to predict the HLB value by 10:0 content, structured MGDGs containing 27.1–54.6 mol% 10:0 were predicted to have an HLB value of 4–6, indicating their potential applicability as hydrophobic emulsifiers. Structured MGDGs with a purity of ∼ 43% w/w were obtained from the reaction products using silica column chromatography.

Contrasting impacts of mixed nonionic surfactant micelles on plant growth in the delivery of fungicide and herbicide

HypothesisNonionic alkyl ethoxylate surfactants are widely used in agrochemicals to facilitate the permeation of systemic herbicides and fungicides across the plant waxy film. Industrial grade surfactants are often highly mixed and how the mixing affects their interactions with pesticides and wax films remains largely unexplored. A better understanding could enable design of mixed nonionic surfactants for herbicides and fungicides to maximize their efficiency and reduce wastage whilst controlling their impact on plant wax films. ExperimentIn this study, nonionic surfactants with general structure n-oxyethylene glycol monododecyl ether (C12En) were used to form surfactant mixtures with the same average ethoxylate numbers but different hydrophilic-lipophilic balance (HLB) values. Their mixed micellar systems were then used to solubilize a herbicide diuron (DN) and a fungicide cyprodinil (CP), followed by plant wax solubilization upon contact with wax films. These processes were monitored by 1H NMR and SANS. FindingPesticide solubilization made surfactant micelles effectively more hydrophobic but subsequent wax dissolution caused pesticide release and the restoration of the micellar amphiphilicity. Nonionic surfactants with lower HLBs form larger nanoaggregates, show enhanced wettability, and have better ability to solubilize and permeate pesticides across the wax film, but may cause significant damage to plant growth. These observations help explain why herbicides applied on weeds would benefit from surfactants with lower HLB values while fungicides require surfactants with HLBs to balance between delivery efficiency and potential phytotoxicity risks.

Preparation and evaluation of agar/maltodextrin-beeswax emulsion films with various hydrophilic-lipophilic balance emulsifiers

The structural and physicochemical properties of agar/maltodextrin-beeswax films in the presence of three emulsifiers, including glycerol monostearate, sodium stearoyl lactylate, and polysorbate 80 were investigated. Scanning electron microscopy revealed that addition of lower hydrophilic-lipophilic balance value emulsifiers produced smaller size and more uniform distribution of beeswax in the film matrix. X-ray diffraction and differential scanning calorimetry indicated that the emulsifiers with lower hydrophilic-lipophilic balance values promoted the compatibility between agar/maltodextrin and beeswax more effectively. The incorporation of different emulsifiers showed diverse impacts on the film network structure and physicochemical properties. Agar/maltodextrin-beeswax-polysorbate 80 film showed maximum stiffness (861.99 MPa). Agar/maltodextrin-beeswax-glycerol monostearate film exhibited the highest tensile strength (26.79 MPa), elongation at break (31.83%), water vapor barrier (7.64 × 10−13 g·m−1·s−1·Pa−1) and oxygen barrier properties (3.82 × 10−17 cm2·s−1·Pa−1), which could be more effective for packaging foods that are prone to oxidize.

Effect of hydrophilic–lipophilic balance values of sucrose esters on cornstarch retrogradation

AbstractBackground and objectivesThe relationship between the different hydrophilic–lipophilic balance (HLB) values of sucrose esters and the retardant effect on the cornstarch retrogradation have not been investigated. The present research was aimed to evaluate the effects of the sucrose esters with different HLB values on the retrogradation properties by analyzing the changes in the crystalline structure and water mobility of cornstarch gels after storage.FindingsAll sucrose ester with HLB value (2–15), especially the HLB 15, could retard the long‐term retrogradation of cornstarch gels. After being stored for the same time, the retrograded cornstarch gels containing sucrose ester of HLB 15 had the lowest hardness, relative crystallinity, and R1047/1022. Compared with the additive‐free cornstarch, the hardness, relative crystallinity, and R1047/1022 of cornstarch with sucrose ester of HLB 15 were significantly decreased by 142 g, 8.66%, and 0.41, respectively, after being stored at 4°C for 7 days.ConclusionsSucrose ester with a high HLB value showed a strong retardant effect on the starch retrogradation.Significance and noveltyThese results suggested that sucrose ester with higher HLB value might be a more effective additive in retarding the retrogradation of cornstarch gels.

Effect of components on the emulsification characteristic of glucose solution emulsified heavy fuel oil

Glucose, which can be obtained from the biomass directly, was added into the heavy fuel oil in the form of an aqueous solution to prepare a novel alternative emulsified fuel. The effects of different components (water, glucose and surfactant) on the droplet size distribution, the stability and the viscosity-temperature characteristics were studied experimentally. Results show that the increases in both the water concentration (0–40v/v%) and the hydrophile-lipophile balance (HLB) value (4.3–14.3) have the negative influence on the stability. By contrast, with the enhanced glucose blend ratio (0–40%), the stability and the homogeneity present the rising trends before they are decreased. It is worth noting that the long-term stability (85 °C, 30 days without separation) along with the minimum mean droplet size can be obtained at the 30% glucose blend ratio. Besides, the long-term stability cannot be not obtained at both surfactant concentration of 1% and 5%. The viscosity of the emulsion with surfactant is reduced in the range of 25–35 °C but increased in the range of 60–95 °C compared with that of emulsion without surfactant. Furthermore, there exists the quite slight change of the viscosity with the addition of glucose.

Determination of required hydrophilic-lipophilic balance of Amesiodendron chinense (Merr.) Hu oil and development of stable cream formulation

Amesiodendron chinense (Merr.) Hu oil is reported to use for the treatment of skin disease by Thai folk medicine. Its hydrophilic-lipophilic balance (HLB) value is very important for developing a stable cream formulation. This study aimed to determine the required hydrophilic-lipophilic balance (rHLB) value of Amesiodendron chinense (Merr.) Hu oil and to develop a stable cream formulation. Herbal cream containing Amesiodendron chinense (Merr.) Hu oil was prepared by phase inversion temperature technique using water, Tween80, and Span60. The first series of 11 emulsions with HLB values ranging from 5.0 to 15.0 and the second series of eight emulsions with a smaller interval in HLB values from 5.0 to 7.8 were prepared. rHLB of coconut oil was also determined for validation of methodology. Creaming index is the established parameter to determine rHLB and to develop stable emulsion. Emulsions with optimum emulsifier concentration resulted in less percentage-creaming index. Utilizing determined rHLB, Amesiodendron chinense (Merr.) Hu cream was formulated and evaluated for different physical parameters including viscosity, color, odor, texture, and pH. Finally, the results showed the rHLB value of coconut oil and Amesiodendron chinense (Merr.) Hu oil was 5.4 and 6.2, respectively. The stable creams were developed with a 3% emulsifier. Physical parameters were found to be consistent over 6 cycles of accelerated stability test under 4 and 45○C. Physical properties of cream evaluation ensure the stability of the developed cream. rHLB value of Amesiodendron chinense (Merr.) Hu oil was exhibited, and the stable creams were successfully formulated by utilizing determined rHLB.

Preparation of Highly Stable Oil-in-Water Emulsions with High Ethanol Content Using Polyglycerol Monofatty Acid Esters as Emulsifiers

Oil-in-water (O/W) emulsions containing ethanol have been used in food, cosmetics, paints, and other applications. However, O/W emulsions with long-term stability are difficult to produce at high ethanol concentrations because the adsorption of the emulsifier at the O/W interface is restricted by ethanol. In this study, to resolve this issue, we prepared ethanol-containing O/W emulsions with high dispersion stability using a series of polyglycerol monofatty acid esters (PGFEs) with different fatty acid chain lengths, which are bio-safe nonionic surfactants, as emulsifiers. First, aqueous PGFE solutions containing 0-50 wt% ethanol were prepared and then O/W emulsions were formed using limonene as the oil phase. When decaglycerol stearic acid ester (DGMS, C18) was used as the emulsifier, an O/W emulsion with fine droplets (~30 nm in size) was successfully obtained at an ethanol concentration of 35 wt%. This emulsion remained stable for more than four weeks, during which no phase separation occurred, indicating its high dispersion stability. Furthermore, aqueous DGMS solutions containing 30-40 wt% ethanol were viscous, and a lamellar liquid crystal phase was observed to be dispersed in these solutions. The formation of this lamellar liquid crystal phase at the O/W interface led to an interfacial film with superior viscoelastic properties. The results suggested that the stability of the emulsions was determined by the balance between the decrease in interfacial tension caused by the addition of ethanol and the density (rigidity) of the DGMS film formed at the O/W interface. Finally, to further improve the dispersion stability of the ethanol-containing O/W-type emulsions, O/W emulsions were prepared using a mixture of two PGFEs with different degrees of glycerol polymerization, that is, systems having different hydrophilic-lipophilic balance values.

Neem oil based nano-emulsion formulation by low energy phase inversion composition method: Characterization and antimicrobial activity

This study aimed to prepare neem oil based nano-emulsion by using the phase inversion composition (PIC) method (low energy) followed by its characterization and assessment for antibacterial effectiveness. Nano-emulsion with droplet size below 200 nm was prepared at 27 °C by stabilizing neem oil-in-water with surfactant blend (Tween 80/Span 80) at a 1:1 vol ratio with hydrophilic-lipophilic balance (HLB) value of 10.7. The single-phase formulation of neem oil nano-emulsion was characterized for droplet size, zeta potential and viscosity. In contrast to raw neem oil and ampicillin antibiotic drug, nano-emulsion formulation showed improved antimicrobial activity against human pathogenic bacteria.

Single versus mixed edge activators in caffeine-loaded transfersomes: physicochemical and cytotoxicity assessment

The performance of transfersomes as nanovesicular systems to enhance the skin permeation of bioactive compounds may be modulated according to their composition of edge activators (EAs). Vesicle size, deformability, and encapsulation efficiency can be altered when using nonionic surfactants as EAs with opposing hydrophilic-lipophilic balance (HLB). Thus, this work aimed to assess the impact on the physicochemical properties and the in vitro cytotoxicity profile of transfersomal formulations composed of single or mixed EAs, with opposing HLB values. Transfersomes made of single or mixed nonionic surfactants (Tween® 80 and/or Span® 80) were prepared in the presence and absence of caffeine, used as a model hydrophilic compound. Single or mixed EAs-containing transfersomes displayed promising physicochemical properties for cutaneous applications and were found to be stable for one month of refrigerated storage. Moreover, all transfersomal formulations were compatible with a keratinocyte cell line upon 24 h treatment. Altogether, these preliminary data suggest that the use of mixed nonionic surfactants as EAs may be further explored to modulate the performance of transfersomes as skin permeation enhancers. Keywords: Vesicular systems, nanotechnology, nonionic surfactants, caffeine