Enhancing the Stability of Lipid Nanoparticle Systems by Sonication during the Cooling Step and Controlling the Liquid Oil Content

Abstract

Aggregation of unstable particles in water limits the application of lipid nanoparticle (LNP) systems to foods despite the capability to encapsulate lipophilic bioactive components. This study exploits a preparation process that can reduce the aggregation of LNPs. Sonication during the cooling step (postsonication) for 4, 5, or 6 min was applied to increase the covering effect of Tween 20 on the particle. Additionally, LNPs were prepared using fully hydrogenated canola oil (FHCO) blended with 0-30 wt % liquid canola oil (LCO) of the lipid phase. Surfactant surface load data indicate that the postsonication might make nonemulsifying Tween 20 diffuse from the aqueous phase to droplet surfaces, which could decrease the crystallinity index (CI) of LNPs due to the inhibition of lipid crystallization. Moreover, the LCO content in lipid matrix could decrease the CI, which could reduce the formation of hydrophobic patches on the particle surface. Therefore, the postsonication and the LCO addition in the matrix could effectively prevent aggregation among hydrophobic patches. This improved colloidal stability of LNPs was verified by the particle shape in transmission electron microscopy and the gelation test. Consequently, LNPs fabricated using 6 min postsonication and 30 wt % LCO in the lipid exhibited the greatest stability (size, 202.3 nm; CI, 57.5%; Tween 20 surface load, 10.29 mg m(-2)). This study may serve as a basis for further research that aims to develop delivery systems for functional foods.

Distribution of a model bioactive within solid lipid nanoparticles and nanostructured lipid carriers influences its loading efficiency and oxidative stability

“…Similar to the melting results, the solidification temperature, solidification peak height and solidification enthalpy also decreased with an increase in the percentage of the liquid lipid content. This is due to the presence of GT in NLCs that reduces the formation of eicosane crystals with the increase in liquid lipid (GT) content (Ban et al, 2014;Teeranachaideekul et al, 2008). These results are similar to the results from some prior studies where similar trends in the melting and solidification curves of NLCs were observed (Anantachaisilp et al, 2010;Ban et al, 2014;Teeranachaideekul et al, 2008).…”

Topical delivery of tetrahydrocurcumin lipid nanoparticles effectively inhibits skin inflammation:in vitroandin vivostudy

“…There was insignificant change (p ≤ 0.05) in particle size, total drug content and entrapment efficiency of THC-SLNs and THC-SLNs gel at 4 ᵒ C ± 3 ᵒ C, 25 ºC ± 2 ºC/60% RH ± 5% RH, 40 ºC ± 2 ºC/75% RH ± 5% RH as given in Tables 3A and B. Though increase in the particle size was observed, however it was below 200 nm, required for enhanced permeation across the stratum corneum 52 . Latter may be assigned to the fact that on cooling SLNs, lipids are not fully crystallized and carbon chains are freezed heterogeneously.…”

Reduction of focal sweating by lipid nanoparticle-delivered myricetin

“…While exothermic peaks of bulk lipid were observed at ~ 44 °C and ~ 35 °C in cooling-calorigrams, the peaks of LNPs appeared at ~ 18 °C, which were attributed to crystal imperfections due to the limited space in nanoscale lipid particles. The lowered crystallization temperature compared with bulk lipid indicates the absence of large particles and destabilized LNPs in the dispersion 28 . These results suggest that M-LNP had very good colloidal stability, thus preventing LNP coalescence, flocculation, and aggregation.…”

“…Myricetin-loaded LNPs were prepared using an oil-in-water emulsion technique with a high-speed blender and sonication probe as reported previously 28 , with slight modifications. First, the lipid (5 wt%) and aqueous (95 wt%) phases were heated to 85 °C and mixed using a high-speed blender (Ultra-Turrax T25D,Ika Werke GmbH & Co., Staufen, Germany) at 8,000 rpm for 1 min and then at 11,000 rpm for 1 min.…”

“…For measuring the PS (z average) and ZP for LNPs passed through the filters, a Zetasizer (Nano ZS90; Malvern Instruments Ltd., Worcestershire, UK) was used and operated at a 90° angle with a helium-neon laser (λ = 633 nm). The ZP measurement was based on the Smoluchowski equation at 25 °C with an electric field strength of 20 V cm −1 . Assuming that all particles are spherical, Γ s was calculated as Ŵ s = C a D/6� , where C a is the concentration of the surfactant adsorbed to the surface of LNPs, D is the PS, and Φ is the lipid phase volume fraction (i.e., 0.05) 28,49 . The method for determining C a values was described previously 50 .…”