Thuy Chinh Nguyen

Silymarin has been facing several challenges which reduce its therapeutic effect, mainly low solubility and poor bioavailability. This study aimed to develop and comparatively evaluate the stability and antioxidant activity of an oil-in-water (O/W) nanoemulsion to encapsulate silymarin, formulated with two distinct natural carriers: grape seed oil (GSO) and Sacha inchi seed oil (SIO). To achieve a stable system, Tween 80 and Poloxamer 407 (F-127) were employed as the primary surfactant and co-stabilizer, respectively, using the phase inversion composition technique at a surfactant-to-oil mass ratio of 1.1:1 (w/w). The resulting optimized formulations demonstrated favorable physicochemical characteristics, including droplet sizes between 300 and 700 nm and PDI values from 0.2 to 0.5. High electrostatic stability was confirmed by negative zeta potentials exceeding −30 mV. The formulations with a lower silymarin content exhibited higher entrapment efficiency compared to those with a higher drug loading. While Fourier transform—infrared and microscopic analyses verified successful encapsulation and uniform morphology, DPPH assays indicated that the nanoemulsions maintained potent radical scavenging activity (52.88 and 13.82%), although they are lower than that of the free silymarin (92.08%) due to the protective encapsulation. Additionally, the use of GSO and SIO significantly enhanced oxidative stability, as reflected by low peroxide levels. These findings highlight SIO as a highly effective and promising platform for the advanced delivery of silymarin, which can be further formulated into popular and convenient dosage forms such as soft gel capsules or nanoemulgels.

This study reports the fabrication of cerium(III) nitrate-loaded polycaprolactone (PCL) microparticles via a water-in-oil-in-water (W/O/W) double emulsion method, utilizing Sapindus saponaria L. extract as a natural, eco-friendly surfactant. The salt-to-polymer ratio significantly influenced the encapsulation process, with the PC75 formulation achieving an optimal encapsulation efficiency of 26.83%. Dynamic light scattering and zeta potential measurements showed that the microparticles (PC50 and PC75) possessed nanoscale dimensions (280–310 nm) and high colloidal stability (zeta potential < -30 mV). FESEM and EDX characterizations revealed a spherical morphology with a core-shell architecture, while FTIR and XRD analyses verified that the cerium nitrate was successfully embedded within the PCL matrix without altering the polymer's semicrystalline structure. These results demonstrate that the synthesized PCL microparticles, stabilized by a plant-derived surfactant, serve as promising candidates for the development of sustainable, controlled-release additives in anti-corrosion coating applications.

Azelaic acid (AzA) is widely used to treat acne, eczema, melasma, and uneven skin tone. However, the AzA has low solubility and poor skin penetration, so it often requires high doses to achieve the desired therapeutic effect. In this study, the AzA was prepared in the nanoemulsion form using grapeseed oil as an oil phase, distilled water as a water phase, and Tween 20 as a surfactant. A pseudo-ternary phase diagram was built to find the suitable range of components in the nanoemulsion. The composition of the nanoemulsion was optimized by response surface methodology (RSM) with a Box-Behnken design (BBD). The optimal conditions were found to be an oil weight percentage of 10.71 %, a water weight percentage of 56.62 %, and a Tween 20 surfactant percentage of 21.28 %. Under the optimal conditions, the mean droplet size (MDS) of the nanoemulsion reached 152.2 ± 2.7 nm, close to the predicted value of 148.908 nm. Additionally, the functional groups and ultra-violet absorption of the nanoemulsion were assessed by infrared and ultra-violet spectroscopy. The stability of the nanoemulsion versus time was also evaluated. Moreover, the inhibition activity against Bacillus cereus- a gram-positive bacterium - of the nanoemulsion was tested and discussed.

In this study, porous calcium silicate (CaSiO3) materials were synthesized via a sol-gel method using different concentrations of the nonionic surfactant P123 (10 wt.%, 20 wt.%, and 30 wt.%) as structure-directing agents. The effect of P123 content on the textural properties of the resulting materials was systematically investigated. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and nitrogen adsorption-desorption analysis (BET/BJH) were employed to characterize their structural and morphological features. The results indicate that the sample synthesized with 10 wt.%) P123 (Ca10) exhibited the highest surface area (117.3 m2/g) and well-developed mesoporous structure. Increasing P123 content to 20 wt.%) (Ca20) enhanced pore connectivity and cumulative pore volume, while excessive surfactant (30 wt.%), Ca30) led to structural collapse, resulting in decreased surface area and reduced mesoporosity. These findings highlight the importance of controlling the surfactant content to optimize the porosity of calcium silicate for potential applications in drug delivery, adsorption, and catalysis.

In recent years, emulsion-derived microparticles have been applied widely in drug delivery and controlled drug release, especially for those with low solubility in water. Optimizing the ratio of components in a drug-loaded emulsion system is crucial, as it dictates the stability and drug release control of the final product. In this paper, the microparticle system obtained by the emulsion method chosen to study was prepared from poly(caprolactone) (PCL), xanthan gum (XG), and Tween 80 for loading chrysophanol (CHR), as a poorly water-soluble model drug. The ratio of components was surveyed to find the optimal composition for the system stability and droplet size. The optimized emulsion system was loaded with varied drug concentrations and then sedimented, washed, and dried to form solid PCL/XG/CHR (PXC) microparticles. The solid particles were characterized by field emission scanning electron microscopy, ζ-potential and size distribution, infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction analysis. Additionally, physicochemical and pharmacological properties of these emulsion-derived microparticles have also been studied. The CHR structure was changed from crystalline to amorphous when it was loaded in these microparticles. The CHR release process from these particles is also sensitive to pH and can be controlled by the interaction of the drug with polymer matrices. The CHR release mechanism from PXC particles in simulated body fluids is also proposed. Emulsion-derived microparticles containing CHR (PXC1) with high stability, good drug release profile, nontoxicity, and biologically activity have the potential for biomedicine applications.

This study presents a green synthesis of TiO ₂ /Ag nanocomposite materials using extract from Eucalyptus globulus Labill leaves and poly(vinyl alcohol), with dual applications in grape preservation and photocatalytic dye treatment.