Nanoemulsions

Fabrication and characterization of nanoemulsions for encapsulation and delivery of vitexin: antioxidant activity, storage stability and in vitro digestibility

BACKGROUND

Nanoemulsions were prepared as an encapsulation and delivery system for vitexin, a poorly water-soluble antioxidant. This study evaluated how the type and concentration of the dispersed oil phase and vitexin loading impacted droplet characteristics and nanoemulsion stability. The influences of storage temperature on antioxidant activity and in vitro gastrointestinal digestion on nanoemulsion stability were also investigated.

RESULTS

Nanoemulsions prepared at different dispersed oil concentrations showed diverse characteristics and stability. Highest stability against droplet aggregation and phase separation with small oil droplets (< 150 nm) was observed for nanoemulsions prepared using 300 g kg^-1 medium-chain triglyceride oil. These nanoemulsions are able to entrap and deliver vitexin with high encapsulation efficiency (88-90%) with no significant effect on emulsion stability. Vitexin-loaded nanoemulsions were stable during storage when refrigerated (4 °C) and at room temperature (25 °C) for up to 45 days with no effect on their antioxidant activity. Significantly delayed lipolysis rate and decreased extent of lipid digestion were observed in vitexin-loaded nanoemulsions.

CONCLUSIONS

Stable vitexin-loaded nanoemulsions were successfully produced by high-pressure homogenization using a mixture of Tween 80 and lecithin as emulsifiers. Vitexin-loaded nanoemulsions stabilized with a mixture of these two emulsifiers were effective in retaining antioxidant activity during storage and protecting vitexin from changes during gastrointestinal digestion. Our results suggested that nanoemulsions were effective vitexin delivery systems for food applications. © 2022 Society of Chemical Industry.

Vitamin D3-Loaded Nanoemulsions as a Potential Drug Delivery System for Autistic Children: Formulation Development, Safety, and Pharmacokinetic Studies

The aim of the current study is the development of a vitamin D₃ (VD3)-loaded nanoemulsion (NE) formulation to improve VD3 oral bioavailability for management of vitamin D inadequacy in autistic children. Eight NE formulations were prepared by high-speed homogenization followed by ultrasonication. Four vegetable oils were employed along with two concentrations of Span 20 as the emulsifier. Glycerol, fructose, and mango flavor were included as viscosity modifier, sweetening, and flavoring agents, respectively. The prepared VD3-loaded NE formulations exhibited high drug content (> 98%), droplet size (DS) ranging from 61.15 to 129.8 nm with narrow size distribution, zeta potential values between - 9.83 and - 19.22 mV, and acceptable pH values (4.59-5.89). Storage stability showed that NE formulations underwent coalescence and phase separation during 6 months at room temperature, whereas at refrigerated conditions, formulations showed slight creaming. The optimum formulation (VD3-NE6) revealed a non-significant DS growth at refrigerated conditions and spherical morphology under transmission electron microscopy. VD3-NE6 did not produce any toxic effects to rats treated orally for 3 months, where normal blood picture and kidney and liver functions were observed compared to control rats. Also, serum calcium, oxidative stress, and apoptosis biomarkers remained within normal levels, indicating the safety of the optimum formulation. Furthermore, evaluation of VD3-NE6 oral bioavailability depicted a significant increase in AUC_0-72 and C_max with decreased T_max compared to plain VD3. The optimum formulation demonstrated improved stability, safety, and oral bioavailability indicating the potential for successful management of vitamin D deficiency in autistic children.

Rationale utilization of phospholipid excipients: a distinctive tool for progressing state of the art in research of emerging drug carriers

Phospholipids have a high degree of biocompatibility and are deemed ideal pharmaceutical excipients in the development of lipid-based drug delivery systems, because of their unique features (permeation, solubility enhancer, emulsion stabilizer, micelle forming agent, and the key excipients in solid dispersions) they can be used in a variety of pharmaceutical drug delivery systems, such as liposomes, phytosomes, solid lipid nanoparticles, etc. The primary usage of phospholipids in a colloidal pharmaceutical formulation is to enhance the drug's bioavailability with low aqueous solubility [i.e. Biopharmaceutical Classification System (BCS) Class II drugs], Membrane penetration (i.e. BCS Class III drugs), drug uptake and release enhancement or modification, protection of sensitive active pharmaceutical ingredients (APIs) from gastrointestinal degradation, a decrease of gastrointestinal adverse effects, and even masking of the bitter taste of orally delivered drugs are other uses. Phospholipid-based colloidal drug products can be tailored to address a wide variety of product requirements, including administration methods, cost, product stability, toxicity, and efficacy. Such formulations that are also a cost-effective method for developing medications for topical, oral, pulmonary, or parenteral administration. The originality of this review work is that we comprehensively evaluated the unique properties and special aspects of phospholipids and summarized how the individual phospholipids can be utilized in various types of lipid-based drug delivery systems, as well as listing newly marketed lipid-based products, patents, and continuing clinical trials of phospholipid-based therapeutic products. This review would be helpful for researchers responsible for formulation development and research into novel colloidal phospholipid-based drug delivery systems.