Stability and characterization of O/W free phytosterols nanoemulsions formulated with an enzymatically modified emulsifier

Nanoemulsions of betulinic acid stabilized with modified phosphatidylcholine increase the stability of the nanosystems and the drug's bioavailability

Betulinic acid (BA) is a natural compound with significant potential for treating various diseases, including cancer and AIDS, and possesses additional anti-inflammatory and antibacterial properties. However, its clinical application is limited because of its low solubility in water, which impairs its distribution within the body. To overcome this challenge, nanoemulsions have been developed to improve the bioavailability of such poorly soluble drugs. This study investigated modified phosphatidylcholine (PC), where some fatty acids were replaced with conjugated linoleic acid (CLA) to stabilize BA nanoemulsions. The modified PC was used to prepare nanoemulsions with droplet sizes of up to 45 nanometers. These nanoemulsions maintained stability for 60 days at room temperature (25°C±2°C) and under refrigeration (5°C±1°C), with no signs of instability. Nanoemulsions stabilized with CLA-modified PC achieved a higher drug encapsulation rate (93.5±4.3 %) than those using natural PC (82.8±4.2 %). In an in vivo model, both nanoemulsion formulations significantly increased BA absorption, with CLA-modified PC enhancing absorption by 21.3±1.3 times and natural PC by 20±2.3 times compared to the free drug. This suggests that nanoemulsions with modified PC could improve the stability and efficacy of BA in clinical applications.

Chitosan-coated soybean protein isolate/lecithin nanoparticles for enhancing the stability and bioaccessibility of phytosterol

BACKGROUND

Phytosterols (PS) have various beneficial effects on human health, especially the property of reducing blood cholesterol. However, the low solubility and bioaccessibility of PS have greatly limited their application in functional food ingredients.

RESULTS

To improve the bioaccessibility and stability of PS, chitosan-coated PS nanoparticles (CS-PNP) were successfully prepared by self-assembly. The properties of CS-PNP, including size, zeta potential, encapsulation efficiency (EE) and loading amount (LA) were characterised. The optimisation of CS concentration (0.4 mg mL-1) and pH (3.5) resulted in the formation of CS-PNP with an EE of over 90% and a particle size of 187.7 nm. Due to the special properties of CS chitosan, the interaction between CS and soybean protein isolate (SPI)/lecithin (SL) led to the formation of a soluble complex. CS-PNP exhibited good stability to temperature variations but was more sensitive to salt ions. During in vitro digestion, CS efficiently maintained the stability of nanoparticles against the hydrolysis of SPI by pepsin under acidic conditions. However, these nanoparticles tended to aggregate in a neutral intestinal environment. After 3 h of in vitro digestion, the bioaccessibility of PS increased from 18.2% of free PS to 63.5% of CS-PNP.

CONCLUSION

Overall, these results highlight the potential of chitosan-coated nanoparticles as effective carriers for the oral administration of PS. This multilayer construction may serve as a promising for applications in food products as delivery vehicles for nutraceuticals. © 2024 Society of Chemical Industry.

Process Optimization of Tinospora cordifolia Extract-Loaded Water in Oil Nanoemulsion Developed by Ultrasound-Assisted Homogenization

Nanoemulsions are gaining interest in a variety of products as a means of integrating easily degradable bioactive compounds, preserving them from oxidation, and increasing their bioavailability. However, preparing stable emulsion compositions with the desired characteristics is a difficult task. The aim of this study was to encapsulate the Tinospora cordifolia aqueous extract (TCAE) into a water in oil (W/O) nanoemulsion and identify its critical process and formulation variables, like oil (27-29.4 mL), the surfactant concentration (0.6-3 mL), and sonication amplitude (40% to 100%), using response surface methodology (RSM). The responses of this formulation were studied with an analysis of the particle size (PS), free fatty acids (FFAs), and encapsulation efficiency (EE). In between, we have studied a fishbone diagram that was used to measure risk and preliminary research. The optimized condition for the formation of a stable nanoemulsion using quality by design was surfactant (2.43 mL), oil concentration (27.61 mL), and sonication amplitude (88.6%), providing a PS of 171.62 nm, FFA content of 0.86 meq/kg oil and viscosity of 0.597 Pa.s for the blank sample compared to the enriched TCAE nanoemulsion with a PS of 243.60 nm, FFA content of 0.27 meq/kg oil and viscosity of 0.22 Pa.s. The EE increases with increasing concentrations of TCAE, from 56.88% to 85.45%. The RSM response demonstrated that both composition variables had a considerable impact on the properties of the W/O nanoemulsion. Furthermore, after the storage time, the enriched TCAE nanoemulsion showed better stability over the blank nanoemulsion, specially the FFAs, and the blank increased from 0.142 to 1.22 meq/kg oil, while TCAE showed 0.266 to 0.82 meq/kg.

Current and New Insights on Delivery Systems for Plant Sterols in Food

Plant sterols are minor bioactive components of food lipids, which are often used for the formulation of functional foods due to their cholesterol-lowering properties. However, they have low solubility and tend to crystallize, which may affect their biological effects, the sensory profile of the sterol-enriched food, and its consumer acceptability. Moreover, due to the unsaturated structure of sterols, they are susceptible to oxidation, so different encapsulation systems have been developed to improve their dispersibility/solubility, stability, delivery, and bioaccessibility. This chapter provides an overview of the main encapsulation systems currently used for plant sterols and their application in model and food systems, with a particular focus on their efficiency and impact on sterol bioaccessibility.

Lipid Nanoparticles: An Effective Tool to Improve the Bioavailability of Nutraceuticals

Nano-range bioactive colloidal carrier systems are envisaged to overcome the challenges associated with treatments of numerous diseases. Lipid nanoparticles (LNPs), one of the extensively investigated drug delivery systems, not only improve pharmacokinetic parameters, transportation, and chemical stability of encapsulated compounds but also provide efficient targeting and reduce the risk of toxicity. Over the last decades, nature-derived polyphenols, vitamins, antioxidants, dietary supplements, and herbs have received more attention due to their remarkable biological and pharmacological health and medical benefits. However, their poor aqueous solubility, compromised stability, insufficient absorption, and accelerated elimination impede research in the nutraceutical sector. Owing to the possibilities offered by various LNPs, their ability to accommodate both hydrophilic and hydrophobic molecules and the availability of various preparation methods suitable for sensitive molecules, loading natural fragile molecules into LNPs offers a promising solution. The primary objective of this work is to explore the synergy between nature and nanotechnology, encompassing a wide range of research aimed at encapsulating natural therapeutic molecules within LNPs.

Design and simulation of a caprylic acid enzymatically modified phosphatidylcholine micelle using a coarse-grained molecular dynamics simulations approach

Computationally simulated micelle models provide useful structural information on the molecular and biological sciences. One strategy to study the self-aggregation process of surfactant molecules that make up a micelle is through molecular dynamics (MD) simulations. In this study, a theoretical approach with a coarse-grained MD simulation (CG-MD) was employed to evaluate the critical micellar concentration (CMC), the micellization process, building a tridimensional (3D) model system of a micelle using data from the experimentally enzymatically modified phospholipids (PL) by phospholipase A1 (PA1). This required enzymatic interesterification of soybean phosphatidylcholine (PC) with caprylic acid, along with purification and characterization by chromatographic techniques to measure the esterified fatty acids and the corresponding PL composition. The number of molecules used in the CG-MD simulation system was determined from the experimental CMC data which was 0.025%. The molecular composition of the system is: 1 C 18:2, 2 C 8:0/8:0, 3 C 8:0/18:3n-9, 4 C 8:0/18:0, 5 C8:0/18:2n-6, 6 C8:0/18:1n-9, and 7 C 8:0/16:0. According to our theoretical results, the micelle model is structurally stable with an average Rg of 3.64 ± 0.10 Å, and might have an elliptical form with a radius of 24.6 Å. Regarding CMC value there was a relationship between the experimental data of the modified PLs and the theoretical analysis by GC-MD, which suggest that the enzymatic modification of PLs does not affect their self-aggregation properties. Finally, the micellar system obtained in the current research can be used as a simple and useful model to design optimal biocompatible nanoemulsions as possible vehicles for bioactive small molecules.Communicated by Ramaswamy H. Sarma.

Production, Characterization, Delivery, and Cholesterol-Lowering Mechanism of Phytosterols: A Review

Phytosterols are natural plant-based bioactive compounds that can lower blood cholesterol levels and help prevent cardiovascular diseases. Consequently, they are being utilized in functional foods, supplements, and pharmaceutical products designed to improve human health. This paper summarizes different approaches to isolate, purify, and characterize phytosterols. It also discusses the hypolipidemic mechanisms of phytosterols and their impact on cholesterol transportation. Phytosterols have a low water-solubility, poor chemical stability, and limited bioavailability, which limits their utilization and efficacy in functional foods. Strategies are therefore being developed to overcome these shortcomings. Colloidal delivery systems, such as emulsions, oleogels, liposomes, and nanoparticles, have been shown to be effective at improving the water-dispersibility, stability, and bioavailability of phytosterols. These delivery systems can be used to incorporate phytosterols into a broader range of cholesterol-lowering functional foods and beverages. We also discuses several issues that need to be addressed before these phytosterol delivery systems can find widespread commercial utilization.

Development of Phosphatidylcholine/Tween 80 based biocompatible clove oil-in-water nanoemulsion as a green nanocarrier for controlled herbicide delivery

Recently, the development of ecofriendly and biocompatible agrochemical delivery systems has garnered widespread attention because of their great potential in sustainable agri-food applications. Atrazine (ATZ) is a globally used herbicide used to control weeds, but it suffers from poor aqueous solubility, poor efficacy, and environmental loss. Herein, we report a novel, eco-friendly and biocompatible clove oil-based nanoemulsion as a green nanocarrier to enhance the solubility, bioavailability, and control release of ATZ. Food grade surfactants, Tween 80 and Phosphatidylcholine (PC) were used to formulate clove oil nanoemulsion with size <200 nm using ultrasonic emulsification technique, without any use of organic solvent. The ATZ encapsulation efficiency in NEm was greater than 95%. DLS confirms the nanosize (106 nm) and monodispersity of NEm. HRTEM reveals the spherical morphology of the nanodroplets. FTIR and DSC confirm the successful incorporation of ATZ inside the NEm oil droplet core. ATZ loaded NEm showed excellent thermal and storage stability, low Ostwald ripening rate, slow and sustained herbicide release behavior, which is of vital importance for an herbicide formulation. The release rate was better than commercial ATZ and free ATZ formulations. Results from herbicidal activity assays demonstrate that ATZ NEm exhibited excellent herbicidal activity even at low concentrations as compared to commercial ATZ analogs. In consideration of biocompatible excipients, free of organic solvent, and a simple fabrication process, ATZ loaded clove oil NEm can hold great potential in weed control and sustainable agri-food applications.

Water-Dispersible Phytosterol Nanoparticles: Preparation, Characterization, and in vitro Digestion

For improving solubility and bioaccessibility of phytosterols (PS), phytosterol nanoparticles (PNPs) were prepared by emulsification–evaporation combined high-pressure homogenization method. The organic phase was formed with the dissolved PS and soybean lecithin (SL) in anhydrous ethanol, then mixed with soy protein isolate (SPI) solution, and homogenized into nanoparticles, followed by the evaporation of ethanol. The optimum fabrication conditions were determined as PS (1%, w/v): SL of 1:4, SPI content of 0.75% (w/v), and ethanol volume of 16 ml. PNPs were characterized to have average particle size 93.35 nm, polydispersity index (PDI) 0.179, zeta potential −29.3 mV, and encapsulation efficiency (EE) 97.3%. The impact of temperature, pH, and ionic strength on the stability of fabricated PNPs was determined. After 3-h in vitro digestion, the bioaccessibility of PS in nanoparticles reached 70.8%, significantly higher than the 18.2% of raw PS. Upon freeze-drying, the particle size of PNPs increased to 199.1 nm, resulting in a bimodal distribution. The solubility of PS in water could reach up to 2.122 mg/ml, ~155 times higher than that of raw PS. Therefore, this study contributes to the development of functional PS-food ingredients.

Innovative Delivery Systems Loaded with Plant Bioactive Ingredients: Formulation Approaches and Applications

Plants constitute a rich source of diverse classes of valuable phytochemicals (e.g., phenolic acids, flavonoids, carotenoids, alkaloids) with proven biological activity (e.g., antioxidant, anti-inflammatory, antimicrobial, etc.). However, factors such as low stability, poor solubility and bioavailability limit their food, cosmetics and pharmaceutical applications. In this regard, a wide range of delivery systems have been developed to increase the stability of plant-derived bioactive compounds upon processing, storage or under gastrointestinal digestion conditions, to enhance their solubility, to mask undesirable flavors as well as to efficiently deliver them to the target tissues where they can exert their biological activity and promote human health. In the present review, the latest advances regarding the design of innovative delivery systems for pure plant bioactive compounds, extracts or essential oils, in order to overcome the above-mentioned challenges, are presented. Moreover, a broad spectrum of applications along with future trends are critically discussed.

Preparation and characterization of phytosterol-loaded nanoparticles with sodium caseinate/dextran conjugates

Sodium caseinate (SC)/dextran conjugates were prepared via Maillard reaction under controlled dry-heating conditions. Moreover, the nanoparticles of phytosterols (PS) encapsulated by SC or SC/dextran were produced using the emulsion evaporation method. The encapsulation efficiency (78.81 ± 5.22%) of PS in SC/dextran nanoparticles was higher than that (73.5 ± 2.78%) in SC nanoparticles. Compared with the compact and dense structure of SC nanoparticles, SC/dextran nanoparticles existed as relatively loose aggregates. The result of differential scanning calorimetry demonstrated that the encapsulation of PS greatly decreased its crystallinity. The released rates of PS from SC and SC/dextran nanoparticles under acidic gastric conditions were 8.59% and 4.73%, respectively. After 7 h of intestinal digestion, the released rate (52.19%) of PS from SC/dextran nanoparticles was significantly higher than that from SC (32.67%) nanoparticles. Therefore, SC/dextran conjugates prepared by the Maillard reaction are more suitable to be used as wall material for the nano-encapsulation of PS.

A review on chemical and physical modifications of phytosterols and their influence on bioavailability and safety

Phytosterols have been shown to lower cholesterol levels and to have antioxidant, anti-inflammatory and other biological activities. However, the high melting point and poor solubility limit their bioavailability and practical application. It is advantageous to modify phytosterols chemically and physically. This article reviews and discusses the chemical and physical modifications of phytosterols, as well as their effects on the bioavailability and possible toxicity in vivo. The current research on chemical modifications is mainly focused on esterification to increase the oil solubility and water solubility. For physical modifications (mainly microencapsulation), there are biopolymer-based, surfactant-based and lipid-based nanocarriers. Both chemical and physical modifications of phytosterols can effectively increase the absorption and bioavailability. The safety of modified phytosterols is also an important issue. Phytosterol esters are generally considered to be safe. However, phytosterol oxides, which may be produced during the synthesis of phytosterol esters, have shown toxicity in animal models. The toxicity of nanocarriers also needs further studies.

Analytical Strategies to Analyze the Oxidation Products of Phytosterols, and Formulation-Based Approaches to Reduce Their Generation

Phytosterols are a class of lipid molecules present in plants that are structurally similar to cholesterol and have been widely utilized as cholesterol-lowering agents. However, the susceptibility of phytosterols to oxidation has led to concerns regarding their safety and tolerability. Phytosterol oxidation products (POPs) present in a variety of enriched and non-enriched foods can show pro-atherogenic and pro-inflammatory properties. Therefore, it is crucial to screen and analyze various phytosterol-containing products for the presence of POPs and ultimately design or modify phytosterols in such a way that prevents the generation of POPs and yet maintains their pharmacological activity. The main approaches for the analysis of POPs include the use of mass spectrometry (MS) linked to a suitable separation technique, notably gas chromatography (GC). However, liquid chromatography (LC)-MS has the potential to simplify the analysis due to the elimination of any derivatization step, usually required for GC-MS. To reduce the transformation of phytosterols to their oxidized counterparts, formulation strategies can theoretically be adopted, including the use of microemulsions, microcapsules, micelles, nanoparticles, and liposomes. In addition, co-formulation with antioxidants, such as tocopherols, may prove useful in substantially preventing POP generation. The main objectives of this review article are to evaluate the various analytical strategies that have been adopted for analyzing them. In addition, formulation approaches that can prevent the generation of these oxidation products are proposed.

Effect of environmental stresses on physicochemical properties of ALA oil-in-water nanoemulsion system prepared by emulsion phase inversion

To solve the stability and oxidation issues of alpha-linolenic acid (ALA), this study focused on developing ALA nanoemulsion system (ALA-NE, oil-in-water) and evaluating the effect of environmental conditions on physical stability and the effect of antioxidants on oxidative stability. The physicochemical properties of nanoemulsions were measured at different conditions, including particle diameter, zeta potential, retention rate and peroxidation value (POV). The particle diameter increased significantly and the retention rate decreased after 25 days storage under the conditions of high temperature and metal ions. However, the influence of ionic strength, pH and light was insignificant. As an antioxidant, Vitamin E was more effective at retarding lipid oxidation of nanoemulsions than that of vitamin C. These results provided reference information in preparing effective and stable ALA-NE systems and enlarging the application fields.

Morphology and microstructural analysis of bioactive-loaded micro/nanocarriers via microscopy techniques; CLSM/SEM/TEM/AFM

Efficient characterization of the physicochemical attributes of bioactive-loaded micro/nano-vehicles is crucial for the successful product development. The introduction of outstanding science-based strategies and techniques makes it possible to realize how the characteristics of the formulation ingredients affect the structural and (bio)functional properties of the final bioactive-loaded carriers. The important points to be solved, at a microscopic level, are investigating how the features of the formulation ingredients affect the morphology, surface, size, dispersity, as well as the particulate interactions within bioactive-comprising nano/micro-delivery systems. This review presents a detailed description concerning the application of advanced microscopy techniques, i.e., confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) in characterizing the attributes of nano/microcarriers for the efficient delivery of bioactive compounds. Furthermore, the fundamental principles of these approaches, instrumentation, specific applications, and the strategy to choose the most proper technique for different carriers has been discussed.

Food-Grade Nanoemulsions: Preparation, Stability and Application in Encapsulation of Bioactive Compounds

Nanoemulsions have attracted significant attention in food fields and can increase the functionality of the bioactive compounds contained within them. In this paper, the preparation methods, including low-energy and high-energy methods, were first reviewed. Second, the physical and chemical destabilization mechanisms of nanoemulsions, such as gravitational separation (creaming or sedimentation), flocculation, coalescence, Ostwald ripening, lipid oxidation and so on, were reviewed. Then, the impact of different stabilizers, including emulsifiers, weighting agents, texture modifiers (thickening agents and gelling agents), ripening inhibitors, antioxidants and chelating agents, on the physicochemical stability of nanoemulsions were discussed. Finally, the applications of nanoemulsions for the delivery of functional ingredients, including bioactive lipids, essential oil, flavor compounds, vitamins, phenolic compounds and carotenoids, were summarized. This review can provide some reference for the selection of preparation methods and stabilizers that will improve performance in nanoemulsion-based products and expand their usage.

Nanoemulsions: Factory for Food, Pharmaceutical and Cosmetics

Nanotechnology, particularly nanoemulsions (NEs), have gained increasing interest from researchers throughout the years. The small-sized droplet with a high surface area makes NEs important in many industries. In this review article, the components, properties, formation, and applications are summarized. The advantages and disadvantages are also described in this article. The formation of the nanosized emulsion can be divided into two types: high and low energy methods. In high energy methods, high-pressure homogenization, microfluidization, and ultrasonic emulsification are described thoroughly. Spontaneous emulsification, phase inversion temperature (PIT), phase inversion composition (PIC), and the less known D-phase emulsification (DPE) methods are emphasized in low energy methods. The applications of NEs are described in three main areas which are food, cosmetics, and drug delivery.