Phase behaviors and curcumin encapsulation performance of Gemini surfactant microemulsion

Quality-by-design-based microemulsion of disulfiram for repurposing in melanoma and breast cancer therapy

Aim: The current study aims to develop and optimize microemulsions (ME) through Quality-by-Design (QbD) approach to improve the aqueous solubility and dissolution of poorly water-soluble drug disulfiram (DSF) for repurposing in melanoma and breast cancer therapy. Materials & methods: The ME was formulated using Cinnamon oil & Tween® 80, statistically optimized using a D-optimal mixture design-based QbD approach to develop the best ME with low vesicular size (Zavg) and polydispersity index (PDI). Results: The DSF-loaded optimized stable ME showed enhanced dissolution, in-vitro cytotoxicity and improved cellular uptake in B16F10 and MCF-7 cell lines compared with their unformulated free DSF. Conclusion: Our investigations suggested the potential of the statistically designed DSF-loaded optimized ME for repurposing melanoma and breast cancer therapy.

Redox-responsive microemulsion: Fabrication and application to curcumin encapsulation

HYPOTHESIS

Stimulus-responsive microemulsions have aroused significant attention because of their versatile and reversible switchability between stable and unstable states. However, most stimuli-responsive microemulsions are based on stimuli-responsive surfactants. We posit that the change in the hydrophilicity of a selenium-containing alcohol triggered by a mild redox reaction could also influence the stability of microemulsions and provide a new nanoplatform for the delivery of bioactive substances.

EXPERIMENTS

A selenium-containing diol (3,3'-selenobis(propan-1-ol), PSeP) was designed and used as a co-surfactant in a microemulsion with ethoxylated hydrogenated castor oil (HCO40), diethylene glycol monohexyl ether (DGME), 2-n-octyl-1-dodecanol (ODD) and water. The redox-induced transition in PSeP was characterized by ¹H NMR, ⁷⁷Se NMR, and MS. The redox-responsiveness of the ODD/HCO40/DGME/PSeP/water microemulsion was investigated through determination of a pseudo-ternary phase diagram, analysis by dynamic light scattering, and electrical conductivity, and its encapsulation performance was evaluated by determination of the solubility, stability, antioxidant activity, and skin penetrability of encapsulated curcumin.

FINDINGS

The redox conversion of PSeP enabled efficient switching of ODD/HCO40/DGME/PSeP/water microemulsions. Addition of oxidant (H₂O₂), oxidized PSeP into more hydrophilic PSeP-Ox (selenoxide), disrupting the emulsifying capacity of the combination of HCO40/DGME/PSeP, markedly reducing the monophasic microemulsion region in the phase diagram, and inducing phase separation in some formulations. Addition of reductant (N₂H₄·H₂O), reduced PSeP-Ox and restored the emulsifying capacity of the combination of HCO40/DGME/PSeP. In addition, PSeP-based microemulsions can significantly enhance the solubility in oil (by 23 times), stability, antioxidant capacity (DPPH∙ radical scavenging by 91.74 %), and skin penetrability of curcumin, showing clear potential for encapsulation and delivery of curcumin and other bioactive substances.

Fermented Plant Beverages Stabilized with Microemulsion: Confirmation of Probiotic Properties and Antioxidant Activity

The purpose of this study was to experimentally confirm the probiotic properties and antioxidant activity of plant fermented beverages stabilized with microemulsion. The object of the study were beverages obtained from hemp seeds and fermented with Bifidobacterium longum. To stabilize the plant base, the microemulsion with a bioactive substance (curcumin) was introduced with simultaneous ultrasound treatment. A significant increase in the viscosity of beverages with microcellulose-stabilized microemulsion was noted. Non-fermented plant beverages are characterized by their smaller diameter and distribution of particles in the micro-range, from 0.81 to 6.5 µm. When Twin-stabilized microemulsion was added to beverages, a monodisperse distribution of particles sufficiently small in diameter was observed. A significant increase of 29.4–33.6% in the antioxidant activity of plant beverages stabilized by ME with curcumin was established. A maximum concentration of flavonoids was noted in non-fermented plant beverages containing microemulsion. The results of this study proved the possibility of obtaining fermented plant beverages with identified probiotic and antioxidant properties. A positive effect of stabilizing with a microemulsion loaded with biologically active components on the development of probiotic microorganism cultures in the system of fermented plant products and the formation of their antioxidant activity was established.

Microfluidic preparation of a novel phoxim nanoemulsion pesticide against Spodoptera litura

With continuous development of pesticide dosage forms, emulsifiable concentrates using large amounts of organic solvents are gradually obsoleted. Nanoemulsions with high water content have been developed and the preparation processes also evolved, but these processes still exist some problems, such as poor controllability and high energy consumption. Microfluidic is a controllable nanoemulsion preparation system which mainly applied to pharmaceutical synthesis. In this study, the pesticide phoxim nanoemulsion was prepared by microfluidic technology. The optimized formulation of phoxim nanoemulsion was composed of Tween 80 and pesticide emulsifier 500 as surfactant, hexyl acetate as oil, and n-propanol as co-surfactant. Moreover, when the flow rates of water and oil in the microfluidic system were adjusted to 5 μL/min and 20 μL/min, phoxim nanoemulsion was obtained with a cloud point/boiling point of 109 °C, a particle size of 21.5 ± 0.8 nm and a potential value of - 18.7 ± 0.6 mV. Furthermore, the nanoemulsion had a rapid release effect in vitro which could be fitted by the Ritger-Peppas model. The feeding toxicity of the phoxim nanoemulsion was higher than that of commercial formulation while the contact killing effect was higher than that of the active ingredient. Therefore, pesticide dosage was reduced and the insecticidal effect was enhanced by using phoxim nanoemulsions. These results also confirm the potential of microfluidics as a green process to produce pesticide nanoemulsions.

Microemulsion Delivery System Improves Cellular Uptake of Genipin and Its Protective Effect against Aβ1-42-Induced PC12 Cell Cytotoxicity

Genipin has attracted much attention for its hepatoprotective, anti-inflammatory, and neuroprotection activities. However, poor water solubility and active chemical properties limit its application in food and pharmaceutical industries. This article aimed to develop a lipid-based microemulsion delivery system to improve the stability and bioavailability of genipin. The excipients for a genipin microemulsion (GME) preparation were screened and a pseudo-ternary phase diagram was established. The droplet size (DS), zeta potential (ZP), polydispersity index (PDI), physical and simulated gastrointestinal digestion stability, and in vitro drug release properties were characterized. Finally, the effect of the microemulsion on its cellular uptake by Caco-2 cells and the protective effect on PC12 cells were investigated. The prepared GME had a transparent appearance with a DS of 16.17 ± 0.27 nm, ZP of −8.11 ± 0.77 mV, and PDI of 0.183 ± 0.013. It exhibited good temperature, pH, ionic strength, and simulated gastrointestinal digestion stability. The in vitro release and cellular uptake data showed that the GME had a lower release rate and better bioavailability compared with that of free genipin. Interestingly, the GME showed a significantly better protective effect against amyloid-β (Aβ1-42)-induced PC12 cell cytotoxicity than that of the unencapsulated genipin. These findings suggest that the lipid-based microemulsion delivery system could serve as a promising approach to improve the application of genipin.

Exploration of the Microstructure and Rheological Properties of Sodium Alginate-Pectin-Whey Protein Isolate Stabilized Β-Carotene Emulsions: To Improve Stability and Achieve Gastrointestinal Sustained Release

Sodium alginate (SA)-pectin (PEC)-whey protein isolate (WPI) complexes were used as an emulsifier to prepare β-carotene emulsions, and the encapsulation efficiency for β-carotene was up to 93.08%. The confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) images showed that the SA-PEC-WPI emulsion had a compact network structure. The SA-PEC-WPI emulsion exhibited shear-thinning behavior and was in a semi-dilute or weak network state. The SA-PEC-WPI stabilized β-carotene emulsion had better thermal, physical and chemical stability. A small amount of β-carotene (19.46 ± 1.33%) was released from SA-PEC-WPI stabilized β-carotene emulsion in simulated gastric digestion, while a large amount of β-carotene (90.33 ± 1.58%) was released in simulated intestinal digestion. Fourier transform infrared (FTIR) experiments indicated that the formation of SA-PEC-WPI stabilized β-carotene emulsion was attributed to the electrostatic and hydrogen bonding interactions between WPI and SA or PEC, and the hydrophobic interactions between β-carotene and WPI. These results can facilitate the design of polysaccharide-protein stabilized emulsions with high encapsulation efficiency and stability for nutraceutical delivery in food and supplement products.

Novel Gel Microemulsion as Topical Drug Delivery System for Curcumin in Dermatocosmetics

Gel microemulsion combines the advantages of the microemulsion, which can encapsulate, protect and deliver large quantities of active ingredients, and the gel, which is so appreciated in the cosmetic industry. This study aimed to develop and characterize new gel microemulsions suitable for topical cosmetic applications, using grape seed oil as the oily phase, which is often employed in pharmaceuticals, especially in cosmetics. The optimized microemulsion was formulated using Tween 80 and Plurol^® Diisostearique CG as a surfactant mix and ethanol as a co-solvent. Three different water-soluble polymers were selected in order to increase the viscosity of the microemulsion: Carbopol^® 980 NF, chitosan, and sodium hyaluronate salt. All used ingredients are safe, biocompatible and biodegradable. Curcumin was chosen as a model drug. The obtained systems were physico-chemically characterized by means of electrical conductivity, dynamic light scattering, polarized microscopy and rheometric measurements. Evaluation of the cytotoxicity was accomplished by MTT assay. In the final phase of the study, the release behavior of Curcumin from the optimized microemulsion and two gel microemulsions was evaluated. Additionally, mathematical models were applied to establish the kinetic release mechanism. The obtained gel microemulsions could be effective systems for incorporation and controlled release of the hydrophobic active ingredients.