Study on the preparation of stabilizer-free silymarin nanocrystals and its oral absorption mechanisms

Many researchers have studied the oral absorption mechanisms yet, however, considering stabilizers often participate in the absorption process of nanocrystals, these known mechanisms may be incorrect. Hence in this study, we aimed to explore the correct absorption mechanism of nanocrystals by performing related studies on stabilizer-free nanocrystals. We firstly prepared stabilizer-free silymarin nanocrystals by high-pressure homogenization, and then performed absorption-related studies, such as solubility, dissolution rate, pharmacokinetic study, cellular uptake and intracellular transport. Results showed the stabilizer-free silymarin nanocrystals had an average particle size of (450.2 ± 4.46) nm, with PDI of 0.280 ± 0.021 and Zeta potential of -26.9 ± 2.4 mV. The conversion of silymarin crude drug to stabilizer-free silymarin nanocrystals increased the compound's solubility by 1.41 times, with a dissolution rate of 92.2 % in water within 30 min compared to 38.5 % for crude drugs. Pharmacokinetic studies showed the oral bioavailability of stabilizer-free silymarin nanocrystals was found to be 1.48 times greater than that of the crude drugs. The cell experimentation results demonstrated that the stabilizer-silymarin nanocrystals can improve uptake but have poor transmembrane transport properties. Most researchers believe that nanocrystals can enhance transmembrane transport of drugs via an endocytosis-mediated pathway. In fact, nanocrystals are indeed endocytosed more by the cells, but this transport pathway is poor because the cells lack the intracellular transport pathway to transport nanocrystals from the AP side to the BP side. Therefore, we believe that the intracellular transport of nanocrystals can be enhanced by modifications and other carriers if needed to improve nanocrystals' ability to promote oral absorption.

Lipid-based nanocarriers for enhanced delivery of plant-derived bioactive molecules: a comprehensive review

Bioactive compounds derived from plants have been investigated for treating various pathological conditions. However, the utilization of these compounds has challenges such as instability, low solubility and bioavailability. To overcome these challenges, the encapsulation of bioactive molecules with in a novel nano carrier system enabling effective delivery and clinical translation has become essential. Lipid-based nanocarriers provide versatile platforms for encapsulating and delivering bioactive compounds and overcome the challenges. These novel carriers can improve solubility, stability, improved drug retention and therapeutic efficacy of plant derived bioactive compounds. The current review evaluates the challenges in delivery of plant bioactives and highlights the potential of various lipid-based nano carriers designed to improve its therapeutic efficacy.

The Use of Nanocarriers to Enhance the Anti-neuroinflammatory Potential of Dietary Flavonoids in Animal Models of Neurodegenerative Diseases: A Systematic Review

BACKGROUND

Neurodegenerative diseases (NDs) have become a common and growing cause of mortality and morbidity worldwide, especially in older adults. The natural flavonoids found in fruits and vegetables have been shown to have therapeutic effects against many diseases, including NDs; however, in general, flavonoids have limited bioavailability to the target cells. One promising strategy to increase bioavailability is to entrap them in nanocarriers.

OBJECTIVE

This article aims to review the potential role of nanocarriers in enhancing the antineuroinflammatory efficacy of flavonoids in experimentally induced ND.

METHODS

A literature search was conducted in the scientific databases using the keywords "neurodegenerative", "anti-neuroinflammatory", "dietary flavonoids," "nanoparticles", and "therapeutic mechanisms".

RESULTS

A total of 289 articles were initially identified, of which 45 articles reported on flavonoids. After completion of the selection process, five articles that met the criteria of the review were selected for analysis. Preclinical studies identified in this review showed that nanoencapsulated flavonoids attenuated cognitive impairment and seizure, improved behavioral patterns, and reduced levels of astrocytes. Importantly, they exhibited strong antioxidant properties, increasing the levels of antioxidant enzymes and reducing oxidative stress (OS) biomarkers. Moreover, nanocarrier-complexed flavonoids decreased the levels of the pro-inflammatory cytokines, interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α), by inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and nod-like receptor protein 3 inflammasome activation (NLRP3). They also had remarkable effects on important ND-related neurotransmitters, improved cognitive function via cholinergic neurotransmission, and increased prefrontal cortical and hippocampal norepinephrine (NE) and 5-hydroxytryptamine (5-HT).

CONCLUSION

Nanoencapsulated flavonoids should, therefore, be considered a novel therapeutic approach for the treatment of NDs.

Impact of nanotechnology on the oral delivery of phyto-bioactive compounds

Nanotechnology is an advanced field that has remarkable nutraceutical and food applications. Phyto-bioactive compounds (PBCs) play critical roles in promoting health and disease treatment. However, PBCs generally encounter several limitations that delay their widespread application. For example, most PBCs have low aqueous solubility, poor biostability, poor bioavailability, and a lack of target specificity. Moreover, the high concentrations of effective PBC doses also limit their application. As a result, encapsulating PBCs into an appropriate nanocarrier may increase their solubility and biostability and protect them from premature degradation. Moreover, nanoencapsulation could improve absorption and prolong circulation with a high opportunity for targeted delivery that may decrease unwanted toxicity. This review addresses the main parameters, variables, and barriers that control and affect oral PBC delivery. Moreover, this review discusses the potential role of biocompatible and biodegradable nanocarriers in improving the water solubility, chemical stability, bioavailability, and specificity/selectivity of PBCs.

Nanodelivery of Dietary Polyphenols for Therapeutic Applications

Advancement in nanotechnology has unleashed the therapeutic potentials of dietary polyphenols by enhancing bioavailability, improving biological half-life, and allowing site-specific drug delivery. In this review, through citation of relevant literature reports, we discuss the application of nano-pharmaceutical formulations, such as solid lipid nanoparticles, nano-emulsions, nano-crystals, nano-polymersomes, liposomes, ethosomes, phytosomes, and invasomes for dietary polyphenols. Following this, we highlight important studies concerning different combinations of nano formulations with dietary polyphenols (also known as nanophytopolyphenols). We also provide nano-formulation paradigms for enhancing the physicochemical properties of dietary polyphenols. Finally, we highlight the latest patents that were granted on nano-formulations of dietary polyphenols. Based on our review, we observe that nanosized delivery of herbal constituents, spices, and dietary supplements have the ability to improve biological processes and address issues connected with herbal treatments.

Development of New Natural Lipid-Based Nanoparticles Loaded with Aluminum-Phthalocyanine for Photodynamic Therapy against Melanoma

Photodynamic therapy (PDT) mediated by photosensitizers loaded in nanostructures as solid lipid nanoparticles has been pinpointed as an effective and safe treatment against different skin cancers. Amazon butters have an interesting lipid composition when it comes to forming solid lipid nanoparticles (SLN). In the present report, a new third-generation photosensitizing system consisting of aluminum-phthalocyanine associated with Amazon butter-based solid lipid nanoparticles (SLN-AlPc) is described. The SLN was developed using murumuru butter, and a monodisperse population of nanodroplets with a hydrodynamic diameter of approximately 40 nm was obtained. The study of the permeation of these AlPc did not permeate the analyzed skin, but when incorporated into the system, SLN-AlPc allowed permeation of almost 100% with 8 h of contact. It must be emphasized that SLN-AlPc was efficient for carrying aluminum-phthalocyanine photosensitizers and exhibited no toxicity in the dark. Photoactivated SLN-AlPc exhibited a 50% cytotoxicity concentration (IC₅₀) of 19.62 nM when applied to B16-F10 monolayers, and the type of death caused by the treatment was apoptosis. The exposed phospholipid phosphatidylserine was identified, and the treatment triggered a high expression of Caspase 3. A stable Amazon butter-based SLN-AlPc formulation was developed, which exhibits strong in vitro photodynamic activity on melanoma cells.

Nano-enabled plant-based colloidal delivery systems for bioactive agents in foods: Design, formulation, and application

Consumers are becoming increasingly aware of the impact of their dietary choices on the environment, animal welfare, and health, which is causing many of them to adopt more plant-based diets. For this reason, many sectors of the food industry are reformulating their products to contain more plant-based ingredients. This article describes recent research on the formation and application of nano-enabled colloidal delivery systems formulated from plant-based ingredients, such as polysaccharides, proteins, lipids, and phospholipids. These delivery systems include nanoemulsions, solid lipid nanoparticles, nanoliposomes, nanophytosomes, and biopolymer nanoparticles. The composition, size, structure, and charge of the particles in these delivery systems can be manipulated to create novel or improved functionalities, such as improved robustness, higher optical clarity, controlled release, and increased bioavailability. There have been major advances in the design, assembly, and application of plant-based edible nanoparticles within the food industry over the past decade or so. As a result, there are now a wide range of different options available for creating delivery systems for specific applications. In the future, it will be important to establish whether these formulations can be produced using economically viable methods and provide the desired functionality in real-life applications.

Bioactive Loaded Novel Nano-Formulations for Targeted Drug Delivery and Their Therapeutic Potential

Plant-based medicines have received a lot of attention in recent years. Such medicines have been employed to treat medical conditions since ancient times, and in those times only the observed symptoms were used to determine dose accuracy, dose efficacy, and therapy. Rather than novel formulations, the current research work on plant-based medicines has mostly concentrated on medicinal active phytoconstituents. In the past recent decades, however, researchers have made significant progress in developing "new drug delivery systems" (NDDS) to enhance therapeutic efficacy and reduce unwanted effects of bioactive compounds. Nanocapsules, polymer micelles, liposomes, nanogels, phytosomes, nano-emulsions, transferosomes, microspheres, ethosomes, injectable hydrogels, polymeric nanoparticles, dendrimers, and other innovative therapeutic formulations have all been created using bioactive compounds and plant extracts. The novel formulations can improve solubility, therapeutic efficacy, bioavailability, stability, tissue distribution, protection from physical and chemical damage, and prolonged and targeted administration, to name a few. The current study summarizes existing research and the development of new formulations, with a focus on herbal bioactive components.

Nanotechnology-based medicinal products and patents: a promising way to treat psoriasis

Psoriasis is an autoimmune skin disorder that is characterised by chronic inflammation and erythematous scaly patches. It has a significant impact on the patient's quality of life and can cause psychological stress. There are several aspects which cause psoriasis for instance, environmental issues, immune disorders, bacterial infections, and genetic issues. Plentiful therapeutic means or treatments are accessible, but not any of them can completely and effectively cure psoriasis without hindering patient compliance. Hence, it becomes challenging to discover a new drug moiety or any drug delivery method to cure psoriasis. Conventional treatment of psoriasis involves anti-inflammatory agents, immune suppressants, phototherapy, and biologic treatment, those were given in different forms such as topical, oral, or systemic formulations, but these all were unsuccessful to accomplish complete reduction of psoriasis as well as causing adverse side effects. In terms of dose frequency, doses, efficacy, and side effects, nanotechnology-based new formulations are the most promising prospects for addressing the challenges and limits associated with present psoriasis formulations. Hence, our major goal of this review is to present various advanced nanotechnological approaches for effective topical treatment of psoriasis. In short, nano-formulations continue to be formed as very promising modality in the treatment of psoriasis as they suggest improved penetration, targeted delivery, increased safety, and efficacy.

Modern Nanocarriers as a Factor in Increasing the Bioavailability and Pharmacological Activity of Flavonoids

This review is devoted to modern systems of nanocarriers that ensure the targeted delivery of flavonoids to various organs and systems. Flavonoids have wide range of effects on the human body due to their antioxidant, anti-inflammatory, antitumor, antimicrobial, antiplatelet and other types of activity. However, the low bioavailability of flavonoids significantly limits their practical application. To overcome this disadvantage, serious efforts have been made in recent years to develop nanoscale carriers for flavonoids. This is particularly important in view of the known antitumor effect of these compounds, which allows them to target tumor cells without affecting surrounding healthy tissues. Nanocarriers provide increased penetration of biologicals into specific organs in combination with controlled and prolonged release, which markedly improves their effectiveness. This review summarizes data on the use of phytosomes, lipid-based nanoparticles, as well as polymeric and inorganic nanoparticles; their advantages and drawbacks are analyzed; the prospect of their use is discussed that opens new possibilities for the clinical application of flavonoids.

Design of Hepatic Targeted Drug Delivery Systems for Natural Products: Insights into Nomenclature Revision of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), recently renamed metabolic-dysfunction-associated fatty liver disease (MAFLD), affects a quarter of the worldwide population. Natural products have been extensively utilized in treating NAFLD because of their distinctive advantages over chemotherapeutic drugs, despite the fact that there are no approved drugs for therapy. Notably, the limitations of many natural products, such as poor water solubility, low bioavailability in vivo, low hepatic distribution, and lack of targeted effects, have severely restricted their clinical application. These issues could be resolved via hepatic targeted drug delivery systems (HTDDS) that boost clinical efficacy in treating NAFLD and decrease the adverse effects on other organs. Herein an overview of natural products comprising formulas, single medicinal plants, and their crude extracts has been presented to treat NAFLD. Also, the clinical efficacy and molecular mechanism of active monomer compounds against NAFLD are systematically discussed. The targeted delivery of natural products via HTDDS has been explored to provide a different nanotechnology-based NAFLD treatment strategy and to make suggestions for natural-product-based targeted nanocarrier design. Finally, the challenges and opportunities put forth by the nomenclature update of NAFLD are outlined along with insights into how to improve the NAFLD therapy and how to design more rigorous nanocarriers for the HTDDS. In brief, we summarize the up-to-date developments of the NAFLD-HTDDS based on natural products and provide viewpoints for the establishment of more stringent anti-NAFLD natural-product-targeted nanoformulations.

Systematic review of pharmacokinetics and potential pharmacokinetic interactions of flavonolignans from silymarin

Silymarin is an extract from the seeds (fruits) of Silybum marianum that contains flavonolignans and flavonoids. Although it is frequently used as a hepatoprotective agent, its application remains somewhat debatable, in particular, due to the low oral bioavailability of flavonolignans. Moreover, there are claims of its potential interactions with concomitantly used drugs. This review aims at a systematic summary and critical assessment of known information on the pharmacokinetics of particular silymarin flavonolignans. There are two known major reasons for poor systemic oral bioavailability of flavonolignans: (1) rapid conjugation in intestinal cells or the liver and (2) efflux of parent flavonolignans or formed conjugates back to the lumen of the gastrointestinal tract by intestinal cells and rapid excretion by the liver into the bile. The metabolism of phase I appears to play a minor role, in contrast to extensive conjugation and indeed the unconjugated flavonolignans reach low plasma levels after common doses. Only about 1%-5% of the administered dose is eliminated by the kidneys. Many in vitro studies tested the inhibitory potential of silymarin and its components toward different enzymes and transporters involved in the absorption, metabolism, and excretion of xenobiotics. In most cases, effective concentrations are too high to be relevant under real biological conditions. Most human studies showed no silymarin-drug interactions explainable by these suggested interferences. More interactions were found in animal studies, likely due to the much higher doses administered.

Structured edible lipid-based particle systems for oral drug-delivery

Oral administration is the most popular and patient-compliant route for drug delivery, though it raises great challenges due to the involvement of the gastro-intestine (GI) system and the drug bioavailability. Drug bioavailability is directly related to its ability to dissolve, transport and/or absorb through the physiological environment. A great number of drugs are characterized with low water solubility due to their hydrophobic nature, thus limiting their oral bioavailability and clinical use. Therefore, new strategies aiming to provide a protective shell through the GI system and improve drug solubility and permeability in the intestine were developed to overcome this limitation. Lipid-based systems have been proposed as good candidates for such a task owing to their hydrophobic nature which allows high drug loading, drug micellization ability during intestinal digestion due to the lipid content, and the vehicle physical protective environment. The use of edible lipids with high biocompatibility paves the bench-to-bedside translation. Four main types of structured lipid-based drug delivery systems differing in the physical state of the lipid phase have been described in the literature, namely emulsions, solid lipid nanoparticles, nanostructured lipid carriers, and oleogel-based particles. The current review provides a comprehensive overview of the different structured edible lipid-based oral delivery systems investigated up to date and emphasizes the contribution of each system component to the delivery performance, and the oral delivery path of lipids.

Lipid Nanoparticles as Carriers for Bioactive Delivery

Nanotechnology has made a great impact on the pharmaceutical, biotechnology, food, and cosmetics industries. More than 40% of the approved drugs are lipophilic and have poor solubility. This is the major rate-limiting step that influences the release profile and bioavailability of drugs. Several approaches have been reported to administer lipophilic drugs with improved solubility and bioavailability. Nanotechnology plays a crucial role in the targeted delivery of poorly soluble drugs. Nanotechnology-based drug delivery systems can be classified as solid lipid nanoparticulate drug delivery systems, emulsion-based nanodrug delivery systems, vesicular drug delivery systems, etc. Nanotechnology presents a new frontier in research and development to conquer the limitations coupled with the conventional drug delivery systems through the formation of specific functionalized particles. This review presents a bird's eye view on various aspects of lipid nanoparticles as carriers of bioactive molecules that is, synthesis, characterization, advantage, disadvantage, toxicity, and application in the medical field. Update on recent development in terms of patents and clinical trials of solid lipid nanoparticles (SLNs) and nanostructure lipid carriers (NLCs) have also been discussed in this article.

Recent advances in drug delivery applications of cubosomes, hexosomes, and solid lipid nanoparticles

The use of lipid nanocarriers for drug delivery applications is an active research area, and a great interest has particularly been shown in the past two decades. Among different lipid nanocarriers, ISAsomes (Internally self-assembled somes or particles), including cubosomes and hexosomes, and solid lipid nanoparticles (SLNs) have unique structural features, making them attractive as nanocarriers for drug delivery. In this contribution, we focus exclusively on recent advances in formation and characterization of ISAsomes, mainly cubosomes and hexosomes, and their use as versatile nanocarriers for different drug delivery applications. Additionally, the advantages of SLNs and their application in oral and pulmonary drug delivery are discussed with focus on the biological fates of these lipid nanocarriers in vivo. Despite the demonstrated advantages in in vitro and in vivo evaluations including preclinical studies, further investigations on improved understanding of the interactions of these nanoparticles with biological fluids and tissues of the target sites is necessary for efficient designing of drug nanocarriers and exploring potential clinical applications.

Silymarin-albumin nanoplex: Preparation and its potential application as an antioxidant in nervous system in vitro and in vivo

In this study, we formulated silymarin-HSA nanoplex and assayed its ability to reduce LPS-induced toxicity in vitro and in vivo. Silymarin molecules were encapsulated into HSA nanoplex and the loading efficiency and characterization of fabricated nanoplex were performed by using HPLC, TEM, SEM, DLS, FTIR analysis, and theoretical studies. Afterwards, their protective effect against LPS (20 µg/ml) -induced toxicity in SH-SY5Y cells was investigated by MTT, ROS, and apoptosis assays. For in vivo experiments, rats were pre-treated with either silymarin or silymarin -HSA nanoplex (200 mg/kg) orally for 3 days and at third day received LPS by IP at a dose of 0.5 mg/kg, 150 min before scarification followed by SOD and CAT activity assay. The formulation of silymarin-HSA nanoplex showed a spherical shape with an average diameter between 50 nm and 150 nm, hydrodynamic radius of 188.3 nm, zeta potential of -26.6 mV, and a drug loading of 97.3%. In LPS-treated cells, pretreatments with silymarin-HSA noncomplex recovered the cell viability and decreased the ROS level and corresponding apoptosis more significantly than free silymarin. In rats, it was also depicted that, silymarin-HSA noncomplex can increase the SOD and CAT activity in brain tissue at LPS-triggered oxidative stress model more significantly than the free counterpart. Therefore, nanoformulation of silymarin improved its capability to reduce LPS-induced oxidative stress by restoring cell viability and elevation of SOD and CAT activity in vitro and in vivo, respectively. In conclusion, formulation of silymarin may hold a great promise in the development of antioxidant agents.

Comparison of different aliphatic acid grafted N-trimethyl chitosan surface-modified nanostructured lipid carriers for improved oral kaempferol delivery

This study compared the in vitro and in vivo effects of different aliphatic acid grafted N-trimethyl chitosan (TMC) surface-modified nanostructured lipid carriers (NLC) by oral delivery. Medium-chain fatty acids, decylic acids (DA), and long-chain fatty acids, palmitic acids (PA) were selected as contrasting objects. TMC, DA grafted TMC (DA-TMC), and PA grafted TMC (PA-TMC) were successively synthesized. Kaempferol loaded NLC (KNLC), KNLC coated with DA-TMC (DA-TMC-KNLC) and PA-TMC (PA-TMC-KNLC) were fabricated, respectively. KNLC were subspherical in shape at nano-size limits. The particle size increased from 93.6 to 125.5 nm and the zeta potential changed from negative to positive due to surface-modification. The KNLC surface-modified with different aliphatic acid grafted TMC displayed a diverse release profiles at the simulative physiological environment, which contrasted that of KNLC. Pharmacokinetic studies demonstrated that the nanoparticles all could improve the AUC values and prolong blood retention times compared to that of kaempferol suspensions. Cell uptake and in situ intestinal perfusion experiments revealed that DA-TMC-KNLC and PA-TMC-KNLC could remarkably enhance cellular uptake of kaempferol into Caco-2 cells and drug absorption in each intestinal segment in comparison with KNLC, repectively. Wherein, DA-TMC-KNLC exhibits the greatest uptake and absorption efficiency as compared to kaempferol suspensions, KNLC and PA-TMC-KNLC. Collectively, DA-TMC surface-modified NLC might serve as a potential drug carrier for oral delivery of water-insoluble flavonoid ingredients.

Formulation Strategies for Enhancing the Bioavailability of Silymarin: The State of the Art

Silymarin, a mixture of flavonolignan and flavonoid polyphenolic compounds extractable from milk thistle (Silybum marianum) seeds, has anti-oxidant, anti-inflammatory, anti-cancer and anti-viral activities potentially useful in the treatment of several liver disorders, such as chronic liver diseases, cirrhosis and hepatocellular carcinoma. Equally promising are the effects of silymarin in protecting the brain from the inflammatory and oxidative stress effects by which metabolic syndrome contributes to neurodegenerative diseases. However, although clinical trials have proved that silymarin is safe at high doses (>1500 mg/day) in humans, it suffers limiting factors such as low solubility in water (<50 μg/mL), low bioavailability and poor intestinal absorption. To improve its bioavailability and provide a prolonged silymarin release at the site of absorption, the use of nanotechnological strategies appears to be a promising method to potentiate the therapeutic action and promote sustained release of the active herbal extract. The purpose of this study is to review the different nanostructured systems available in literature as delivery strategies to improve the absorption and bioavailability of silymarin.

Silymarin and silymarin nanoparticles guard against chronic unpredictable mild stress induced depressive-like behavior in mice: involvement of neurogenesis and NLRP3 inflammasome

BACKGROUND

The neuropathology of depression is quite complex. Thus, treatment failures are frequent with current antidepressants, raising the need for more effective ones.

AIMS

This study aimed to investigate the influence of silymarin on depressive-like behavior induced by chronic unpredictable mild stress (CUMS) and explore the underlying mechanisms.

METHODS

Silymarin was formulated as nanostructured lipid carriers (a lipid-based type of nanoparticle with the advantages of physical stability, good release profile, and targeted delivery). Mice were subjected to CUMS paradigm during 14 days. During this period, mice received silymarin (200 mg/kg, p.o.) per se or in its nanoparticle form or fluoxetine (10 mg/kg, p.o.). On the 15th day behavioral and biochemical parameters were analyzed.

RESULTS

Oral administration of silymarin (200 mg/kg), particularly in its nanoparticulate form, exerted an antidepressant-like effect, comparable with fluoxetine in mice, as demonstrated in the behavioral despair tests. Silymarin also reversed prefrontal cortical and hippocampal CUMS-induced oxidative stress and neuroinflammation. Furthermore, silymarin augmented neurotransmitter levels, enhanced neurogenesis and inhibited nod-like receptor protein 3 inflammasome activation. Silymarin nanoparticles were superior to silymarin in certain parameters probably due to significantly higher brain silybinin (the major active component of silymarin) concentration by 12.46 fold in the group administered silymarin nanoparticles compared with the mice which were administered silymarin per se.

CONCLUSIONS

The antidepressant-like effect of silymarin can be attributed to its antioxidant and anti-inflammatory effects as well as increased neurogenesis in the prefrontal cortex and hippocampus, which delineates silymarin, especially in nanoparticle form, as a promising strategy for treatment of depression.

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.

A systematic review on nanoencapsulation of food bioactive ingredients and nutraceuticals by various nanocarriers

Today, there is an ever-growing interest on natural food ingredients both by consumers and producers in the food industry. In fact, people are looking for those products in the market which are free from artificial and synthetic additives and can promote their health. These food bioactive ingredients should be formulated in such a way that protects them against harsh process and environmental conditions and safely could be delivered to the target organs and cells. Nanoencapsulation is a perfect strategy for this situation and there have been many studies in recent years for nanoencapsulation of food components and nutraceuticals by different technologies. In this review paper, our main goal is firstly to have an overview of nanoencapsulation techniques applicable to food ingredients in a systematic classification, i.e., lipid-based nanocarriers, nature-inspired nanocarriers, special-equipment-based nanocarriers, biopolymer nanocarriers, and other miscellaneous nanocarriers. Then, application of these cutting-edge nanocarriers for different nutraceuticals including phenolic compounds and antioxidants, natural food colorants, antimicrobial agents and essential oils, vitamins, minerals, flavors, fish oils and essential fatty acids will be discussed along with presenting some examples in each field.

Understanding the prospective of nano-formulations towards the treatment of psoriasis

Psoriasis is a consistently recurring, inflammatory, autoimmune disorder of the skin, affecting about 2-5% of the world population. Abundant therapeutic agents are accessible for the treatment of psoriasis. Nevertheless, none of them are entirely secure and effective to treat the disease without compromising patient compliance. Furthermore, already existing drugs are supposed to restrain the ailment and alleviate the sign and symptoms with no complete cure. However, they focus on restraining the disease and alleviating the symptoms without providing an absolute cure. Therefore there remains a vital challenge, to explore a new drug moiety or delivery system which could safely and effectively manage psoriasis without compromising patient compliance. Furthermore, conventional formulations offer reduced benefit/risk ratio of anti-psoriatic drugs, which limits the use of existing conventional formulations. Novel formulations based on nanocarriers are a promising prospect to overcome the limitation of conventional formulations by offering a reduction in dose, dosing frequency, dose-dependent, side effects with enhanced efficacy. Presently nano-formulations have gained widespread application for effective and safe treatment of psoriasis. The present review primarily focuses on conventional therapeutic strategy and recent advances in lipid-based, polymer-based and metallic nano-formulations of a variety of anti-psoriatic drugs. The practicability of various nanocarrier systems including liposomes, nanostructured lipid carriers, ethosomes, solid lipid nanoparticles, nanocapsules, micelles, dendrimers, gold nanoparticles and silver nanoparticles have been discussed in detail. The review also traces related patents to exemplify the role of various nanoparticles in psoriasis treatment. In a nutshell, nano-formulations remain established as a promising modality for treating psoriasis treatment as they propose better penetration, targeted delivery, enhanced safety, and efficacy.

In Vivo Fate of Biomimetic Mixed Micelles as Nanocarriers for Bioavailability Enhancement of Lipid-Drug Conjugates

The transformation of lipid-based nanovehicles into mixed micelles (MMs) upon lipolysis plays an indispensable role in enhancement of the oral bioavailability of poorly water-soluble drugs. Therefore, this study employs biomimetic MMs as functional vehicles to enhance the oral bioavailability of the lipid conjugates of a model drug silybin. The main objective is to explore the in vivo fate and underlying mechanisms of facilitated absorption by MMs. Pharmacokinetics in rats indicate bioavailability enhancement by 7-9 folds as compared to a fast-release silybin solid dispersion formulation. Confocal laser scanning microscopy reveals evidence of cellular uptake of integral MMs into the cytoplasm of both Caco-2 and Caco-2/HT29-MTX coculture cells lines. The recovery of a definite amount of prototype silybin but negligible or traces of lipid-silybin conjugates from the cells, as well as the limited trans-monolayer transport, confirms fast disruption of MMs and fast degradation of the conjugates as well. The MMs survive the gastrointestinal environment with relatively high integrity for about 4 h, and are found accumulating in intestinal villi surface layers in higher density but in lower density to the basolateral tissues. By scanning the organs, a small amount of integral MMs are observed to distribute mainly to the livers with peak time around 4-8 h. The total amount of lymphatic absorption monitored by cannulation is negligible. It is concluded that biomimetic MMs might be taken up by enterocytes and be digested there to release the prototype drug, which is further transported to the circulation, and only a limited amount of integral MMs could be absorbed into the circulation.

In vivo fate of lipid-silybin conjugate nanoparticles: Implications on enhanced oral bioavailability

Lipid-drug conjugates (LDCs) of a poorly soluble and poorly permeable drug silybin (SB) and lipids with different chain lengths (6C, 12C, 18C) are synthesized and formulated into solid lipid nanoparticles (SLNs). The in vivo fate of LDCs as well as SLNs is investigated by tracking either SB or LDCs or SLNs. LDCs are prone to be hydrolyzed by lipases either in simulated gastrointestinal media or in Caco-2 cell lines in a lipid chain length-dependent mode. The oral bioavailability of SB is enhanced by 5-7-fold in comparison with a fast-release formulation. No integral LDCs are detected in plasma confirms the readily degradable nature of LDCs. The absorption of LDCs by enteric epithelia and subsequent transportation into circulation might play a leading role in absorption enhancement, whereas the contribution of then M-cell pathway is not as remarkable. A shorter lipid chain favors earlier lipolysis and faster absorption along the intestine-to-circulation path.

Size-Dependent Translocation of Nanoemulsions via Oral Delivery

The in vivo translocation of nanoemulsions (NEs) was tracked by imaging tools with an emphasis on the size effect. To guarantee the accurate identification of NEs in vivo, water-quenching environment-responsive near-infrared fluorescent probes were used to label NEs. Imaging evidence confirmed prominent digestion in the gastrointestinal tract and oral absorption of integral NEs that survive digestion by enteric epithelia in a size-dependent way. In general, reducing particle size leads to slowed in vitro lipolysis and in vivo digestion, a prolonged lifetime in the small intestine, increased enteric epithelial uptake, and enhanced transportation to various organs. Histological examination revealed a pervasive distribution of smaller NEs (80 nm) into enterocytes and basolateral tissues, whereas bigger ones (550, 1000 nm) primarily adhered to villi surfaces. Following epithelial uptake, NEs are transported through the lymphatics with a fraction of approximately 3-6%, suggesting a considerable contribution of the lymphatic pathway to overall absorption. The majority of absorbed NEs were found 1 h post administration in the livers and lungs. A similar size dependency of cellular uptake and transmonolayer transport was confirmed in Caco-2 cell lines as well. In conclusion, the size-dependent translocation of integral NEs was confirmed with an absolute bioavailability of at least 6%, envisioning potential applications in oral delivery of labile entities.

Improving In Vivo Efficacy of Bioactive Molecules: An Overview of Potentially Antitumor Phytochemicals and Currently Available Lipid-Based Delivery Systems

Cancer is among the leading causes of morbidity and mortality worldwide. Many of the chemotherapeutic agents used in cancer treatment exhibit cell toxicity and display teratogenic effect on nontumor cells. Therefore, the search for alternative compounds which are effective against tumor cells but reduce toxicity against nontumor ones is of great importance in the progress or development of cancer treatments. In this sense, scientific knowledge about relevant aspects of nutrition intimately involved in the development and progression of cancer progresses rapidly. Phytochemicals, considered as bioactive ingredients present in plant products, have shown promising effects as potential therapeutic/preventive agents on cancer in several in vitro and in vivo assays. However, despite their bioactive properties, phytochemicals are still not commonly used in clinical practice due to several reasons, mainly attributed to their poor bioavailability. In this sense, new formulation strategies are proposed as carriers to improve their bioefficacy, highlighting the use of lipid-based delivery systems. Here, we review the potential antitumoral activity of the bioactive compounds derived from plants and the current studies carried out in animal and human models. Furthermore, their association with lipids as a formulation strategy to enhance their efficacy in vivo is also reported. The development of high effective bioactive supplements for cancer treatment based on the improvement of their bioavailability goes through this association.

Lipid-associated oral delivery: Mechanisms and analysis of oral absorption enhancement

The majority of newly discovered oral drugs are poorly water soluble, and co-administration with lipids has proven effective in significantly enhancing bioavailability of some compounds with low aqueous solubility. Yet, lipid-based delivery technologies have not been widely employed in commercial oral products. Lipids can impact drug transport and fate in the gastrointestinal (GI) tract through multiple mechanisms including enhancement of solubility and dissolution kinetics, enhancement of permeation through the intestinal mucosa, and triggering drug precipitation upon lipid emulsion depletion (e.g., by digestion). The effect of lipids on drug absorption is currently not quantitatively predictable, in part due to the multiple complex dynamic processes that can be impacted by lipids. Quantitative mechanistic analysis of the processes significant to lipid system function and overall impact on drug absorption can aid in the understanding of drug-lipid interactions in the GI tract and exploitation of such interactions to achieve optimal lipid-based drug delivery. In this review, we discuss the impact of co-delivered lipids and lipid digestion on drug dissolution, partitioning, and absorption in the context of the experimental tools and associated kinetic expressions used to study and model these processes. The potential benefit of a systems-based consideration of the concurrent multiple dynamic processes occurring upon co-dosing lipids and drugs to predict the impact of lipids on drug absorption and enable rational design of lipid-based delivery systems is presented.

Sodium dodecyl sulfate/β-cyclodextrin vesicles embedded in chitosan gel for insulin delivery with pH-selective release

In an answer to the challenge of enzymatic instability and low oral bioavailability of proteins/peptides, a new type of drug-delivery vesicle has been developed. The preparation, based on sodium dodecyl sulfate (SDS) and β-cyclodextrin (β-CD) embedded in chitosan gel, was used to successfully deliver the model drug-insulin. The self-assembled SDS/β-CD vesicles were prepared and characterized by particle size, zeta potential, appearance, microscopic morphology and entrapment efficiency. In addition, both the interaction of insulin with vesicles and the stability of insulin loaded in vesicles in the presence of pepsin were investigated. The vesicles were crosslinked into thermo-sensitive chitosan/β-glycerol phosphate solution for an in-situ gel to enhance the dilution stability. The in vitro release characteristics of insulin from gels in media at different pH values were investigated. The insulin loaded vesicles–chitosan hydrogel (IVG) improved the dilution stability of the vesicles and provided pH-selective sustained release compared with insulin solution–chitosan hydrogel (ISG). In vitro, IVG exhibited slow release in acidic solution and relatively quick release in neutral solutions to provide drug efficacy. In simulated digestive fluid, IVG showed better sustained release and insulin protection properties compared with ISG. Thus IVG might improve the stability of insulin during its transport in vivo and contribute to the bioavailability and therapeutic effect of insulin.

Key Considerations in Designing Oral Drug Delivery Systems for Dogs

The present review discusses the pharmaceutical impact of the anatomy and physiology of the canine gastrointestinal tract to provide a comprehensive guide to the theories and challenges associated with the development of oral drug delivery systems for dogs. Novel pharmaceutical technologies applied to veterinary drugs are discussed indicating the advantages and benefits for animals. There are currently immense research and development efforts being funneled into novel canine health products. Such products are being used to overcome limitations of drugs that display site-dependent absorption or possess poor biopharmaceutical properties. Techniques that are employed to increase bioavailability of the Biopharmaceutics Classification System class II drugs are discussed in this article. Furthermore, an overview of palatable oral formulations for dog care is provided as an approach to easy administration. In vitro and in vivo evaluation and correlation of oral drug formulations in dogs are also addressed. This article assesses the outlook of canine oral drug development recognizing substantial growth forecasts of the dog care market.

Utilization of nanoemulsions to enhance bioactivity of pharmaceuticals, supplements, and nutraceuticals: Nanoemulsion delivery systems and nanoemulsion excipient systems

INTRODUCTION

The efficacy of many hydrophobic bioactives (pharmaceuticals, supplements, and nutraceuticals) is limited due to their relatively low or highly variable bioavailability. Nanoemulsions consisting of small lipid droplets (r < 100 nm) dispersed in water can be designed to improve bioavailability.

AREAS COVERED

The major factors limiting the oral bioavailability of hydrophobic bioactive agents are highlighted: bioaccessibility, absorption and transformation. Two nanoemulsion-based approaches to control these processes and improve bioavailability are discussed: nanoemulsion delivery systems (NDS) and nanoemulsion excipient systems (NES). In NDS, hydrophobic bioactives are dissolved within the lipid phase of oil-in-water nanoemulsions. In NES, the bioactives are present within a conventional drug, supplement, or food, which is consumed with an oil-in-water nanoemulsion. Examples of NDS and NES utilization to improve bioactive bioavailability are given.

EXPERT OPINION

Considerable progress has been made in nanoemulsion design, fabrication, and testing. This knowledge facilitates the design of new formulations to improve the bioavailability of pharmaceuticals, supplements, and nutraceuticals. NDS and NES must be carefully designed based on the major factors limiting the bioavailability of specific bioactives. Research is still required to ensure these systems are commercially viable, and to demonstrate their safety and efficacy using animal and human feeding studies.

Enhanced oral bioavailability of silymarin using liposomes containing a bile salt: preparation by supercritical fluid technology and evaluation in vitro and in vivo

The aim of this investigation was to develop a procedure to improve the dissolution and bioavailability of silymarin (SM) by using bile salt-containing liposomes that were prepared by supercritical fluid technology (ie, solution-enhanced dispersion by supercritical fluids [SEDS]). The process for the preparation of SM-loaded liposomes containing a bile salt (SM-Lip-SEDS) was optimized using a central composite design of response surface methodology with the ratio of SM to phospholipids (w/w), flow rate of solution (mL/min), and pressure (MPa) as independent variables. Particle size, entrapment efficiency (EE), and drug loading (DL) were dependent variables for optimization of the process and formulation variables. The particle size, zeta potential, EE, and DL of the optimized SM-Lip-SEDS were 160.5 nm, −62.3 mV, 91.4%, and 4.73%, respectively. Two other methods to produce SM liposomes were compared to the SEDS method. The liposomes obtained by the SEDS method exhibited the highest EE and DL, smallest particle size, and best stability compared to liposomes produced by the thin-film dispersion and reversed-phase evaporation methods. Compared to the SM powder, SM-Lip-SEDS showed increased in vitro drug release. The in vivo AUC_0−t of SM-Lip-SEDS was 4.8-fold higher than that of the SM powder. These results illustrate that liposomes containing a bile salt can be used to enhance the oral bioavailability of SM and that supercritical fluid technology is suitable for the preparation of liposomes.

Nanostructured lipid carriers used for oral delivery of oridonin: an effect of ligand modification on absorption

Oridonin (Ori) is a natural compound with notable anti-inflammation and anti-cancer activities. However, therapeutic use of this compound is limited by its poor solubility and low bioavailability. Here a novel biotin-modified nanostructured lipid carrier (NLC) was developed to enhance the bioavailability of Ori. The effect of ligand (biotin) modification on oral absorption of Ori encapsulated in NLCs was also explored. Ori-loaded NLCs (Ori-NLCs) were prepared by the melt dispersion-high pressure homogenization method. Biotin modification of Ori-NLCs was achieved by EDC and NHS in aqueous phase. The obtained biotin-decorated Ori-NLCs (Bio-Ori-NLCs) were 144.9nm in size with an entrapment efficiency of 49.54% and a drug load of 4.81%. Oral bioavailability was enhanced by use of Bio-Ori-NLCs with a relative bioavailability of 171.01%, while the value of non-modified Ori-NLCs was improved to 143.48%. Intestinal perfusion showed that Ori solution unexpectedly exhibited a moderate permeability, indicating that permeability was not a limiting factor of Ori absorption. Ori could be rapidly metabolized that was the main cause of low bioavailability. However, there was a difference in the enhancement of bioavailability between Bio-Ori-NLCs and conventional NLCs. Although severe lipolyses happened both on Bio-Ori-NLCs and non-modified NLCs, the performance of Bio-Ori-NLCs in the bioavailability improvement was more significant. Overall, Bio-Ori-NLCs can further promote the oral absorption of Ori by a ligand-mediated active transport. It may be a promising carrier for the oral delivery of Ori.

Effects of PEGylated lipid nanoparticles on the oral absorption of one BCS II drug: a mechanistic investigation

Lipid nanocarriers are becoming a versatile platform for oral delivery of lipophilic drugs. In this article, we aimed to explore the gastrointestinal behaviors of lipid nanoparticles and the effect of PEGylation on oral absorption of fenofibrate (FN), a Biopharmaceutics Classification System (BCS) II model drug. FN-loaded PEGylated lipid nanoparticles (FN-PLNs) were prepared by the solvent-diffusion method and characterized by particle size distribution, morphology, Fourier transform infrared spectroscopy, and drug release. Lipolytic experiments were performed to assess the resistance of lipid nanoparticles against pancreatic lipase. Pharmacokinetics was evaluated in rats after oral administration of FN preparations. The obtained FN-PLNs were 186.7 nm in size with an entrapment efficiency of >95%. Compared to conventional lipid nanoparticles, PLNs exhibited slower drug release in the lipase-containing medium, strikingly reduced mucin binding, and suppressed lipolysis in vitro. Further, oral absorption of FN was significantly enhanced using PLNs with relative bioavailability of 123.9% and 157.0% to conventional lipid nanoparticles and a commercial formulation (Lipanthyl^®), respectively. It was demonstrated that reduced mucin trapping, suppressed lipolysis, and/or improved mucosal permeability were responsible for increased oral absorption. These results facilitated a better understanding of the in vivo fate of lipid nanoparticles, and suggested the potential of PLNs as oral carriers of BCS II drugs.