Solid Lipid Dispersions: Potential Delivery System for Functional Ingredients in Foods

Chitosan-coated nanostructured lipid carriers for transdermal delivery of tetrahydrocurcumin for breast cancer therapy

Chitosan (Ch)-coated nanostructured lipid carriers (NLCs) have great potential for transdermal delivery with high localization of chemotherapeutics in breast cancer. This study used tetrahydrocurcumin (THC), a primary metabolite of curcumin with enhanced antioxidant and anticancer properties, as a model compound to prepare NLCs. Response surface methodology was employed to optimize THC-loaded Ch-coated NLCs (THC-Ch-NLCs) fabricated by high-shear homogenization. The optimized THC-Ch-NLCs had particle size of 244 ± 18 nm, zeta potential of -17.5 ± 0.5 mV, entrapment efficiency of 76.6 ± 0.2% and drug loading of 0.28 ± 0.01%. In vitro release study of THC-Ch-NLCs showed sustained release following the Korsmeyer-Peppas model with Fickian and non-Fickian diffusion at pH 7.4 and 5.5, respectively. THC-Ch-NLCs demonstrated significantly enhanced in vitro skin permeation, cell uptake, and remarkable cytotoxicity toward MD-MBA-231 breast cancer cells compared to the unencapsulated THC, suggesting Ch-NLCs as potential transdermal nanocarriers of THC for triple-negative breast cancer treatment.

In vitro digestion of edible nanostructured lipid carriers: Impact of a Candelilla wax gelator on performance

In this study, food-grade nanostructured lipid carriers (NLCs) were used as delivery systems to overcome some of the limitations of solid lipid nanoparticles (SLNs) and liquid lipid nanoparticles (LLNs). Organogel NLCs were prepared using an oil phase consisting of a hydrophobic gelator (Candelilla wax) dispersed in liquid corn oil. The oil phase undergoes a gel-to-sol transition when heated, which means that oil-in-water nanoemulsions can be used as templates to form the NLCs. The impact of lipid phase composition on the gastrointestinal fate of the NLCs was determined using a simulated gastrointestinal tract (GIT). The particle size, ζ-potential, and microstructure of the LLNs, NLCs and SLNs were characterized when they were exposed to model oral, gastric, and small intestine conditions. The oil phase in the LLNs and SLNs consisted of pure corn oil and pure Candelilla wax, respectively. Initially, all samples contained small lipid particles (d₄₃ = 150-202 nm) with negative surface potentials (ζ = -26 to -47 mV). The LLNs, SLNs and NLCs behaved similarly in the simulated GIT in terms of their particle properties: there was a large increase in particle size and decrease in charge magnitude in the mouth, stomach, and intestine. The Candelilla wax in the SLNs and NLCs was not digested by lipase, but the corn oil in the LLNs and NLCs was fully digested. This phenomenon may be used to create colloidal delivery systems that can control the release of encapsulated bioactive agents within the GIT.

Physical characterization of high methoxyl pectin and sunflower oil wax emulsions: A low-field 1 H NMR relaxometry study

Pectin-wax-based emulsion systems could be used to form edible films and coatings with desired water permeability characteristics. Pectin is often used in food industry due to its gelling and viscosity increasing properties. Physical properties of pectin are highly dependent on its esterification degree. Waxes are commonly used as edible coatings to enhance the water barrier properties of food products. This study focuses on preparing emulsions with sunflower oil wax (SFW) and high methoxyl pectin (HMP) at different concentrations for any possible edible film or coating formulations. Sunflower oil (SFO) was added as the dispersed oil phase to these emulsions. Characterization of the emulsions was performed by using particle size, rheology, and time domain nuclear magnetic resonance (NMR) relaxometry measurements. Effects of HMP concentration and the presence of SFO in the emulsion formulations were explored. Mean particle size values were recorded between 1 and 3 µm. Rheology measurements showed that increasing HMP concentrations and presence of SFO in emulsions resulted in more pseudoplastic behavior. NMR transverse relaxation times (T₂ ) were measured to detect the differences between the emulsions. Relaxation spectrum analysis was also conducted for a detailed understanding of the transverse relaxations. Addition of SFO and higher HMP concentrations decreased the T ₂ values of the emulsion systems (P < 0.05). However, T₂ decreasing effect of SFO was compensated at 10% (w/w) HMP concentration showing that SFO was well dispersed in this particular emulsion formulation. Changes in the rheological behavior and relaxation times provided insight on the formation and stability of the emulsions. PRACTICAL APPLICATION: Findings of this study can be utilized and integrated to produce edible films and coatings with different water permeability characteristics. This study showed that NMR relaxometry parameters were also effective in monitoring and determining the physical characteristics of the pectin-wax-based emulsion systems as other conventional techniques including rheology and particle size measurements. Our NMR relaxometry findings were in correlation with the flow behavior and particle size results of the investigated emulsion systems.

Scalable Manufacturing Processes for Solid Lipid Nanoparticles

BACKGROUND

Solid lipid nanoparticles offer a range of advantages as delivery systems but they are limited by effective manufacturing processes.

OBJECTIVE

In this study, we outline a high-throughput and scalable manufacturing process for solid lipid nanoparticles.

METHODS

The solid lipid nanoparticles were formulated from a combination of tristearin and 1,2-Distearoyl-phosphatidylethanolamine-methyl-polyethyleneglycol conjugate-2000 and manufactured using the M-110P Microfluidizer processor (Microfluidics Inc, Westwood, Massachusetts, US).

RESULTS

The manufacturing process was optimized in terms of the number of process cycles (1 to 5) and operating pressure (20,000 to 30,000 psi). The solid lipid nanoparticles were purified using tangential flow filtration and they were characterized in terms of their size, PDI, Z-potential and protein loading. At-line particle size monitoring was also incorporated within the process. Our results demonstrate that solid lipid nanoparticles can be effectively manufactured using this process at pressures of 20,000 psi with as little as 2 process passes, with purification and removal of non-entrapped protein achieved after 12 diafiltration cycles. Furthermore, the size could be effectively monitored at-line to allow rapid process control monitoring and product validation.

CONCLUSION

Using this method, protein-loaded solid lipid nanoparticles containing a low (1%) and high (16%) Pegylation were manufactured, purified and monitored for particle size using an at-line system demonstrating a scalable process for the manufacture of these nanoparticles.

Lipid-based nano delivery of antimicrobials to control food-borne bacteria

Direct application of antibacterial agents into foods gives limited advantages because bioactive ingredients may be partially inactivated, neutralized, or easily diffused when contacting with the food matrix. Hence, the aim of this study is to investigate the application of lipid-based nanocarriers as delivery systems for antibacterial ingredients. In this regard, several types of these carriers such as nanoliposomes, nanoemulsions, solid lipid nanoparticles (SLNs), and nanostructured lipid carriers (NLCs) are explored. This study seeks to cover the important challenges of lipid-based nanocarriers including structures and characteristics, properties, production methods, advantages and drawbacks, and their applications to encapsulate antibacterial compounds effectively, particularly in food systems. However, for more scrutiny inspection of the functionality of lipid-based nanocarriers, we have gathered and discussed the studies related to the antibiotic-loaded lipid-based nanoparticles. Also, the role of such nanocarriers in active packaging systems when combining with edible coatings or films is discussed.

Solid lipid nanoparticles as carriers for lipophilic compounds for applications in foods

Nanotechnology is a new subject of interest in the field of food industry. Therefore, scientific and technological studies have been intensified in the last 10 years because of the promising results associated with the potential application of functional properties in food products, such as physical and chemical stability, protection and controlled release of bioactive compounds, and facilitated solubility of lipophilic compounds. Lipids have been used as raw material for the preparation of nanostructures, mainly owing to the solubilization capacity of lipophilic bioactive compounds, as well as because of the advantage of potentially using natural ingredients for production on an industrial scale. Thus, in this review, we describe the information reported in scientific literature on the chemical, physical, and structural properties of lipids used in the preparation of solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). We reviewed the production methods; structural lipid components; emulsifying systems; bioactive lipophilic compounds; and the physical, thermal, and oxidative properties of SLN and NLC. In addition, important methods for characterizing these systems with regard to particle size, polydispersity index, zeta potential, morphology, crystallization behavior, and polymorphism are discussed with examples, in order to support studies that consider physical stability during processing and storage. Furthermore, studies on the applications of SLNs and NLCs in foods are only found for model systems, justifying the compilation of a series of studies on the potential applications to encourage future works. In addition, we have described the aspects still under discussion, related to the possible risks and regulatory aspects of nanotechnology in food.

Inter-Correlation among the Hydrophilic–Lipophilic Balance, Surfactant System, Viscosity, Particle Size, and Stability of Candelilla Wax-Based Dispersions

Owing to a decrease in mineral oil resources, it is crucial to develop packaging materials based on renewable resources. Hence, a water vapor-barrier coating is developed as a natural wax-based dispersion. This dispersion should be stable over the storage time. In this study, the physical stability of a wax-based melt dispersion was analyzed (24 h and 21 days after production), and instability phenomena such as agglomeration, coalescence, and flotation were identified. Furthermore, the inter-correlations among the particle size, viscosity of the continuous phase, physical stability, surfactant chemistry, and hydrophilic–lipophilic balance value were characterized. Particle sizes were described by volume/surface mean d3,2, volume moment mean d4,3, and number mean d1,0 diameter, as well as the span of the volume and number distribution. Stability was characterized by the flotation rate, emulsion stability index, and Turbiscan stability index. Coalescence and agglomeration were not observed after the solidification of the wax particles. A significant correlation was observed for the emulsion stability index, with d3,2, and for flotation rate, with d1,0, d4,3, and viscosity as well, with d1,0, d3,2. Surfactants with hydrophilic–lipophilic balance values of 11–13.5 seem to be the most suitable for stabilizing candelilla wax-in-water suspensions. Particles were smaller, and wax suspensions were better stabilized using Tween 20 and Span 20, compared with Tween 80 and Span 80.