Lipids and lipid-based formulations: optimizing the oral delivery of lipophilic drugs

Controlled lipid digestion in the development of functional and personalized foods for a tailored delivery of dietary fats

In recent decades, obesity and its associated health issues have risen dramatically. The COVID-19 pandemic has further exacerbated this trend, underscoring the pressing need for new strategies to manage weight. Functional foods designed to modulate lipid digestion and absorption rates and thereby reduce the assimilation of dietary fats have gained increasing attention in food science as a potentially safer alternative to weight-loss medications. This review provides insights into controlled lipid digestion and customized delivery of fats. The first section introduces basic concepts of lipid digestion and absorption in the human gastrointestinal tract. The second section discusses factors regulating lipid digestion and absorption rates, as well as strategies for modulating lipid assimilation from food. The third section focuses on applications of controlled lipid digestion in developing personalized foods designed for specific consumer groups, with particular emphasis on two target populations: overweight individuals and infants.

Rapeseed oleosomes facilitate intestinal lymphatic delivery and oral bioavailability of cannabidiol

Due to high lipophilicity and extensive first-pass metabolic loss, cannabidiol (CBD) has low oral bioavailability. Co-administration of CBD and long-chain lipids facilitates the intestinal lymphatic delivery, resulting in higher systemic bioavailability, as well as high levels of the drug within the intestinal lymphatic system. However, despite previous attempts with various lipid-based formulations, the oral bioavailability of CBD is still limited. In this work, we have developed a novel formulation of CBD based on natural rapeseed oleosomes. In vivo studies in rats demonstrated that oral administration of CBD-loaded rapeseed oleosomes leads to substantially higher oral bioavailability and intestinal lymphatic targeting of CBD in comparison with rapeseed oil or artificial emulsion made of rapeseed oil and lecithin. In vitro mechanistic assessments, including in vitro lipolysis and peroxide value determination suggest that the lower oxidative state of the oil in oleosomes in comparison to crude oil or artificial emulsion is likely to be the main factor responsible for the superior performance of the CBD-loaded rapeseed oleosomes in vivo. Although further investigation will be needed, the data suggest that natural seeds-derived oleosomes can be used as a promising lipid-based drug delivery platform promoting the bioavailability and lymphatic delivery of lipophilic drugs.

Lipidic drug delivery systems are responsive to the human microbiome

In vitro and in vivo tests for therapeutic agents are typically conducted in sterile environments, but many target areas for drug delivery are home to thousands of microbial species. Here, we examine the behaviour of lipidic nanomaterials after exposure to representative strains of four bacterial species found in the gastrointestinal tract and skin. Small angle X-ray scattering measurements show that the nanostructure of monoolein cubic and inverse hexagonal phases are transformed, respectively, into inverse hexagonal and inverse micellar cubic phases upon exposure to a strain of live Staphylococcus aureus often present on skin and mucosa. Further investigation demonstrates that enzymatic hydrolysis and cell membrane lipid transfer are both likely responsible for this effect. The structural responses to S. aureus are rapid and significantly reduce the rate of drug release from monoolein-based nanomaterials. These findings are the first to demonstrate how a key species in the live human microbiome can trigger changes in the structure and drug release properties of lipidic nanomaterials. The effect appears to be strain specific, varies from patient to patient and body region to body region, and is anticipated to affect the bioapplication of monoglyceride-based formulations.

Delivery of imiquimod to intestinal lymph nodes following oral administration

Intestinal lymph nodes are involved in the progression of colorectal cancer (CRC). Tumours suppress the activation of dendritic cells (DCs) in draining lymph nodes, diminishing anti-cancer immune response. Imiquimod (IMQ) facilitates DCs activation via toll-like receptor 7, suggesting that targeted delivery of IMQ to intestinal lymph nodes can improve the treatment of CRC. This study aims to enhance the delivery of IMQ to intestinal lymph nodes by a highly lipophilic prodrug approach. Amide prodrugs were synthesised by conjugating IMQ with saturated and unsaturated medium- to long-chain fatty acids. Their potential for intestinal lymphatic transport was assessed by their affinity to chylomicrons and solubility in long-chain triglycerides. Further selection of prodrug candidates was determined by resistance to enzymatic hydrolysis in intestinal lumen and release of IMQ in the lymphatics using fasting state simulated intestinal fluid supplemented with esterases, brush border enzyme vesicles and plasma. Key pharmacokinetic parameters and biodistribution in rats were assessed for the most promising compounds, prodrugs 5 and 8. The plasma concentration-time profile of IMQ following oral administration of the prodrugs was less erratic in comparison to the administration of unmodified IMQ. The lymph-to-plasma ratios of IMQ concentration increased 1.9- and 1.7-fold using prodrugs 5 and 8 in comparison to administration of unmodified IMQ, respectively. Importantly, the average concentration of IMQ in mesenteric lymph nodes (MLN) was 11.2- and 7.6-fold higher than in plasma following the administration of prodrugs 5 and 8, respectively. Additionally, the non-specific wide distribution of IMQ into various organs and tissues was reduced with prodrugs. This work suggests that the highly lipophilic prodrug approach can efficiently deliver IMQ to intestinal lymphatics. In addition, this study demonstrates the feasibility of an amide prodrug approach for intestinal lymphatic targeting.

Development of polymer-encapsulated microparticles of a lipophilic API-IL and its lipid based formulations for enhanced solubilisation

Active Pharmaceutical Ingredient-Ionic liquids (API-ILs) have the potential to improve the bioavailability of BCS Class IV Drugs. However, the problematic physical handling properties of room temperature API-ILs have impaired clinical and commercial exploitation to date. Lipid-based formulations (LBFs) are used to improve the absorption of drugs with limited bioavailability. Nonetheless, LBFs face limitations such as low drug loading capacity and sub-par physical stability. A platform for transforming API-ILs into solid forms at high loadings via spray encapsulation with polymers has been developed and previously demonstrated for hydrophilic API-ILs. The current work demonstrates that this platform technology can be applied to a lipophilic API-IL of the BCS Class IV API, chlorpromazine, and to multi-component solutions comprising API-IL and a LBF. Furthermore, solidification of a type IIIB, liquid LBF was achieved via spray encapsulation with cellulose- and methacrylate- based polymers for the first time. The spray-encapsulated formulations had excellent physical handling properties, and successfully eluted the API-IL in aqueous media. The chlorpromazine release profiles from the API-IL, the API-IL containing LBF, and the solidified formulations, were evaluated in vitro using phosphate buffer (pH 6.8) and fasted state simulated intestinal fluid (FaSSIF). Spray-encapsulated formulations exhibited improved release profiles compared to the liquid formulations. Overall, these findings indicate that phase-separated, polymeric, solid formulations of liquid API forms represent a promising platform technology for developing oral solid dosage forms of poorly bioavailable drugs.

Synergistic Combination of Oral Transcytotic Nanomedicine and Histone Demethylase Inhibitor for Enhanced Cancer Chemoimmunotherapy

Oral nanomedicines present a preferable avenue for cancer immunotherapy, but their efficacy is limited by gastrointestinal absorption challenges, tumor physiopathologic barriers, and immune evasion mechanisms. Here, we present an approach that combines an oral transcytotic doxorubicin (DOX) nanomedicine with the histone demethylase inhibitor 5-carboxy-8-hydroxyquinoline (IOX1), thereby enabling synergistic chemoimmunotherapy. We demonstrate that IOX1 significantly augments the transcytosis capabilities of DOX-loaded poly(2-(N-oxide-N,N-diethylamino)ethylmethacrylate)-poly(ε-caprolactone) micelles (OPDOX), promoting their transcellular transport across various cellular barriers (villus, endothelial, and tumor cells), thus improving oral adsorption, vascular extravasation, and tumor penetration. Furthermore, IOX1 sensitizes chemotherapy to potentiate DOX-induced immunogenic cell death and downregulates programmed cell death-ligand 1 to disrupt the immune checkpoint mechanism, synergistically boosting robust antitumor immune responses. Consequently, orally administered OPDOX in combination with IOX1 efficiently inhibits CT26 tumor growth, highlighting the significant potential for enhancing the efficacy of oral nanomedicines in cancer chemoimmunotherapy.

Alahmari A, A. Alqabbani A, Aldayel AM. Exploring the landscape of Lipid Nanoparticles (LNPs): A comprehensive review of LNPs types and biological sources of lipids

Lipid nanoparticles (LNPs) have emerged as promising carriers for delivering therapeutic agents, including mRNA-based immunotherapies, in various biomedical applications. The use of LNPs allows for efficient delivery of drugs, resulting in enhanced targeted delivery to specific tissues or cells. These LNPs can be categorized into several types, including liposomes, solid lipid nanoparticles, nanostructured lipid carriers, and lipid-polymer hybrid nanoparticles. The preparation of LNPs involves the manipulation of their structural, dimensional, compositional, and physical characteristics via the use of different methods in the industry. Lipids used to construct LNPs can also be derived from various biological sources, such as natural lipids extracted from plants, animals, or microorganisms. This review dives into the different types of LNPs and their preparation methods. More importantly, it discusses all possible biological sources that are known to supply lipids for the creation of LNPs. Natural lipid reservoirs have surfaced as promising sources for generating LNPs. The use of LNPs in drug delivery is expected to increase significantly in the coming years. Herein, we suggest some environmentally friendly and biocompatible sources that can produce lipids for future LNPs production.

In situ customized apolipoprotein B48-enriched protein corona enhances oral gene delivery of chitosan-based nanoparticles

The formation of protein corona (PC) is important for promoting the in vivo delivery of nanoparticles (NPs). However, PC formed in the physiological environment of oral delivery is poorly understood. Here, we engineered seven types of trimethyl chitosan-cysteine (TC) NPs, with distinct molecular weights, quaternization degrees, and thiolation degrees, to deeply investigate the influence of various PC formed in the physiological environment of oral delivery on in vivo gene delivery of polymeric NPs, further constructing the relationship between the surface characteristics of NPs and the efficacy of oral gene delivery. Our findings reveal that TC7 NPs, with high molecular weight, moderate quaternization, and high sulfhydryl content, modulate PC formation in the gastrointestinal tract, thereby reducing particle size and promoting oral delivery of gene loaded TC7 NPs. Orally delivered TC7 NPs target macrophages by in situ adsorption of apolipoprotein (Apo) B48 in intestinal tissue, leading to the improved in vivo antihepatoma efficacy via the natural tumor homing ability of macrophages. Our results suggest that efficient oral delivery of genes can be achieved through an in situ customized ApoB48-enriched PC, offering a promising modality in treating macrophage-related diseases.

Demystifying the potential of lipid-based nanocarriers in targeting brain malignancies

Drug targeting for brain malignancies is restricted due to the presence of the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB), which act as barriers between the blood and brain parenchyma. Certainly, the limited therapeutic options for brain malignancies have made notable progress with enhanced biological understanding and innovative approaches, such as targeted therapies and immunotherapies. These advancements significantly contribute to improving patient prognoses and represent a promising shift in the landscape of brain malignancy treatments. A more comprehensive understanding of the histology and pathogenesis of brain malignancies is urgently needed. Continued research focused on unraveling the intricacies of brain malignancy biology holds the key to developing innovative and tailored therapies that can improve patient outcomes. Lipid nanocarriers are highly effective drug delivery systems that significantly improve their solubility, bioavailability, and stability while also minimizing unwanted side effects. Surface-modified lipid nanocarriers (liposomes, niosomes, solid lipid nanoparticles, nanostructured lipid carriers, lipid nanocapsules, lipid-polymer hybrid nanocarriers, lipoproteins, and lipoplexes) are employed to improve BBB penetration and uptake through various mechanisms. This systematic review illuminates and covers various topics related to brain malignancies. It explores the different methods of drug delivery used in treating brain malignancies and delves into the benefits, limitations, and types of brain-targeted lipid-based nanocarriers. Additionally, this review discusses ongoing clinical trials and patents related to brain malignancy therapies and provides a glance into future perspectives for treating this condition.

The interaction of a self-assembled nanoparticle and a lipid membrane: Binding, disassembly and re-distribution

Here we report a detailed study of the interactions of nanoparticles, formed by the self-assembly of cholesterol-containing porphyrins, with lipid membranes. We show that the interaction is a two-step process: first, the docking and fusion, then, the redistribution of the building blocks of the self-assembled nanoparticles (SANs henceforth). Analysis of the binding and structural data is consistent with the docking step being driven by a multivalence cooperative effect and with the formation of SAN aggregates on the membrane, whilst the solubility of the cholesterol anchor in the membrane is key to both the fusion and redistribution of the SANs building blocks. The tendency of the SAN to aggregate in the membrane helps explain the photosensitizer properties of the SANs, essential to their anti-microbial activity. The solubility of the cholesteryl anchors drives fusion to the membrane and de-assembly of the SAN, explaining the capability of the SANs to deliver therapeutic cargos at the lipid interface. The subsequent redistribution of the SANs building blocks offer a plausible pathway to body clearance that is not immediately available to hard nanoparticles. These properties, and the modularity of the synthesis, point to the SANs being an excellent platform for the development of nanomedicines. An unexpected consequence of unraveling the mechanism of membrane interaction of these SANs is that it allows us to derive a value of the free energy of binding of cholesterol (the membrane anchor of the SAN building blocks) to a lipid membrane, that is consistent with the literature values. This is an additional property that can be exploited to determine the affinity of a variety of membrane anchors to membranes of various compositions.

Glyceroniosomes for enhanced intestinal absorption of hydrochlorothiazide and lisinopril in their fixed dose combination

The objective was to investigate the effect of co-administration of hydrochlorothiazide and lisinopril as fixed dose combination on their intestinal absorption. The scope was extended to enhance intestinal absorption of both drugs. In situ rabbit intestinal absorption through the duodenum and jejuno-ileum was used to monitor membrane permeability of both drugs when perfused alone or in combination. Niosomes containing glycerols (glyceroniosomes) were loaded with both drugs. Glyceroniosomes comprised Span 60 or Tween 40 in combination with cholesterol and glycerol were prepared by bath sonication. Glyceroniosomes were characterized with respect to vesicle size, drug entrapment efficiency and were examined using transmission electron microscope (TEM). The prepared vesicles were nanosized spherical vesicles with average size of 202.4 nm and 108.8 nm for span free and span containing glyceroniosomes, respectively. The recorded Zeta potential values suggested good stability of the prepared formulations. Intestinal absorption studies reflected incomplete absorption of hydrocholothiazide and lisinopril correlating with their categorization as class IV and III drugs, respectively. Co-perfusion of both drugs reduced the intestinal absorption of lisinopril. Simultaneous encapsulation in glyceroniosomes enhanced the intestinal absorption of both drugs. Tween based systems were more efficient. The study introduced glyceroniosomes as carriers of simultaneous delivery of hydrochlorothiazide and lisinopril.

Intestinal Lymphatic Biology, Drug Delivery, and Therapeutics: Current Status and Future Directions

Historically, the intestinal lymphatics were considered passive conduits for fluids, immune cells, dietary lipids, lipid soluble vitamins, and lipophilic drugs. Studies of intestinal lymphatic drug delivery in the late 20th century focused primarily on the drugs' physicochemical properties, especially high lipophilicity, that resulted in intestinal lymphatic transport. More recent discoveries have changed our traditional view by demonstrating that the lymphatics are active, plastic, and tissue-specific players in a range of biological and pathological processes, including within the intestine. These findings have, in turn, inspired exploration of lymph-specific therapies for a range of diseases, as well as the development of more sophisticated strategies to actively deliver drugs or vaccines to the intestinal lymph, including a range of nanotechnologies, lipid prodrugs, and lipid-conjugated materials that "hitchhike" onto lymphatic transport pathways. With the increasing development of novel therapeutics such as biologics, there has been interest in whether these therapeutics are absorbed and transported through intestinal lymph after oral administration. Here we review the current state of understanding of the anatomy and physiology of the gastrointestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. We summarize the current state-of-the-art approaches to deliver drugs and quantify their uptake into the intestinal lymphatic system. Finally, and excitingly, we discuss recent examples of significant pharmacokinetic and therapeutic benefits achieved via intestinal lymphatic drug delivery. We also propose approaches to advance the development and clinical application of intestinal lymphatic delivery strategies in the future. SIGNIFICANCE STATEMENT: This comprehensive review details the understanding of the anatomy and physiology of the intestinal lymphatic system in health and disease, with a focus on aspects relevant to drug delivery. It highlights current state-of-the-art approaches to deliver drugs to the intestinal lymphatics and the shift toward the use of these strategies to achieve pharmacokinetic and therapeutic benefits for patients.

Stiff-Soft Hybrid Biomimetic Nano-Emulsion for Targeted Liver Delivery and Treatment of Early Nonalcoholic Fatty Liver Disease

Background: Nonalcoholic fatty liver disease (NAFLD) poses a risk for numerous metabolic diseases. To date, the U.S. Food and Drug Administration has not yet approved any medications for the treatment of NAFLD, for which developing therapeutic drugs is urgent. Dihydromyricetin (DMY), the most abundant flavonoid in vine tea, has been shown to be hepatoprotective. Its application was limited by low bioavailability in vivo; Methods: In order to improve the bioavailability of DMY and achieve liver-targeted delivery, we designed a DMY-loaded stiff-soft hybrid biomimetic nano drug delivery system (DMY-hNE). The in vivo absorption, distribution, pharmacokinetic profiles, and anti-NAFLD efficacy of DMY-hNE were studied; Results: DMY-hNE was composed of a stiff core and soft shell, which led to enhanced uptake by gastrointestinal epithelial cells and increased penetration of the mucus barrier, thus improving the in vivo absorption, plasma DMY concentration, and liver distribution versus free DMY. In an early NAFLD mouse model, DMY-hNE effectively ameliorated fatty lesions accompanied with reduced lipid levels and liver tissue inflammation; Conclusions: These findings suggested that DMY-hNE is a promising platform for liver drug delivery and treatment of hepatopathy.

Computational assessment of lipid facilitated membrane permeation of vancomycin using force-probe molecular dynamic simulation

In this study the efficacy of different edible lipids for drug permeation enhancement of vancomycin through biological membrane was investigated using molecular dynamic simulation. In this regard, at first the ability of the lipids for complex formation with the drug was evaluated for number of most common edible lipids including tripalmitin (TPA), trimyristin (TMY), labrafil (LAB), glycerol monostearate (GMS), glycerol monooleate (GMO), Distearoylphosphorylethanolamine (DSPE), dipalmitoylphosphatidylethanolamine (DPPE), Dipalmitoylphosphatidylcholine (DPPC), cholesterol (CL), stearic acid (SA), palmitic acid (PA) and oleic acid (OA). Then the complexes were pulled thorough a bilayer membrane while the changes in force were probed. The results showed that besides the SA, PA and OA the other examined lipids were able to perform a perfect molecular complex with the drug. Also the results of pulling simulation revealed that the least of force was needed for drug transmittance through the membrane when it was covered by LAB, TMY and DSPE. These results indicated that these lipids can be the excellent materials of choice as permeation enhancer for preparing a proper oral formulation of vancomycin.Communicated by Ramaswamy H. Sarma.

Contrasting the pharmacokinetic performance and gut microbiota effects of an amorphous solid dispersion and lipid nanoemulsion for a poorly water-soluble anti-psychotic

Increasing attention is being afforded to understanding the bidirectional relationship that exists between oral drugs and the gut microbiota. Often overlooked, however, is the impact that pharmaceutical excipients exert on the gut microbiota. Subsequently, in this study, we contrasted the pharmacokinetic performance and gut microbiota interactions between two commonly employed formulations for poorly soluble compounds, namely 1) an amorphous solid dispersion (ASD) stabilised by poly(vinyl pyrrolidone) K-30, and 2) a lipid nanoemulsion (LNE) comprised of medium chain glycerides and lecithin. The poorly soluble antipsychotic, lurasidone, was formulated with ASD and LNE due to its rate-limiting dissolution, poor oral bioavailability, and significant food effect. Both the ASD and LNE were shown to facilitate lurasidone supersaturation within in vitro dissolution studies simulating the gastrointestinal environment. This translated into profound improvements in oral pharmacokinetics in rats, with the ASD and LNE exerting comparable ∼ 2.5-fold improvements in lurasidone bioavailability, compared to the pure drug. The oral formulations imparted contrasting effects on the gut microbiota, with the LNE depleting the richness and abundance of the microbial ecosystem, as evidenced through reductions in alpha diversity (Chao1 index) and operational taxonomical units (OTUs). In contrast, the ASD exerted a 'gut neutral' effect, whereby a mild enrichment of alpha diversity and OTUs was observed. Importantly, this suggests that ASDs are effective solubility-enhancing formulations that can be used without comprising the integrity of the gut microbiota - an integral consideration in the treatment of mental health disorders, such as schizophrenia, due to the role of the gut microbiota in regulating mood and cognition.

Benefits of combining supersaturating and solubilizing formulations - Is two better than one?

A variety of enabling formulations has been developed to address poor oral drug absorption caused by insufficient dissolution in the gastrointestinal tract. As the in vivo performance of these formulations is a result of a complex interplay between dissolution, digestion and permeation, development of suitable in vitro assays that captures these phenomena are called for. The enabling-absorption (ENA) device, consisting of a donor and receiver chamber separated by a semipermeable membrane, has successfully been used to study the performance of lipid-based formulations. In this work, the ENA device was prepared with two different setups (a Caco-2 cell monolayer and an artificial lipid membrane) to study the performance of a lipid-based formulation (LBF), an amorphous solid dispersion (ASD) and the potential benefit of combining the two formulation strategies. An in vivo pharmacokinetic study in rats was performed to evaluate the in vitro-in vivo correlation. In the ENA, high drug concentrations in the donor chamber did not translate to a high mass transfer, which was particularly evident for the ASD as compared to the LBF. The solubility of the polymer used in the ASD was strongly affected by pH-shifts in vitro, and the ph_dependence resulted in poor in vivo performance of the formulation. The dissolution was however increased in vitro when the ASD was combined with a blank lipid-based formulation. This beneficial effect was also observed in vivo, where the drug exposure of the ASD increased significantly when the ASD was co-administered with the blank LBF. To conclude, the in vitro model managed to capture solubility limitations and strategies to overcome these for one of the formulations studied. The correlation between the in vivo exposure of the drug exposure and AUC in the ENA was good for the non pH-sensitive formulations. The deconvoluted pharmacokinetic data indicated that the receiver chamber was a better predictor for the in vivo performance of the drug, however both chambers provided valuable insights to the observed outcome in vivo. This shows that the advanced in vitro setting used herein successfully could explain absorption differences of highly complex formulations.

Impact of oil type on the development and oral bioavailability of self-nanoemulsifying drug delivery systems containing simvastatin

The aim of this work is to develop and evaluate self-nanoemulsifying drug delivery systems (SNEDDS) containing simvastatin to increase its oral bioavailability. Formulation EO 5 (Ethyl oleate 9.3% w/w: Tween 80 49.4% w/w: Propylene glycol 39.3% w/w) and Formulation CL 14 (Clove oil 54.3% w/w: Tween 80 34.4% w/w: Transcutol-P 9.3% w/w) were thoroughly studied. They showed emulsification time less than 1 min, droplet size in the nanometric range, and almost a complete drug release after 2 h. The in-vitro dissolution profile of both formulations was found to be significant in comparison to the pure drug in pH 1.2 and 7.4 buffers (P < 0.0001). Furthermore, they demonstrated superior anti-hyperlipidemic activity in comparison to simvastatin suspension (10 mg/kg/day). In order to investigate the impact of oil type on oral bioavailability, the selected formulations have been examined in terms of the in-vivo pharmacokinetic study, and formulation EO 5 was found to have higher bioavailability. After oral administration of a single dose (40 mg/kg) of simvastatin-loaded SNEDDS (CL14 and EO 5), a 1.5-fold and 1.95-fold increase in bioavailability were observed, respectively, as compared to simvastatin suspension. Hence, the results indicated that the developed SNEDDS could enhance the therapeutic efficacy and oral bioavailability of simvastatin.

Enteral Route Nanomedicine for Cancer Therapy

With the in-depth knowledge of the pathological and physiological characteristics of the intestinal barrier-portal vein/intestinal lymphatic vessels-systemic circulation axis, oral targeted drug delivery is frequently being renewed. With many advantages, such as high safety, convenient administration, and good patient compliance, many researchers have begun to explore targeted drug delivery from intravenous injections to oral administration. Over the past few decades, the fields of materials science and nanomedicine have produced various drug delivery platforms that hold great potential in overcoming the multiple barriers associated with oral drug delivery. However, the oral transport of particles into the systemic circulation is extremely difficult due to immune rejection and biochemical invasion in the intestine, which limits absorption and entry into the bloodstream. The feasibility of the oral delivery of targeted drugs to sites outside the gastrointestinal tract (GIT) is unknown. This article reviews the biological barriers to drug absorption, the in vivo fate and transport mechanisms of drug carriers, the theoretical basis for oral administration, and the impact of carrier structural evolution on oral administration to achieve this goal. Finally, this article reviews the characteristics of different nano-delivery systems that can enhance the bioavailability of oral therapeutics and highlights their applications in the efficient creation of oral anticancer nanomedicines.

Evaluation of the pharmacokinetics, chylomicron inhibition, and toxicity of colchicine in rats given low doses

Colchicine (COL) is known for its ability to inhibit the formation of intestinal chylomicrons and has been utilized as a non-surgical tool to explore drug absorption via the intestinal lymphatics. However, there is limited understanding of its pharmacokinetics and its relationship to effect and toxicity with the doses used. This study aimed to provide comprehensive COL pharmacokinetic data and correlate it with the lymphatic-blocking and toxicological effects of low-doses. Male Sprague-Dawley rats with jugular-vein cannulation (JVC) received 0.1 to 0.5 mg/kg COL via oral, 0.25 mg/kg intraperitoneal, and 0.1 mg/kg intravenous routes, followed by blood and urine sampling for LC-MS/MS analysis. Effects on lipid absorption were assessed in another eight JVC rats receiving peanut oil with and without COL, followed by blood pharmacokinetic and plasma biochemistry analysis. The results revealed that COL exhibited moderate extraction ratio and high volume of distribution, with low oral bioavailability (<8%). About 20 % was recovered in the urine after parenteral dosing. Modest but significant reductions in cholesterol absorption was observed after oral doses of 0.5 mg/kg, accompanied by signs of inflammation and increased liver enzymes persisting for a week. The effect of COL on triglycerides formation was not significant. Despite its use as a non-surgical tool in rats to investigate drug absorption via the lymphatic pathway, COL demonstrated increased levels of liver function enzymes, emphasizing the need for caution and dose optimization in its utilization.

On the processes limiting oral drug absorption when amorphous solid dispersions are administered after a high-calorie, high-fat meal: Sporanox® pellets

OBJECTIVES

1) Identify processes limiting the arrival of itraconazole at the intestinal epithelium when Sporanox® amorphous solid dispersion (ASD) pellets are transferred from the stomach through the upper small intestine, after a high-calorie, high-fat meal. 2) Evaluate whether itraconazole concentrations in the colloidal phase of aqueous contents of the upper small intestine are useful for the assessment of dose effects in the fed state and food effects on plasma levels.

METHODS

Itraconazole concentrations, apparent viscosity, and solubilization capacity were measured in aspirates from the upper gastrointestinal lumen collected during a recently performed clinical study in healthy adults. Published itraconazole concentrations in plasma, after a high-calorie high-fat meal and Sporanox® ASD pellets, and in contents of the upper small intestine of healthy adults, after administration of Sporanox® ASD pellets in the fasted state, were used to achieve the second objective.

RESULTS

When Sporanox® ASD pellets (up to 200 mg) are transferred from the stomach through the upper small intestine, after a high-calorie, high-fat meal, itraconazole concentrations in the colloidal phase or the micellar phase of aqueous contents of the upper small intestine are unsaturated, in most cases. During the first 3 h post-dosing after a high-calorie, high-fat meal, the impact of dose (200 mg vs. 100 mg) on itraconazole concentrations in the colloidal phase of aqueous contents of the upper small intestine seems to underestimate the impact of dose on plasma levels. When Sporanox® ASD pellets are administered after a high-calorie, high-fat meal at the 200 mg dose level, itraconazole concentrations in the colloidal phase of aqueous contents of the upper small intestine are, on average, lower than those achieved in fasted state.

CONCLUSIONS

When Sporanox® ASD pellets are transferred from the stomach to the upper small intestine after a high-calorie, high-fat meal, itraconazole's arrival at the intestinal epithelium seems to be limited by its arrival at the colloidal phase of aqueous contents of the upper small intestine. The impact of dose (100 mg vs. 200 mg) on plasma levels after a high-calorie, high-fat meal and during the gastrointestinal transfer of Sporanox® pellets requires consideration of pre-systemic itraconazole metabolism. At the 200 mg dose level, after taking into consideration differences in the volume of the contents of the upper small intestine between the fasted and the fed state during the gastrointestinal transfer of Sporanox® ASD pellets, itraconazole concentrations in the colloidal phase of aqueous contents of the upper small intestine suggest a mild negative food effect on average plasma levels; published clinical data are inconclusive.

Lymphatic Uptake of a Highly Lipophilic Protease Inhibitor Prodrug from a Lipid-Based Formulation is Limited by Instability in the Intestine

Dabigatran etexilate (DABE) is a lipophilic double alkyl ester prodrug of dabigatran (DAB) which is a serine protease inhibitor used clinically as an anticoagulant. Recently, translocation of serine protease enzymes, including trypsin, from the gut into the mesenteric lymph and then blood has been associated with organ failure in acute and critical illnesses (ACIs). Delivery of DABE into mesenteric lymph may thus be an effective strategy to prevent organ failure in ACIs. Most drugs access the mesenteric lymph in low quantities following oral administration, as they are rapidly transported away from the intestine via the blood. Here, we examine the potential to deliver DABE into the mesenteric lymph by promoting association with lymph lipid transport pathways via co-administration with a lipid-based formulation (LBF). A series of self-emulsifying LBFs were designed and tested in vitro for their potential to form stable DABE loaded emulsions and keep DABE solubilised and stable over time in simulated gastrointestinal conditions. The LBFs were found to form fine emulsions with a droplet size of 214 ± 30 nm and DABE was stable in the formulation. The stability of DABE in vitro in simulated intestinal conditions, plasma and lymph samples was also evaluated to ensure stability in collected samples and to evaluate whether the prodrug is likely to release active DAB. Ultimately, a highly uniform and stable self-emulsifying Type III A LBF of DABE was chosen for progression into in vivo studies in male Sprague Dawley rats to confirm the lymphatic uptake and plasma pharmacokinetics. Both in vitro and in vivo in plasma and lymph, DABE was rapidly converted to an intermediate and DAB. The main species present in vivo in both plasma and lymph was DAB and mass transport of DABE and DAB in lymph was minimal (∼0.5 % of dose). Importantly, the concentration of DABE in lymph was substantially (20-176 fold) higher than in plasma, supporting that if the prodrug were stable and did not convert to DAB in the intestine, it would be lymphatically transported. Future studies will therefore focus on optimizing the design of the prodrug and formulation to improve stability during absorption and further promote lymphatic uptake.

Development and in vitro evaluation of an infant friendly self-nanoemulsifying drug delivery system (SNEDDS) loaded with an amphotericin B-monoacyl phosphatidylcholine complex for oral delivery

Until relatively recently, the pediatric population has largely been ignored during the development of new drug products, which has led to a high level of "off-label" use of drugs in this particular population. In this study, an infant friendly self-nanoemulsifying drug delivery system (SNEDDS) was developed for oral delivery of a commonly used "off-label" drug - amphotericin B (AmB). AmB was complexed with monoacyl-phosphatidylcholine (MAPC) by lyophilization, transforming crystalline AmB into its amorphous state in the AmB-MAPC complex (APC). The APC-loaded SNEDDS (APC-SNEDDS) showed excellent self-emulsifying properties; after dispersion of the APC-SNEDDS in purified water, nanoscale emulsion droplets were formed within 1 min with a z-average size of 179 ± 1 nm. In vitro pediatric gastrointestinal (GI) digestion and dissolution results showed that the APC-SNEDDS significantly increased the amount of AmB solubilized in aqueous phase and that the precipitated AmB from the APC-SNEDDS re-dissolved faster, compared with crystalline AmB in SNEDDS (AmB-SNEDDS), the complex without the SNEDDS (APC), the physical mixture of AmB and MAPC (AmB/MAPC PM), and crystalline AmB alone (AmB). Overall, the present in vitro results suggest that integrating the APC into an infant friendly SNEDDS is a promising approach for oral delivery of AmB to young pediatric patients.

Surfactant-Polymer Complexation and Competition on Drug Nanocrystal Surfaces Control Crystallinity

Nanosizing drug crystals has emerged as a successful approach to enabling oral bioavailability, as increasing drug crystal surface area improves dissolution kinetics and effective solubility. Recently, bottom-up methods have been developed to directly assemble nanosized crystals by leveraging polymer and surfactant excipients during crystallization to control crystal size, morphology, and structure. However, while significant research has investigated how polymers and other single additives inhibit or promote crystallization in pharmaceutical systems, there is little work studying the mechanistic interactions of multiple excipients on drug crystal structure and the extent of crystallinity, which can influence formulation performance. This study explores how the structure and crystallinity of a model hydrophobic drug crystal, fenofibrate, change as a result of competitive interfacial chemisorption between common nonionic surfactants (polysorbate 80 and sorbitan monooleate) and a surface-active polymer excipient (methylcellulose). Classical molecular dynamics simulations highlight how key intermolecular interactions, including surfactant-polymer complexation and surfactant screening of the crystal surface, modify the resulting crystal structure. In parallel, experiments generating drug nanocrystals in hydrogel thin films validate that drug crystallinity increases with an increasing weight fraction of surfactant. Simulation results reveal a connection between accelerated dynamics in the bulk crystal and the experimentally measured extent of crystallinity. To our knowledge, these are the first simulations that directly characterize structural changes in a drug crystal as a result of excipient surface composition and relate the experimental extent of crystallinity to structural changes in the molecular crystal. Our approach provides a mechanistic understanding of crystallinity in nanocrystallization, which can expand the range of orally deliverable small molecule therapies.

Liposomes delivery systems of functional substances for precision nutrition

Natural bioactive compounds with antioxidant, antimicrobial, anticancer, and other biological activities are vital for maintaining the body's physiological functions and enhancing immunity. These compounds have great potential as nutritional therapeutic agents, but they can be limited due to their poor flavor, color, unstable nature, and poor water solubility, and degradation by gastrointestinal enzymes. Liposomes, as ideal carriers, can encapsulate both water-soluble and fat-soluble nutrients, enhance the bioavailability of functional substances, promote the biological activity of functional substances, and control the release of nutrients. Despite their potential, liposomes still face obstacles in nutrient delivery. Therefore, the design of liposomes for special needs, optimization of the liposome preparation process, enhancement of liposome encapsulation efficiency, and industrial production are key issues that must be addressed in order to develop food-grade liposomes. Moreover, the research on surface-targeted modification and surface functionalization of liposomes is valuable for expanding the scope of application of liposomes and achieving the release of functional substances from liposomes at the appropriate time and site. The establishment of in vivo and in vitro digestion models of nutrient-loaded liposomes, in-depth study of gastrointestinal digestive behavior after liposome ingestion, targeted nutrient release, and deciphering the nutritional intervention of human diseases and positive health promotion are promising fields with broad development prospects.

Rationalizing Counterion Selection for the Development of Lipophilic Salts: A Case Study with Venetoclax

The use of lipid-based formulations (LBFs) can be hindered by low dose loading due to solubility limitations of candidate drugs in lipid vehicles. Formation of lipophilic salts through pairing these drugs with a lipophilic counterion has been demonstrated as a potential means to enhance dose loading in LBFs. This study investigated the screening of appropriate counterions to form lipophilic salts of the BCS class IV drug venetoclax. The physical properties, lipid solubility, and in vitro performance of the salts were analyzed. This study illustrated the versatility of alkyl sulfates and sulfonates as suitable counterions in lipophilic salt synthesis with up to ∼9-fold higher solubility in medium- and long-chain LBFs when compared to that of the free base form of venetoclax. All salts formulated as LBFs displayed superior in vitro performance when compared to the free base form of the drug due to the higher initial drug loadings in LBFs and increased affinity for colloidal species. Further, in vitro studies confirmed that venetoclax lipophilic salt forms using alkyl chain counterions demonstrated comparable in vitro performance to venetoclax docusate, thus reducing the potential for laxative effects related to docusate administration. High levels of the initial dose loading of venetoclax lipophilic salts were retained in a molecularly dispersed state during dispersion and digestion of the formulation, while also demonstrating increased levels of saturation in biorelevant media. The findings of this study suggest that alkyl chain sulfates and sulfonates can act as a suitable alternative counterion to docusate, facilitating the selection of counterions that can unlock the potential to formulate venetoclax as an LBF.

Encapsulated phenolic compounds: clinical efficacy of a novel delivery method

Encapsulation is a drug or food ingredient loaded-delivery system that entraps active components, protecting them from decomposition/degradation throughout the processing and storage stages and facilitates their delivery to the target tissue/organ, improving their bioactivities. The application of this technology is expanding gradually from pharmaceuticals to the food industry, since dietary bioactive ingredients, including polyphenols, are susceptible to environmental and/or gastrointestinal conditions. Polyphenols are the largest group of plants' secondary metabolites, with a wide range of biological effects. Literature data have indicated their potential in the prevention of several disorders and pathologies, ranging from simpler allergic conditions to more complex metabolic syndrome and cardiovascular and neurodegenerative diseases. Despite the promising health effects in preclinical studies, the clinical use of dietary polyphenols is still very limited due to their low bioaccessibility and/or bioavailability. Encapsulation can be successfully employed in the development of polyphenol-based functional foods, which may improve their bioaccessibility and/or bioavailability. Moreover, encapsulation can also aid in the targeted delivery of polyphenols and may prevent any possible adverse events. For the encapsulation of bioactive ingredients, several techniques are applied such as emulsion phase separation, emulsification/internal gelation, film formation, spray drying, spray-bed-drying, fluid-bed coating, spray-chilling, spray-cooling, and melt injection. The present review aims to throw light on the existing literature highlighting the possibility and clinical benefits of encapsulated polyphenols in health and disease. However, the clinical data is still very scarce and randomized clinical trials are needed before any conclusion is drawn.

Graphical abstract

Lipid-based systems with precipitation inhibitors as formulation approach to improve the drug bioavailability and/or lower its dose: a review

Lipid-based systems, such as self-microemulsifying systems (SMEDDS) are attracting strong attention as a formulation approach to improve the bioavailability of poorly water-soluble drugs. By applying the "spring and parachute" strategy in designing supersaturable SMEDDS, it is possible to maintain the drug in the supersaturated state long enough to allow absorption of the complete dose, thus improving the drug's bio-availability. As such an approach allows the incorporation of larger amounts of the drug in equal or even lower volumes of SMEDDS, it also enables the production of smaller final dosage forms as well as decreased gastrointestinal irritation, being of particular importance when formulating dosage forms for children or the elderly. In this review, the technological approaches used to prolong the drug supersaturation are discussed regarding the type and concentration of polymers used in liquid and solid SMEDDS formulation. The addition of hypromellose derivatives, vinyl polymers, polyethylene glycol, polyoxyethylene, or polymetacrylate copolymers proved to be effective in inhibiting drug precipitation. Regarding the available literature, hypromellose has been the most commonly used polymeric precipitation inhibitor, added in a concentration of 5 % (m/m). However, the inhibiting ability is mainly governed not only by the physicochemical properties of the polymer but also by the API, therefore the choice of optimal precipitation inhibitor is recommended to be evaluated on an individual basis.

Interactions between nanoparticles and lymphatic systems: Mechanisms and applications in drug delivery

The lymphatic system has garnered significant attention in drug delivery research due to the advantages it offers, such as enhancing systemic exposure and enabling lymph node targeting for nanomedicines via the lymphatic delivery route. The journey of drug carriers involves transport from the administration site to the lymphatic vessels, traversing the lymph before entering the bloodstream or targeting specific lymph nodes. However, the anatomical and physiological barriers of the lymphatic system play a pivotal role in influencing the behavior and efficiency of carriers. To expedite research and subsequent clinical translation, this review begins by introducing the composition and classification of the lymphatic system. Subsequently, we explore the routes and mechanisms through which nanoparticles enter lymphatic vessels and lymph nodes. The review further delves into the interactions between nanomedicine and body fluids at the administration site or within lymphatic vessels. Finally, we provide a comprehensive overview of recent advancements in lymphatic delivery systems, addressing the challenges and opportunities inherent in current systems for delivering macromolecules and vaccines.

Recent Advancements in Metallic Au- and Ag-Based Chitosan Nanocomposite Derivatives for Enhanced Anticancer Drug Delivery

The rapid advancements in nanotechnology in the field of nanomedicine have the potential to significantly enhance therapeutic strategies for cancer treatment. There is considerable promise for enhancing the efficacy of cancer therapy through the manufacture of innovative nanocomposite materials. Metallic nanoparticles have been found to enhance the release of anticancer medications that are loaded onto them, resulting in a sustained release, hence reducing the dosage required for drug administration and preventing their buildup in healthy cells. The combination of nanotechnology with biocompatible materials offers new prospects for the development of advanced therapies that exhibit enhanced selectivity, reduced adverse effects, and improved patient outcomes. Chitosan (CS), a polysaccharide possessing distinct physicochemical properties, exhibits favorable attributes for controlled drug delivery due to its biocompatibility and biodegradability. Chitosan nanocomposites exhibit heightened stability, improved biocompatibility, and prolonged release characteristics for anticancer medicines. The incorporation of gold (Au) nanoparticles into the chitosan nanocomposite results in the manifestation of photothermal characteristics, whereas the inclusion of silver (Ag) nanoparticles boosts the antibacterial capabilities of the synthesized nanocomposite. The objective of this review is to investigate the recent progress in the utilization of Ag and Au nanoparticles, or a combination thereof, within a chitosan matrix or its modified derivatives for the purpose of anticancer drug delivery. The research findings for the potential of a chitosan nanocomposite to deliver various anticancer drugs, such as doxorubicin, 5-Fluroacil, curcumin, paclitaxel, and 6-mercaptopurine, were investigated. Moreover, various modifications carried out on the chitosan matrix phase and the nanocomposite surfaces to enhance targeting selectivity, loading efficiency, and pH sensitivity were highlighted. In addition, challenges and perspectives that could motivate further research related to the applications of chitosan nanocomposites in cancer therapy were summarized.

Enabling superior drug loading in lipid-based formulations with lipophilic salts for a brick dust molecule: Exploration of lipophilic counterions and in vitro-in vivo evaluation

Lipid-based formulations (LbFs) are an extensively used approach for oral delivery of poorly soluble drug compounds in the form of lipid suspension and lipid solution. However, the high target dose and inadequate lipid solubility limit the potential of brick dust molecules to be formulated as LbFs. Thus, the complexation of such molecules with a lipophilic counterion can be a plausible approach to improve the solubility in lipid-based solutions via reducing drug crystallinity and polar surface area. The study aimed to enhance drug loading in lipid solution for Nilotinib (Nil) through complexation or salt formation with different lipophilic counterions. We synthesized different lipophilic salts/ complexes via metathesis reactions and confirmed their formation by 1H NMR and FTIR. Docusate-based lipophilic salt showed improved solubility in medium-chain triglycerides (∼7 to 7.5-fold) and long-chain triglycerides (∼30 to 35-fold) based lipids compared to unformulated crystalline Nil. The increased lipid solubility could be attributed to the reduction in drug crystallinity which was further confirmed by the PXRD and DSC. Prototype LbFs were prepared to evaluate drug loading and their physicochemical characteristics. The findings suggested that structural features of counterion including chain length and lipophilicity affect the drug loading in LbF. In addition, physical stability testing of formulations was performed, inferring that aliphatic sulfate-based LbFs were stable with no sign of drug precipitation or salt disproportionation. An in vitro lipolysis-permeation study revealed that the primary driver of absorptive flux is the solubilization of the drug and reduced amount of lipid. Further, the in vivo characterization was conducted to measure the influence of increased drug load on oral bioavailability. Overall, the results revealed enhanced absorption of lipophilic salt-based LbF over unformulated crystalline Nil and conventional LbF (drug load equivalent to equilibrium solubility) which supports the idea that lipophilic salt-based LbF enhances drug loading, and supersaturation-mediated drug solubilization, unlocking the full potential of LbF.

Quantifying the Lymphatic Transport of Model Therapeutics from the Brain in Rats

In recent years, the drainage of fluids, immune cells, antigens, fluorescent tracers, and other solutes from the brain has been demonstrated to occur along lymphatic outflow pathways to the deep cervical lymph nodes in the neck. To the best of our knowledge, no studies have evaluated the lymphatic transport of therapeutics from the brain. The objective of this study was to determine the lymphatic transport of model therapeutics of different molecular weights and lipophilicity from the brain using cervical lymph cannulation and ligation models in rats. To do this, anesthetized Sprague-Dawley rats were cannulated at the carotid artery and cannulated, ligated, or left intact at the cervical lymph duct. Rats were administered 14C-ibuprofen (206.29 g/mol, logP 3.84), 3H-halofantrine HCl (536.89 g/mol, logP 8.06), or 3H-albumin (∼65,000 g/mol) via direct injection into the brain striatum at a rate of 0.5 μL/min over 16 min. Plasma or cervical lymph samples were collected for up to 6-8 h following dosing, and brain and lymph nodes were collected at 6 or 8 h. Samples were subsequently analyzed for radioactivity levels via scintillation counting. For 14C-ibuprofen, plasma concentrations over time (plasma AUC0-6h) were >2 fold higher in lymph-ligated rats than in lymph-intact rats, suggesting that ibuprofen is cleared from the brain primarily via nonlymphatic routes (e.g., across the blood-brain barrier) but that this clearance is influenced by changes in lymphatic flow. For 3H-halofantrine, >73% of the dose was retained at the brain dosing site in lymph-intact and lymph-ligated groups, and plasma AUC0-8h values were low in both groups (<0.3% dose.h/mL), consistent with the high retention in the brain. It was therefore not possible to determine whether halofantrine undergoes lymphatic transport from the brain within the duration of the study. For 3H-albumin, plasma AUC0-8h values were not significantly different between lymph-intact, lymph-ligated, and lymph-cannulated rats. However, >4% of the dose was recovered in cervical lymph over 8 h. Lymph/plasma concentration ratios of 3H-albumin were also very high (up to 53:1). Together, these results indicate that 3H-albumin is transported from the brain not only via lymphatic routes but also via the blood. Similar to other tissues, the lymphatics may thus play a significant role in the transport of macromolecules, including therapeutic proteins, from the brain but are unlikely to be a major transport pathway from the brain for small molecule drugs that are not lipophilic. Our rat cervical lymph cannulation model can be used to quantify the lymphatic drainage of different molecules and factors from the brain.

Development and characterization of solid lipid-based formulations (sLBFs) of ritonavir utilizing a lipolysis and permeation assay

As a high number of active pharmaceutical ingredients (APIs) under development belong to BCS classes II and IV, the need for improving bioavailability is critical. A powerful approach is the use of lipid-based formulations (LBFs) that usually consist of a combination of liquid lipids, cosolvents, and surfactants. In this study, ritonavir loaded solid LBFs (sLBFs) were prepared using solid lipid excipients to investigate whether sLBFs are also capable of improving solubility and permeability. Additionally, the influence of polymeric precipitation inhibitors (PVP-VA and HPMC-AS) on lipolysis triggered supersaturation and precipitation was investigated. One step intestinal digestion and bicompartmental permeation studies using an artificial lecithin-in-dodecane (LiDo) membrane were performed for each formulation. All formulations presented significantly higher solubility (5 to >20-fold higher) during lipolysis and permeation studies compared to pure ritonavir. In the combined lipolysis-permeation studies, the formulated ritonavir concentration increased 15-fold in the donor compartment and the flux increased up to 71 % as compared to non-formulated ritonavir. The formulation with the highest surfactant concentration showed significantly higher ritonavir solubility compared to the formulation with the highest amount of lipids. However, the precipitation rates were comparable. The addition of precipitation inhibitors did not influence the lipolytic process and showed no significant benefit over the initial formulations with regards to precipitation. While all tested sLBFs increased the permeation rate, no statistically significant difference was noted between the formulations regardless of composition. To conclude, the different release profiles of the formulations were not correlated to the resulting flux through a permeation membrane, further supporting the importance of making use of combined lipolysis-permeation assays when exploring LBFs.

Vitamin D loaded into lipid nanoparticles shows insulinotropic effect in INS-1E cells

Increasing evidence suggests a beneficial role of vitamin D (VitD) supplementation in addressing the widespread VitD deficiency, but currently used VitD3 formulations present low bioavailability and toxicity constrains. Hence, poly(L-lactide-co-glycolide) (PLGA) nanoparticles (NPs), solid-lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) were investigated to circumvent these issues. PLGA NPs prepared by emulsification or nanoprecipitation presented 74 or 200 nm, and association efficiency (AE) of 68 % and 17 %, respectively, and a rapid burst release of VitD3. Both SLN and NLCs presented higher polydispersity and larger NPs size, around 500 nm, which could be reduced to around 200 nm by use of hot high-pressure homogenization in the case of NLCs. VitD3 was efficiently loaded in both SLNs and NLCs with an AE of 82 and 99 %, respectively. While SLNs showed burst release, NLCs allowed a sustained release of VitD3 for nearly one month. Furthermore, NLCs showed high stability with maintenance of VitD3 loading for up to one month at 4 °C and no cytotoxic effects on INS-1E cells up to 72 h. A trending increase (around 30 %) on glucose-dependent insulin secretion was observed by INS-1E cells pre-treated with VitD3. This effect was consistently observed in the free form and after loading on NLCs. Overall, this work contributed to further elucidation on a suitable delivery system for VitD3 and on the effects of this metabolite on β cell function.

Pickering emulsion emulsified using novel cellulose nanofibers significantly lowers the lipid release rate and cellular absorption

A Pickering emulsion is an emulsion system stabilized by solid particles and represents a promising candidate for emulsifying lipids. Cellulose nanofibers (CNFs) have excellent ability to control the lipid release rate. This study aims to find the optimal formulation for a nanocellulose-stabilized Pickering emulsion that is the most effective in reducing the lipid release rate. The Pickering emulsion was prepared by homogenizing pretreated nanocellulose with medium-chain triglycerides using high-speed and ultrasonic homogenizers. The results show that the Pickering emulsion with 0.709% nanocellulose and 30.6% medium-chain fatty acid content yielded an average particle size of approximately 2.5 μm, which is the most stable and effective in reducing the amount of the lipids released. The nanocellulose Pickering emulsion formulation developed in this study forms a significant foundation for future research and applications regarding the use of nanotechnology and Pickering emulsions to maintain the balance between one's health and the desirable flavor of fat.

State-of-the-art drug delivery system to target the lymphatics

PRIMARY OBJECTIVE

The primary objective of the review is to assess the potential of lymphatic-targeted drug delivery systems, with a particular emphasis on their role in tumour therapy and vaccination efficacy.

REASON FOR LYMPHATIC TARGETING

The lymphatic system's crucial functions in maintaining bodily equilibrium, regulating metabolism, and orchestrating immune responses make it an ideal target for drug delivery. Lymph nodes, being primary sites for tumour metastasis, underscore the importance of targeting the lymphatic system for effective treatment.

OUTCOME

Nanotechnologies and innovative biomaterials have facilitated the development of lymphatic-targeted drug carriers, leveraging endogenous macromolecules to enhance drug delivery efficiency. Various systems such as liposomes, micelles, inorganic nanomaterials, hydrogels, and nano-capsules demonstrate significant potential for delivering drugs to the lymphatic system.

CONCLUSION

Understanding the physiological functions of the lymphatic system and its involvement in diseases underscores the promise of targeted drug delivery in improving treatment outcomes. The strategic targeting of the lymphatic system presents opportunities to enhance patient prognosis and advance therapeutic interventions across various medical contexts, indicating the importance of ongoing research and development in this area.

Fabrication and characterization of chitosan-pectin emulsion-filled hydrogel prepared by cold-set gelation to improve bioaccessibility of lipophilic bioactive compounds

Chitosan-pectin emulsion-filled hydrogel (EFH) was developed to enhance the bioaccessibility of lipophilic bioactive compounds through intestinal delivery. The EFH, incorporating a sodium caseinate-stabilized emulsion, was prepared using cold-set gelation under acidic conditions without crosslinking agents. Increasing the pectin concentration (0.75-1.50%, w/v) improved the mechanical strength and compactness of the EFH. The pH-responsive EFH retained the emulsion at pH 2.0 and released it at pH 7.4. In vitro digestion demonstrated that the EFH remained intact during oral and gastric stages, while the emulsion alone became destabilized. During intestinal digestion, the release of free fatty acids from the EFH decreased from 58.67% to 43.76% as the pectin concentration increased from 0.75% to 1.50%. EFH with 0.75% and 1.00% pectin significantly improved curcumin bioaccessibility compared to the emulsion alone. These findings demonstrate the potential of chitosan-pectin EFH as a novel carrier system for enhancing the bioaccessibility of lipophilic bioactive compounds.

Maximizing Aqueous Drug Encapsulation: Small Nanoparticles Formation Enabled by Glycopolymers Combining Glucose and Tyrosine

Highly potent heterocyclic drugs are frequently poorly water soluble, leading to limited or abandoned further drug development. Nanoparticle technology offers a powerful delivery approach by enhancing the solubility and bioavailability of hydrophobic therapeutics. However, the common usage of organic solvents causes unwanted toxicity and process complexity, therefore limiting the scale-up of nanomedicine technology for clinical translation. Here, we show that an organic-solvent-free methodology for hydrophobic drug encapsulation can be obtained using polymers based on glucose and tyrosine. An aqueous solution based on a tyrosine-containing glycopolymer is able to dissolve solid dasatinib directly without adding an organic solvent, resulting in the formation of very small nanoparticles of around 10 nm loaded with up to 16 wt % of drug. This polymer is observed to function as both a drug solubilizer and a nanocarrier at the same time, offering a simple route for the delivery of insoluble drugs.

Lipid-Based Self-Microemulsion of Niclosamide Achieved Enhanced Oral Delivery and Anti-Tumor Efficacy in Orthotopic Patient-Derived Xenograft of Hepatocellular Carcinoma in Mice

Introduction

We previously identified niclosamide as a promising repurposed drug candidate for hepatocellular carcinoma (HCC) treatment. However, it is poorly water soluble, limiting its tissue bioavailability and clinical application. To overcome these challenges, we developed an orally bioavailable self-microemulsifying drug delivery system encapsulating niclosamide (Nic-SMEDDS).

Methods

Nic-SMEDDS was synthesized and characterized for its physicochemical properties, in vivo pharmacokinetics and absorption mechanisms, and in vivo therapeutic efficacy in an orthotopic patient-derived xenograft (PDX)-HCC mouse model. Niclosamide ethanolamine salt (NEN), with superior water solubility, was used as a positive control.

Results

Nic-SMEDDS (5.6% drug load) displayed favorable physicochemical properties and drug release profiles in vitro. In vivo, Nic-SMEDDS displayed prolonged retention time and plasma release profile compared to niclosamide or NEN. Oral administration of Nic-SMEDDS to non-tumor bearing mice improved niclosamide bioavailability and Cmax by 4.1- and 1.8-fold, respectively, compared to oral niclosamide. Cycloheximide pre-treatment blocked niclosamide absorption from orally administered Nic-SMEDDS, suggesting that its absorption was facilitated through the chylomicron pathway. Nic-SMEDDS (100 mg/kg, bid) showed greater anti-tumor efficacy compared to NEN (200 mg/kg, qd); this correlated with higher levels (p < 0.01) of niclosamide, increased caspase-3, and decreased Ki-67 in the harvested PDX tissues when Nic-SMEDDS was given. Biochemical analysis at the treatment end-point indicated that Nic-SMEDDS elevated lipid levels in treated mice.

Conclusion

We successfully developed an orally bioavailable formulation of niclosamide, which significantly enhanced oral bioavailability and anti-tumor efficacy in an HCC PDX mouse model. Our data support its clinical translation for the treatment of solid tumors.

A comprehensive review on lipid nanocarrier systems for cancer treatment: fabrication, future prospects and clinical trials

Over the last few decades, cancer has been considered a clinical challenge, being among the leading causes of mortality all over the world. Although many treatment approaches have been developed for cancer, chemotherapy is still the most utilized in the clinical setting. However, the available chemotherapeutics-based treatments have several caveats including their lack of specificity, adverse effects as well as cancer relapse and metastasis which mainly explains the low survival rate of patients. Lipid nanoparticles (LNPs) have been utilized as promising nanocarrier systems for chemotherapeutics to overcome the challenges of the currently applied therapeutic strategies for cancer treatment. Loading chemotherapeutic agent(s) into LNPs improves drug delivery at different aspects including specific targeting of tumours, and enhancing the bioavailability of drugs at the tumour site through selective release of their payload, thus reducing their undesired side effects on healthy cells. This review article delineates an overview of the clinical challenges in many cancer treatments as well as depicts the role of LNPs in achieving optimal therapeutic outcomes. Moreover, the review contains a comprehensive description of the many LNPs categories used as nanocarriers in cancer treatment to date, as well as the potential of LNPs for future applications in other areas of medicine and research.

Ivacaftor pharmacokinetics and lymphatic transport after enteral administration in rats

Background: Ivacaftor is a modern drug used in the treatment of cystic fibrosis. It is highly lipophilic and exhibits a strong positive food effect. These characteristics can be potentially connected to a pronounced lymphatic transport after oral administration. Methods: A series of studies was conducted to describe the basic pharmacokinetic parameters of ivacaftor in jugular vein cannulated rats when dosed in two distinct formulations: an aqueous suspension and an oil solution. Additionally, an anesthetized mesenteric lymph duct cannulated rat model was studied to precisely assess the extent of lymphatic transport. Results: Mean ± SD ivacaftor oral bioavailability was 18.4 ± 3.2% and 16.2 ± 7.8%, respectively, when administered as an aqueous suspension and an oil solution. The relative contribution of the lymphatic transport to the overall bioavailability was 5.91 ± 1.61% and 4.35 ± 1.84%, respectively. Conclusion: Lymphatic transport plays only a minor role in the process of ivacaftor intestinal absorption, and other factors are, therefore, responsible for its pronounced positive food effect.

Application of Oil-in-Water Cannabidiol Emulsion for the Treatment of Rheumatoid Arthritis

Introduction: Rheumatoid arthritis (RA) is a chronic autoimmune disease with unknown cause. It mainly affects joints and, without proper treatment, negatively impacts their movement, causes painful deformities, and reduces the patients' quality of life. Current treatment options consist of various types of disease-modifying antirheumatic drugs (DMARDs), however 20-30% of patients are partially resistant to them. Therefore, development of new drugs is necessary. Possible option are compounds exhibiting their action via endocannabinoid system, which plays an important role in pain and inflammation modulation. One such compound - cannabidiol (CBD) has already been shown to attenuate synovitis in animal model of RA in in vivo studies. However, it has low bioavailability due to its low water solubility and lipophilicity. This issue can be addressed by preparation of a lipid containing formulation targeting lymphatic system, another route of absorption in the body. Materials and Methods: CBD-containing emulsion was prepared by high-shear homogenization and its droplet size distribution was analysed by optical microscopy. The relative oral bioavailability compared to oil solution as well as total availability of CBD were assessed in a cross-over study in rats and absorption of CBD via lymphatic system was observed. The effect of CBD on the animal model of RA was determined. Results: Compared to oil solution, the emulsion exhibited higher absolute oral bioavailability. Significant lymphatic transport of CBD was observed in all formulations and the concentrations in lymph were calculated. The therapeutic effect of CBD on RA was confirmed as an improvement in clinical symptoms as well as morphological signs of disease activity were observed during the study. Conclusion: In this work, we prepared a simple stable emulsion formulation, determined the pharmacokinetic parameters of CBD and calculated its absolute bioavailability in rats. Moreover, we successfully tested the pharmaceutical application of such a formulation and demonstrated the positive effect of CBD in an animal model of RA.

Early evaluation of opportunities in oral delivery of PROTACs to overcome their molecular challenges

PROteolysis TArgeting Chimeras (PROTACs) offer new opportunities in modern medicine by targeting proteins that are intractable to classic inhibitors. Heterobifunctional in nature, PROTACs are small molecules that offer a unique mechanism of protein degradation by hijacking the ubiquitin-mediated protein degradation pathway, known as the ubiquitin-proteasome system. Herein, we present an analysis on the structural characteristics of this novel chemical modality. Furthermore, we review and discuss the formulation opportunities to overcome the oral delivery challenges of PROTACs in drug discovery.

The effect of polymeric binder type and concentration on flow and dissolution properties of SMEDDS loaded mesoporous silica-based granules

Self-microemulsifying drug delivery systems (SMEDDS) are lipid-based formulations, designed to improve the solubility of poorly-water soluble drugs. Mesoporous silica is frequently used for SMEDDS solidification by various techniques. One of them is wet granulation, which enables achieving both high SMEDDS load and good flow properties. This study investigated the effect of six polymeric binders' addition to granulation dispersion (GD) (povidone K30, povidone K90, copovidone, Pharmacoat® 603, Pharmacoat® 615 and Methocel™ K100 Premium LV) on characteristics of produced SMEDDS granules, prepared by wet granulation. By incorporation of polymer in GD, it was possible to produce mesoporous silica-based free-flowing granules, with preserved self-microemulsifying properties, responsible for improved in vitro release of carvedilol. The incorporation of higher molecular weight binders resulted in slower in vitro release, while high binder concentration was related to faster drug release. The highest release rate was achieved with povidone K30 at 7.45 % binder concentration, as corresponding granules exhibited complete drug release already in 5 min. Granulation method (manual vs. high-shear) influenced the release rate of carvedilol as it was released slower from SMEDDS granules prepared using the granulator. Finally, SMEDDS tablet formulation was optimized to achieve maximum granule content and adequate tablet hardness. Increased granule content found to negatively influence tablet hardness, as maximum granule content of 25 % was needed to obtain appropriate hardness. Such tablets exhibited short disintegration time, so this final prototype can be considered as orodispersible tablet.

Charge-Reversible Nanoparticles: Advanced Delivery Systems for Therapy and Diagnosis

The past two decades have witnessed a rapid progress in the development of surface charge-reversible nanoparticles (NPs) for drug delivery and diagnosis. These NPs are able to elegantly address the polycation dilemma. Converting their surface charge from negative/neutral to positive at the target site, they can substantially improve delivery of drugs and diagnostic agents. By specific stimuli like a shift in pH and redox potential, enzymes, or exogenous stimuli such as light or heat, charge reversal of NP surface can be achieved at the target site. The activated positive surface charge enhances the adhesion of NPs to target cells and facilitates cellular uptake, endosomal escape, and mitochondrial targeting. Because of these properties, the efficacy of incorporated drugs as well as the sensitivity of diagnostic agents can be essentially enhanced. Furthermore, charge-reversible NPs are shown to overcome the biofilm formed by pathogenic bacteria and to shuttle antibiotics directly to the cell membrane of these microorganisms. In this review, the up-to-date design of charge-reversible NPs and their emerging applications in drug delivery and diagnosis are highlighted.

Oral nanomedicine biointeractions in the gastrointestinal tract in health and disease

Oral administration is the preferred route of administration based on the convenience for and compliance of the patient. Oral nanomedicines have been developed to overcome the limitations of free drugs and overcome gastrointestinal (GI) barriers, which are heterogeneous across healthy and diseased populations. This review aims to provide a comprehensive overview and comparison of the oral nanomedicine biointeractions in the gastrointestinal tract (GIT) in health and disease (GI and extra-GI diseases) and highlight emerging strategies that exploit these differences for oral nanomedicine-based treatment. We introduce the key GI barriers related to oral delivery and summarize their pathological changes in various diseases. We discuss nanomedicine biointeractions in the GIT in health by describing the general biointeractions based on the type of oral nanomedicine and advanced biointeractions facilitated by advanced strategies applied in this field. We then discuss nanomedicine biointeractions in different diseases and explore how pathological characteristics have been harnessed to advance the development of oral nanomedicine.

Application of small angle X-ray scattering in exploring the effect of edible oils with different unsaturation FAs on bioaccessibility of stigmasterol oleate

BACKGROUND

Phytosterol can improve its lipid solubility, lipophilic/hydrophilic balance and bioaccessibility by esterification with fatty acids, which increases its practical application range in the food industry. In the present study, small angle X-ray scattering combined with the pH-stat in vitro digestion model was applied to continuously monitor the molecular structure evolution of mixed micelles during digestion and investigate the effect of three edible oils (olive oil with 72.41 ± 0.57% oleic, sunflower seed oil with 63.45 ± 0.78% linoleic, refined linseed oil with 51.74 ± 0.34% linolenic) on bioaccessibility of stigmasterol oleate in vitro.

RESULTS

The release degree and rate of fatty acids in the three edible oil systems (kOO+ST-OA  = 0.0501, kSO+ ST-OA  = 0.0357, kLO+ST-OA  = 0.0323) was compared. The three different edible oils had similar impact on the formation of dietary mixed micelles during the simulatedin vitro digestion of stigmasterol oleate, although there were significant differences in molecular morphology and composition of mixed micelles. The results showed that the vesicles formed by linoleic oil (SO system) or linolenic oil (LO system) were easy to dissociate. The largest average number and diameter of vesicles (5.55 × 1016  cm-3 and 2230.75 Å), the most stable vesicle structure and the fastest fatty acid release rate were observed in the OO system.

CONCLUSION

Compared to linoleic (SO system) or linolenic (LO system), the oleic (OO system) could facilitate the transformation of micelles to vesicles and maintain the stability of its membrane, significantly promotin the dissolution of stigmasterol and improving bioaccessibility. © 2023 Society of Chemical Industry.

Nanocarriers transport across the gastrointestinal barriers: The contribution to oral bioavailability via blood circulation and lymphatic pathway

Oral administration is the preferred route of drug delivery in clinical practice due to its noninvasiveness, safety, convenience, and high patient compliance. The gastrointestinal tract (GIT) plays a crucial role in facilitating the targeted delivery of oral drugs. However, the GIT presents multiple barriers that impede drug absorption, including the gastric barrier in the stomach and the mucus and epithelial barriers in the intestine. In recent decades, nanotechnology has emerged as a promising approach for overcoming these challenges by utilizing nanocarrier-based drug delivery systems such as liposomes, micelles, polymeric nanoparticles, solid lipid nanoparticles, and inorganic nanoparticles. Encapsulating drugs within nanocarriers not only protects them from degradation but also enhances their transport and absorption across the GIT, ultimately improving oral bioavailability. The aim of this review is to elucidate the mechanisms underlying nanocarrier-mediated transportation across the GIT into systemic circulation via both the blood circulation and lymphatic pathway.

Bilosomes and Biloparticles for the Delivery of Lipophilic Drugs: A Preliminary Study

In this study, bile acid-based vesicles and nanoparticles (i.e., bilosomes and biloparticles) are studied to improve the water solubility of lipophilic drugs. Ursodeoxycholic acid, sodium cholate, sodium taurocholate and budesonide were used as bile acids and model drugs, respectively. Bilosomes and biloparticles were prepared following standard protocols with minor changes, after a preformulation study. The obtained systems showed good encapsulation efficiency and dimensional stability. Particularly, for biloparticles, the increase in encapsulation efficiency followed the order ursodeoxycholic acid < sodium cholate < sodium taurocholate. The in vitro release of budesonide from both bilosytems was performed by means of dialysis using either a nylon membrane or a portion of Wistar rat small intestine and two receiving solutions (i.e., simulated gastric and intestinal fluids). Both in gastric and intestinal fluid, budesonide was released from bilosystems more slowly than the reference solution, while biloparticles showed a significant improvement in the passage of budesonide into aqueous solution. Immunofluorescence experiments indicated that ursodeoxycholic acid bilosomes containing budesonide are effective in reducing the inflammatory response induced by glucose oxidase stimuli and counteract ox-inflammatory damage within intestinal cells.

Synergistic stabilization of emulsion gel by nanoparticles and surfactant enables 3D printing of lipid-rich solid oral dosage forms

Pharmaceutical formulation of oral dosage forms is continuously challenged by the low solubility of new drug candidates. Pickering emulsions, emulsions stabilized with solid particles, are a promising alternative to surfactants for developing long-term stable emulsions that can be tailored for controlled release of lipophilic drugs. In this work, a non-emulsifying lipid-based formulation (LBF) loaded with fenofibrate was formulated into an oil-in-water (O/W) emulsion synergistically stabilized by stearic acid and silica (SiO2) nanoparticles. The emulsion had a droplet size of 341 nm with SiO2 particles partially covering the oil-water interface. In vitro lipid digestion was faster for the emulsion compared to the corresponding LBF due to the larger total surface area available for digestion. Cellulose biopolymers were added to the emulsion to produce a gel for semi-solid extrusion (SSE) 3D printing into tablets. The emulsion gel showed suitable rheological attributes for SSE, with a trend of higher viscosity, yield stress, and storage modulus (G'), compared to a conventional self-emulsifying lipid-based emulsion gel. The developed emulsion gel allows for a non-emulsifying LBF to be transformed into solid dosage forms for rapid lipid digestion and drug release of a poorly water-soluble drug in the small intestine.