Self-nanoemulsions loaded with dihydromyricetin: Insights to their formulation stability

Fabrication and characterization of dihydromyricetin-loaded microcapsules stabilized by glyceryl monostearate and whey protein-xanthan gum

Dihydromyricetin (DMY) is a lipophilic nutrient with various potential health benefits; however, its poor storage stability and low solubility and bioavailability limit its applications. This study aims to encapsulate DMY in microcapsules by membrane emulsification and freeze-drying methods to overcome these issues. Glyceryl monostearate (GMS, solid lipid) and octyl and decyl glycerate (ODO, liquid lipid) were applied as the inner cores. Whey protein and xanthan gum (XG) were used as wall materials. The prepared microcapsules had an irregular blocky aggregated structure with rough surfaces. All the microcapsules had a DMY loading of 0.85 %-1.1 % and encapsulation efficiency (EE) >85 %. GMS and XG increased the DMY loading and EE. The addition of GMS and an increased XG concentration led to a decrease in the rehydration rate. The in vitro release and digestion studies revealed that GMS and XG controlled the release and digestion of DMY. The chemical stability results indicated that GMS and XG protected DMY against oxidation. An antioxidant capacity study showed that GMS and XG helped DMY in the microcapsules exert antioxidant effects. This research study provides a platform for designing microcapsules with good stability and high bioavailability to deliver lipophilic bioactive compounds.

Sophorolipid-based microemulsion delivery system: Multifaceted enhancement of physicochemical properties of xanthohumol

Xanthohumol (XN) has numerous compelling physiological activities, but the poor solubility and stability severely limit its utilization. Therefore, a microemulsion (ME) delivery system based on biosurfactant sophorolipids (SLs) was established and its improvement on physicochemical properties of XN was investigated. The results showed that the systems increased the solubility of XN by about 4000 times, and its half-life during storage was extended to over 150 days. Partial replacement of Tween 80 with SL did not greatly affect their ability to form O/W subregions (in the high aqueous phase), but further improved the solubilization efficiency, storage stability, and antioxidant properties of XN. In vitro models revealed the release profile of XN from the systems followed non-Fickian diffusion, and the ME structure markedly strengthened its digestive stability and bioaccessibility. These results indicated that SL-based ME systems had great potential as a green solubilization and delivery method for XN and other hydrophobic drugs.

D-α-tocopherol polyethylene glycol 1000 succinate-based microemulsion delivery system: Stability enhancement of physicochemical properties of luteolin

In the present study, D-α-Tocopherol polyethylene glycol 1000 succinate-based self-microemulsifying drug delivery systems (TPGS-SMEDDS) were introduced to enhance the solubility and stability of luteolin. The ternary phase diagrams were constructed to obtain the maximum area of microemulsion and suitable formulations of TPGS-SMEDDS. The particle size distribution and polydispersity index of selected TPGS-SMEDDS were analyzed to be less than 100 nm and 0.4, respectively. The thermodynamic stability results suggested that the TPGS-SMEDDS was stable during the heat-cool and freeze-thaw cycle. Moreover, the TPGS-SMEDDS exhibited excellent encapsulation capacity (51.21 ± 4.39 to 85.71 ± 2.40%) and loading efficiency (61.46 ± 5.27 to 102.86 ± 2.88 mg/g) to luteolin. In addition, the TPGS-SMEDDS showed an admirable vitro release ability with a ratio of more than 88.40 ± 1.14% for luteolin in 24 h. Therefore, TPGS-based SMEDDS might provide an effective role for the oral administration of luteolin and holds promise as a potential delivery for poorly soluble bioactive compounds.

Konjac glucomannan-dihydromyricetin complex improves viscosity and hydration capacity of konjac glucomannan as well as the thermal stability of dihydromyricetin

The nutritional benefits of soluble dietary fiber were mainly attributed to its viscosity and hydration capacity. This study was aimed to investigate the effects of the interaction between konjac glucomannan (KGM) and dihydromyricetin (DMY) on the viscosity and hydration capacity of KGM and the thermal stability of DMY. In contrary to most reports, the addition of DMY to KGM resulted in an increase of viscosity and hydration capacity determined via rheology and nuclear magnetic resonance spectroscopy characterization. Meanwhile the prototype retention of DMY in the presence of heating condition at 60 °C and 100 °C were improved. The radical scavenging capacity of DMY under heating condition was improved at 100 °C via the quantification of ABTS⁺ and DPPH. KGM-DMY complex was a non-covalent compound connected by hydrogen bonds which was characterized with particle size analyses, zeta potential analyses, transmission electron microscopy, infrared spectroscopy, X-ray diffraction, and isothermal titration calorimetry. This study was beneficial to the development of polyphenol-enriched nutrition based on KGM, especially in the aspects of satiety, appetite regulation and glucose regulation.

Injectable redox albumin-based hydrogel with in-situ loaded dihydromyricetin

Albumin is widely used in clinics due to its demonstrated biological safety and functional flexibility. Hydrogels derived from natural albumin possess high moisture retention ability and good biodegradability, making albumin ideal biomaterials compared with synthetic polymers. Herein, by reducing disulfide bonds in bovine serum albumin molecules with glutathione and re-oxidizing the free thiols using dimethyl sulfoxide (DMSO) as additional oxidant, three-dimensional network was assembled, leading to the formation of hydrogel. Meanwhile, DMSO is also an excellent solvent for many drugs, and the hydrophobic drug dihydromyricetin (DMY) can be well dissolved in DMSO. During the crosslinking reaction, DMSO participated in fabricating a porous albumin hydrogel network. At the same time, increased loading of DMY and sustained release of DMY were achieved, improving bioavailability of hydrophobic drug DMY. Rheological test and cytotoxicity assay proved excellent elasticity and biocompatibility of the hydrogel. Self-healing property and narrow-needle injection provided potential application of the hydrogel as biomedical materials. This method for formation hydrogels and in situ loading of drugs may expand to preparing other drug loaded hydrogels and find wide applications.

Effect Of Surfactant Chain Length On Emulsification Dynamics Of Self Emulsifying Formulation Of Poorly Soluble Drug

AIM

In this work the aim was to study the chain length of surfactant on the self emulsifying system of a poorly soluble drug, aceclofenac. The selection of almond oil as a lipid vehicle was done on basis of solubility and compatibility of the vehicle with the drug.

METHODS

The effect of varying chain length of different surfactants of Tween series namely Tween 20, Tween 40, Tween 60 and Tween 80 was evaluated on self emulsifying efficiency by constructing pseudoternary diagrams. PEG-400 was used as co-surfactant in a definite ratio with all the surfactants to minimize their concentration. The best self emulsifying ability was exhibited by Tween 80: PEG-400 combination followed by Tween 60: PEG-400, Tween 40: PEG-400, Tween 20: PEG-400. This observation indicates that as the chain length of Tweens increases their ability to form a good microemulsion increases if same co-surfactant is used.

RESULTS

However it has also been found that the presence of unsaturated bond in Tween 80 provides it an elasticity which supports good intermixing of oil and water and leading to formation of a fine microemulsion. Six different formulations were prepared using combination of almond oil, Tween 80, PEG-400 and the drug aceclofenac.

CONCLUSION

The formulations were subjected to various evaluation parameters such as dispersibility, transmittance, pH, globule size, polydispersibility, zeta potential, viscosity, refractive index and in vitro dissolution. The best formulation was found to have globule size of less than 100 nm, zeta potential of -3.35 ± 0.60 mV which indicates formation of a microemulsion of aceclofenac with good stability.

Optimized preparation of eugenol microcapsules and its effect on hepatic steatosis in HepG2 cells

This study was aimed at evaluating the potential of peach gum (PG) and gelatin in the microencapsulation of eugenol and the intervention of eugenol microcapsules on hepatic steatosis in vitro. Response surface method (RSM) was used to optimize the encapsulation conditions of eugenol microcapsules. The microcapsules were characterized by scanning electron microscopy (SEM), dynamic Light Scattering (DLS), Fourier transform infrared spectroscopy (FT-IR) and release behavior in vitro was determined. The effect of eugenol microcapsules on free fatty acids (FFA) treated hepatocellular cells (HepG₂) cells was evaluated by oil red O staining and intracellular total cholesterol (TC) and triglyceride (TG) determination. The results showed that the optimal encapsulation conditions were as follows: the PG-gelatin ratio was 1.6:1.4, the core-wall ratio was 1.6:1.4, the pH was 4 and the emulsification speed was 9000 r/min. The optimized microcapsules were smooth spherical with a size of about 3.09 ± 0.58 μm and the encapsulation was confirmed by FT-IR. In vitro release behavior showed that eugenol microcapsules could be released stably in a neutral environment for 72 h. Oil red O staining showed that 50 and 100 μM eugenol microcapsules could significantly inhibit the lipid accumulation and reduce the TC and TG in steatotic HepG₂ cells induced by FFA. Therefore, PG and gelatin can be used as excellent carriers for the microencapsulation of volatile compounds in the field of biomedical industry, and eugenol microcapsules is a promising preparation for the treatment of nonalcoholic fatty liver disease (NAFLD).