Bile Acids and Their Derivatives as Potential Modifiers of Drug Release and Pharmacokinetic Profiles

Transethosome: An ultra-deformable ethanolic vesicle for enhanced transdermal drug delivery

Drug delivery through the skin improves solubility, bioavailability, and unwanted systemic side effects of the drug. The selection of a suitable carrier is a challenging process. The conventional lipid vesicles have some limitations. They deliver the drug in the stratum corneum and have poor colloidal stability. Here comes the need for ultra-deformable lipid vesicles to provide the drug beyond the stratum corneum. Transethosomes are novel ultra-deformable vesicles that can deliver drugs into deeper tissues. The composition of transethosomes includes phospholipid, ethanol and surfactants. Each ingredient has a pivotal role in the properties of the carrier. This review covers the design, preparation method, characterisation, and characteristics of the novel vesicle. Also, we cover the impact of surfactants on vesicular properties and the skin permeation behaviour of novel vesicles.

Molecular Hybridization as a Strategy for Developing Artemisinin-Derived Anticancer Candidates

Artemisinin is a natural compound extracted from Artemisia species belonging to the Asteraceae family. Currently, artemisinin and its derivatives are considered among the most significant small-molecule antimalarial drugs. Artemisinin and its derivatives have also been shown to possess selective anticancer properties, however, there are several limitations and gaps in knowledge that retard their repurposing as effective anticancer agents. Hybridization resulting from a covalent combination of artemisinin with one or more active pharmacophores has emerged as a promising approach to overcome several issues. The variety of hybridization partners allows improvement in artemisinin activity by tuning the ability of conjugated artemisinin to interact with various molecule targets involved in multiple biological pathways. This review highlights the current scenario of artemisinin-derived hybrids with potential anticancer activity. The synthetic approaches to achieve the corresponding hybrids and the structure-activity relationships are discussed to facilitate further rational design of more effective candidates.

A Combined In-Vitro and GastroPlus® Modeling to Study the Effect of Intestinal Precipitation on Cinnarizine Plasma Profile in a Fasted State

Poorly water-soluble weak base molecules such as cinnarizine often exhibit pH-dependent solubility within the gastrointestinal tract. This means that their solubility can be influenced by the pH of the surrounding environment, and this can affect their oral absorption. The differential pH solubility between the fasted-state stomach and intestine is an important consideration when studying the oral absorption of cinnarizine. Cinnarizine has moderate permeability and is known to exhibit supersaturation and precipitation in fasted-state simulated intestinal fluid (FaSSIF), which can significantly impact its oral absorption. The present work is aimed at studying the precipitation behavior of cinnarizine in FaSSIF using biorelevant in vitro tools and GastroPlus^® modeling, to identify the factors contributing to the observed variability in clinical plasma profiles. The study found that cinnarizine demonstrated variable precipitation rates under different bile salt concentrations, which could impact the concentration of the drug available for absorption. The results also showed that a precipitation-integrated modeling approach accurately predicted the mean plasma profiles from the clinical studies. The study concluded that intestinal precipitation may be one of the factors contributing to the observed variability in C_max but not the AUC of cinnarizine. The study further suggests that the integration of experimental precipitation results representing a wider range of FaSSIF conditions would increase the probability of predicting some of the observed variability in clinical results. This is important for biopharmaceutics scientists, as it can help them evaluate the risk of in vivo precipitation impacting drug and/or drug product performance.

Gut Microbial Metabolite Butyrate and Its Therapeutic Role in Inflammatory Bowel Disease: A Literature Review

Background and objective: Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a chronic inflammatory disorder characterized by aberrant immune responses and compromised barrier function in the gastrointestinal tract. IBD is associated with altered gut microbiota and their metabolites in the colon. Butyrate, a gut microbial metabolite, plays a crucial role in regulating immune function, epithelial barrier function, and intestinal homeostasis. In this review, we aim to present an overview of butyrate synthesis and metabolism and the mechanism of action of butyrate in maintaining intestinal homeostasis and to discuss the therapeutic implications of butyrate in IBD. Methods: We searched the literature up to March 2023 through PubMed, Web of Science, and other sources using search terms such as butyrate, inflammation, IBD, Crohn's disease, and ulcerative colitis. Clinical studies in patients and preclinical studies in rodent models of IBD were included in the summary of the therapeutic implications of butyrate. Results: Research in the last two decades has shown the beneficial effects of butyrate on gut immune function and epithelial barrier function. Most of the preclinical and clinical studies have shown the positive effect of butyrate oral supplements in reducing inflammation and maintaining remission in colitis animal models and IBD patients. However, butyrate enema showed mixed effects. Butyrogenic diets, including germinated barley foodstuff and oat bran, are found to increase fecal butyrate concentrations and reduce the disease activity index in both animal models and IBD patients. Conclusions: The current literature suggests that butyrate is a potential add-on therapy to reduce inflammation and maintain IBD remission. Further clinical studies are needed to determine if butyrate administration alone is an effective therapeutic treatment for IBD.

Pharmaceutical characterization of probucol bile acid-lithocholic acid nanoparticles to prevent chronic hearing related and similar cellular oxidative stress pathologies

Background: Sensorineural hearing loss has been associated with oxidative stress. However, an antioxidant that passes effectively through the ear remains elusive. Method: Probucol (PB)-based nanoparticles were formed using a spray-drying encapsulation technique, characterized and tested in vitro. Results: Uniform, spherical nanoparticles were produced. The addition of lithocholic acid to PB formulations did not affect drug content or production yield, but it did modify capsule size, surface tension, electrokinetic stability and drug release. Cell viability, bioenergetics and inflammatory profiles were improved when auditory cells were exposed to PB-based nanoparticles, which showed antioxidant properties (p < 0.05). Conclusion: PB-based nanoparticles can potentially protect the auditory cell line from oxidative stress and could be used in future in vivo studies as a potential new therapeutic agent for sensorineural hearing loss.

Approaching strategy to increase the oral bioavailability of berberine, a quaternary ammonium isoquinoline alkaloid: Part 2. Development of oral dosage formulations

INTRODUCTION

Berberine (BBR) possesses a wide variety of pharmacological activities. However, the oral bioavailability of BBR is low due to extensive intestinal first-pass metabolism by cytochrome P450s (CYPs), insufficient absorption due to low solubility and P-glycoprotein (P-gp)-mediated efflux transport, and hepatic first-pass metabolism in rats.

AREAS COVERED

Various dosage formulations were developed to increase the oral bioavailability of BBR by overcoming the reducing factors. This article provides the developing strategy of oral dosage formulations of BBR based on the physicochemical (low solubility, formation of salts/ion-pair complex) and pharmacokinetic properties (substrate of P-gp/CYPs, extensive intestinal first-pass metabolism). Literature was searched by using PubMed.

EXPERT OPINION

Here, formulations increasing the dissolution rates/solubility; formulations containing a P-gp inhibitor; formulations containing solubilizer exhibiting P-gp and/or CYPs inhibitors; formulations containing absorption enhancers; gastro/duodenal retentive formulations; lipid-based formulations; formulations targeting lymphatic transport; and physicochemical modifications increasing lipophilicity were reviewed. Among these formulations, formulations that can reduce intestinal first-pass metabolisms such as formulations containing CYPs inhibitor(s) and formulations containing absorption enhancer(s) significantly increased the oral bioavailability of BBR. Further studies on other dosing routes that can avoid first-pass metabolism such as the rectal route would also be important to increase the bioavailability of BBR.

Monoolein-based nanodispersions for cutaneous co-delivery of methylene blue and metformin: Thermal and structural characterization and effects on the cutaneous barrier, skin penetration and cytotoxicity

This study evaluated the potential of monoolein (MO)-based nanodispersions to promote the cutaneous co-delivery of metformin (MET) and methylene blue (MB) for the treatment of non-melanoma skin cancer. MO-based nanodispersions were obtained using Kolliphor® P407 (KP) and/or sodium cholate (CH), and characterized concerning the structure, thermal stability, ability to disrupt the skin barrier, cutaneous permeation and retention of MB and MET. Additionally, the cytotoxic effect of MO nanodispersions-mediated combination therapy using MET and MB in A431 cells was evaluated. The nanodispersions exhibited nanometric size (<200 nm) and thermal and physical stability. Small angle X-ray scattering studies revealed multiple structures depending on composition. They were able to interact with stratum corneum lipid structure, increasing its fluidity. The effect of MO-nanodispersions on topical/transdermal delivery of MB and MET was composition-dependent. Nanodispersions with low MO content (5 %) and stabilized with KP and CH (0.05-0.10 %) were the most promising, enhancing the cutaneous delivery of MB and MET by 1.9 to 2.2-fold and 1.4 to 1.7-fold, respectively, compared to control. Cytotoxic studies revealed that the most promising MO nanodispersion-mediated combination therapy using MET and MB (1:1) reduced the IC₅₀ by 24-fold, compared to MB solution, and a further reduction (1.5-fold) was observed by MB photoactivation.

Bioaccumulation and biotransformation of simvastatin in probiotic bacteria: A step towards better understanding of drug-bile acids-microbiome interactions

Introduction: Although pharmacogenetics and pharmacogenomics have been at the forefront of research aimed at finding novel personalized therapies, the focus of research has recently extended to the potential of intestinal microbiota to affect drug efficacy. Complex interplay of gut microbiota with bile acids may have significant repercussions on drug pharmacokinetics. However, far too little attention has been paid to the potential implication of gut microbiota and bile acids in simvastatin response which is characterized by large interindividual variations. The Aim: In order to gain more insight into the underlying mechanism and its contribution in assessing the clinical outcome, the aim of our study was to examine simvastatin bioaccumulation and biotransformation in probiotic bacteria and the effect of bile acids on simvastatin bioaccumulation in in vitro conditions. Materials and methods: Samples with simvastatin, probiotic bacteria and three different bile acids were incubated at anaerobic conditions at 37°C for 24 h. Extracellular and intracellular medium samples were collected and prepared for the LC-MS analysis at predetermined time points (0 min, 15 min, 1 h, 2 h, 4 h, 6 h, 24 h). The concentrations of simvastatin were analyzed by LC-MS/MS. Potential biotransformation pathways were analyzed using a bioinformatics approach in correlation with experimental assay. Results: During the incubation, simvastatin was transported into bacteria cells leading to a drug bioaccumulation over the time, which was augmented upon addition of bile acids after 24 h. A decrease of total drug level during the incubation indicates that the drug is partly biotransformed by bacterial enzymes. According to the results of bioinformatics analysis, the lactone ring is the most susceptible to metabolic changes and the most likely reactions include ester hydrolysis followed by hydroxylation. Conclusion: Results of our study reveal that bioaccumulation and biotransformation of simvastatin by intestinal bacteria might be the underlying mechanisms of altered simvastatin bioavailability and therapeutic effect. Since this study is based only on selected bacterial strains in vitro, further more in-depth research is needed in order to elicit completely the contribution of complex drug-microbiota-bile acids interactions to overall clinical response of simvastatin which could ultimately lead to novel approaches for the personalized lipid-lowering therapy.

Nose-to-brain delivery of galantamine loaded nanospray dried polyacrylic acid/taurodeoxycholate mixed matrix as a protective therapy in lipopolysaccharide-induced Alzheimer's in mice model

One of the promising drug delivery approaches is performed by nanosizing the administered drug product using the nanospray drying technique. In this study, a combination of several formulation factors was integrated and exploited to augment the bioavailability of galantamine hydrobromide (GAL) via the intranasal route. Nanosized polymeric particles were fabricated using the mucoadhesive polymer, polyacrylic acid (PAA), and the permeability booster, sodium taurodeoxycholate (TDC). First, a preliminary study was conducted to adjust the nanospray drying conditions. Then, formulations were prepared on the basis of a mixed factorial experimental design and further analyzed using Design Expert® software. Different responses were investigated: particle size, polydispersity index, spray rate, drying efficiency, and percent yield. The optimized formulation was further assessed for physical morphology using the scanning electron microscope, flowability, in vitro drug release, and in vivo brain cell uptake using confocal laser scanning microscopy. The promising formulation (F6), composed of equal ratio of PAA and TDC and 20 mg GAL, exhibited a particle size of 185.55 ± 4.3 nm, polydispersity index of 0.413 ± 0.02, and yield-value of 69.58 ± 5.82 %. It also displayed good flowability, complete drug release within 2 h, and enhanced in vivo fluorescent dye uptake and penetration in brain cells. The efficacy of the optimized formulation was examined using lipopolysaccharide-induced Alzheimer's in mice. Results revealed the advantageous influence of the optimized formulation (F6) through downregulation of NF-κβ, IL-1β and GFAP as well as upregulating TGF-1β in adult mice.

Interaction of polymers with bile salts - Impact on solubilisation and absorption of poorly water-soluble drugs

Formulating poorly soluble drugs with polymers in the form of solid dispersions has been widely used for improving drug dissolution. Endogenous surface-active species present in the gut, such as bile salts, lecithin and other phospholipids, have been shown to play a key role in facilitating lipids and poorly soluble drugs solubilisation in the gut. In this study, we examined the possible occurrence of interactions between a model bile salt, sodium taurocholate (NaTC), and model spray dried solid dispersions comprising piroxicam and Hydroxypropyl Methylcellulose (HPMC), a commonly used hydrophilic polymer for solid dispersion preparation. Solubility measurements revealed the good solubilisation effect of NaTC on the crystalline drug, which was enhanced by the addition of HPMC, and further boosted by the drug formulation into solid dispersion. The colloidal behaviour of the solid dispersions upon dissolution in biorelevant media, with and without NaTC, revealed the formation of NaTC-HPMC complexes and other mixed colloidal species. Cellular level drug absorption studies obtained using Caco-2 monolayers confirmed that the combination of drug being delivered by solid dispersion and the presence of bile salt and lecithin significantly contributed to the improved drug absorption. Together with the role of NaTC-HPMC complexes in assisting the drug solubilisation, our results also highlight the complex interplay between bile salts, excipients and drug absorption.

Self-assembly of bile salts and their mixed aggregates as building blocks for smart aggregates

The present communication offers a comprehensive overview of the self-assembly of bile salts emphasizing their mixed smart aggregates with a variety of amphiphiles. Using an updated literature survey, we have explored the dissimilar interactions of bile salts with different types of surfactants, phospholipids, ionic liquids, drugs, and a variety of natural and synthetic polymers. While assembling this review, special attention was also provided to the potency of bile salts to alter the size/shape of aggregates formed by several amphiphiles to use these aggregates for solubility improvement of medicinally important compounds, active pharmaceutical ingredients, and also to develop their smart delivery vehicles. A fundamental understanding of bile salt mixed aggregates will enable the development of new strategies for improving the bioavailability of drugs solubilized in newly developed potential hosts and to formulate smart aggregates of desired morphology for specific targeted applications. It enriches our existing knowledge of the distinct interactions exerted in mixed systems of bile salts with variety of amphiphiles. By virtue of this, researchers can get innovative ideas to construct novel nanoaggregates from bile salts by incorporating various amphiphiles that serve as a building block for smart aggregates for their numerous industrial applications.

Biocompatible phospholipid-based mixed micelles for posaconazole ocular delivery: Development, characterization, and in - vitro antifungal activity

Current study intended to prepare and evaluate phospholipid-based, mixed micelles (MMs) to improve the ocular delivery of posaconazole (POS), a broad-spectrum antifungal drug. For this, MMs based on egg phosphatidylcholine (EPC), as the main component, in combination with various bile salts (sodium cholate (NaC), sodium deoxycholate (NaDC), sodium taurocholate (NaTC)) or non-ionic surfactants (Pluronic® F-127, Pluronic® F-68, Tween 80, Labrasol® ALF, and d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS)) were prepared. Particle size, polydispersity index, zeta potential and entrapment efficiency were evaluated to optimize the composition and preparation method of the MMs. Finally, morphology, stability, in vitro release pattern, and in vitro antifungal activity of the optimized formulation were investigated. Among the prepared MMs, vesicles composed of EPC: TPGS with a molar ratio of 70:30, prepared by the thin-film hydration method, showed more appropriate features. Among the prepared MMs, vesicles composed of EPC: TPGS with a molar ratio of 70:30 showed more appropriate features, including an entrapment efficiency (EE) greater than 80%, spherical shape morphology, an average particle size of about 58 nm, desirable stability over a month, slow-release without a noticeable initial burst, and a significantly higher in vitro antifungal activity in comparison with the drug suspension. Therefore, this formulation was selected as the optimal MMs and could be considered as a promising carrier for topical ocular delivery of POS.

Effects of industrially produced 2-dimensional molybdenum disulfide materials in primary human basophils

MoS₂ has been increasingly used in place of graphene as a flexible and multifunctional 2D material in many biomedical applications such as cancer detection and drug delivery, which makes it crucial to evaluate downstream compatibility in human immune cells. Molybdenum is a component of stainless-steel stent implants and has previously been implicated in stent hypersensitivity. In view of this, it is important to ascertain the effect of MoS₂ on allergy-relevant cells. Basophils are a less commonly used immune cell type. Unlike mast cells, basophils can be easily derived from primary human blood and can act as a sentinel for allergy. However, merely testing any one type of MoS₂ in basophils could result in different biological results. We thus decided to compare 2D MoS₂ from the two companies BeDimensional© (BD) and Biograph Solutions (BS), manufactured with two different but commonly exploited methods (BD, deoxycholate surfactant in a high-pressure liquid exfoliation, and BS using glycine in ball-milling exfoliation) to elucidate immunological end-points common to both MoS₂ and to demonstrate the need for biological verification for end-users who may require a change of supplier. We report higher histamine production in human basophils with MoS₂. No effects on either surface basophil activation markers CD63 and CD203c or reactive oxygen species (ROS) production and cell viability were observed. However, different cytokine production patterns were evidenced. IL-6 and IL-1β but not TNF and GM-CSF were increased for both MoS₂. BS-MoS₂ increased IL-4, while BD-MoS₂ decreased IL-4 and increased IL-13. Molybdate ion itself only increased IL-1β and IL-4. Deoxycholate surfactant decreased viability at 18 h and increased ROS upon basophil activation. Therefore, these results demonstrate the safety of MoS₂ in human basophils in general and highlight the importance of considering manufacturer additives and variability when selecting and investigating 2D materials such as MoS₂.

Considering the Oral Bioavailability of Protein Kinase Inhibitors: Essential in Assessing the Extent of Drug-Drug Interaction and Improving Clinical Practice

Protein kinase inhibitors share pharmacokinetic (PK) pathways among themselves. They are all metabolized by several cytochromes P450 (CYP). For most of them, CYP3A4 is the predominant metabolic pathway. However, their oral bioavailability differs. For example, the oral bioavailability of imatinib has been estimated at nearly 100%, but that of ibrutinib averages 3% due to its high hepatic first-pass effect. Overall, the smaller the oral bioavailability, the larger its interindividual PK variability. Indeed, for drugs with low oral bioavailability, the extent of their absorption is an additional cause (along with elimination variability) of differences in drug exposure among patients. The impact of drug-drug interaction (DDI) also differs between drugs with low or high oral bioavailability. We describe and explain why the impact of CYP3A4 inhibitors and inducers is much greater for protein kinase inhibitors with low oral bioavailability. The effect of food on protein kinase inhibitors and DDIs corresponding to plasma protein binding will also be considered. Finally, the benefits of these concepts in clinical practice (including therapeutic drug monitoring) will be discussed. Overall, our main objective was to apply fundamental PK concepts to understanding the main clinical issues of these oral anticancer drugs.

Solubilization and Controlled Release Strategy of Poorly Water-Soluble Drugs

The processes of solubilization and controlled release of drugs that are poorly soluble in water are highly relevant in drug preformulation studies in pharmaceutical development [...]

Farnesoid X receptor agonist tropifexor attenuates cholestasis in a randomised trial in patients with primary biliary cholangitis

Background & Aims

The safety, tolerability, and efficacy of the non-bile acid farnesoid X receptor agonist tropifexor were evaluated in a phase II, double-blind, placebo-controlled study as potential second-line therapy for patients with primary biliary cholangitis (PBC) with an inadequate ursodeoxycholic acid response.

Methods

Patients were randomised (2:1) to receive tropifexor (30, 60, 90, or 150 μg) or matched placebo orally once daily for 28 days, with follow-up on Days 56 and 84. Primary endpoints were safety and tolerability of tropifexor and reduction in levels of γ-glutamyl transferase (GGT) and other liver biomarkers. Other objectives included patient-reported outcome measures using the PBC-40 quality-of-life (QoL) and visual analogue scale scores and tropifexor pharmacokinetics.

Results

Of 61 enrolled patients, 11, 9, 12, and 8 received 30-, 60-, 90-, and 150-μg tropifexor, respectively, and 21 received placebo; 3 patients discontinued treatment because of adverse events (AEs) in the 150-μg tropifexor group. Pruritus was the most frequent AE in the study (52.5% [tropifexor] vs. 28.6% [placebo]), with most events of mild to moderate severity. Decreases seen in LDL-, HDL-, and total-cholesterol levels at 60-, 90-, and 150 μg doses stabilised after treatment discontinuation. By Day 28, tropifexor caused 26-72% reduction in GGT from baseline at 30- to 150-μg doses (p <0.001 at 60-, 90-, and 150-μg tropifexor vs. placebo). Day 28 QoL scores were comparable between the placebo and tropifexor groups. A dose-dependent increase in plasma tropifexor concentration was observed, with 5- to 5.55-fold increases in AUC_0-8h and C_max between 30- and 150-μg doses.

Conclusions

Tropifexor showed improvement in cholestatic markers relative to placebo, predictable pharmacokinetics, and an acceptable safety-tolerability profile, thereby supporting its potential further clinical development for PBC.

Lay summary

The bile acid ursodeoxycholic acid (UDCA) is the standard-of-care therapy for primary biliary cholangitis (PBC), but approximately 40% of patients have an inadequate response to this therapy. Tropifexor is a highly potent non-bile acid agonist of the farnesoid X receptor that is under clinical development for various chronic liver diseases. In the current study, in patients with an inadequate response to UDCA, tropifexor was found to be safe and well tolerated, with improved levels of markers of bile duct injury at very low (microgram) doses. Itch of mild to moderate severity was observed in all groups including placebo but was more frequent at the highest tropifexor dose.

Clinical Trials Registration

This study is registered at ClinicalTrials.gov (NCT02516605).

Microfluidic Manufacture of Lipid-Based Nanomedicines

Nanoparticulate technologies have revolutionized drug delivery allowing for passive and active targeting, altered biodistribution, controlled drug release (temporospatial or triggered), enhanced stability, improved solubilization capacity, and a reduction in dose and adverse effects. However, their manufacture remains immature, and challenges exist on an industrial scale due to high batch-to-batch variability hindering their clinical translation. Lipid-based nanomedicines remain the most widely approved nanomedicines, and their current manufacturing methods remain discontinuous and face several problems such as high batch-to-batch variability affecting the critical quality attributes (CQAs) of the product, laborious multistep processes, need for an expert workforce, and not being easily amenable to industrial scale-up involving typically a complex process control. Several techniques have emerged in recent years for nanomedicine manufacture, but a paradigm shift occurred when microfluidic strategies able to mix fluids in channels with dimensions of tens of micrometers and small volumes of liquid reagents in a highly controlled manner to form nanoparticles with tunable and reproducible structure were employed. In this review, we summarize the recent advancements in the manufacturing of lipid-based nanomedicines using microfluidics with particular emphasis on the parameters that govern the control of CQAs of final nanomedicines. The impact of microfluidic environments on formation dynamics of nanomaterials, and the application of microdevices as platforms for nanomaterial screening are also discussed.

Inhibition of microbial deconjugation of micellar bile acids protects against intestinal permeability and liver injury

Altered host-microbe interactions and increased intestinal permeability have been implicated in disease pathogenesis. However, the mechanisms by which intestinal microbes affect epithelial barrier integrity remain unclear. Here, we investigate the impact of bacterial metabolism of host-produced bile acid (BA) metabolites on epithelial barrier integrity. We observe that rats fed a choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD) exhibit reduced intestinal abundance of host-produced conjugated BAs at early time points, coinciding with increased gut permeability. We show that in vitro, conjugated BAs protect gut epithelial monolayers from damage caused by bacterially produced unconjugated BAs through micelle formation. We then demonstrate that inhibition of bacterial BA deconjugation with a small-molecule inhibitor prevents the development of pathologic intestinal permeability and hepatic inflammation in CDAHFD-fed rats. Our study identifies a signaling-independent, physicochemical mechanism for conjugated BA-mediated protection of epithelial barrier function and suggests that rational manipulation of microbial BA metabolism could be leveraged to regulate gut barrier integrity.

Bilosomes as Nanoplatform for Oral Delivery and Modulated In Vivo Antimicrobial Activity of Lycopene

Owing to the disseminating resistance among pathogenic bacteria, especially Klebsiella pneumoniae, there is a high need for alternate compounds with antibacterial activity. Herein, lycopene was isolated from Lycopersicon esculentum L. Molecular docking approach was employed to explore lycopene binding affinity to selected vital proteins of K. pneumoniae with the binding mechanisms being investigated. This proposed a promising antibacterial activity of lycopene. However, the pharmacological use of lycopene is hampered by its poor solubility and limited oral bioavailability. Accordingly, bilosomes were fabricated for oral lycopene delivery. The computed entrapment efficiency, mean vesicular size, and zeta potential values for the optimized formulation were 93.2 ± 0.6%, 485.8 ± 35.3 nm, and −38.3 ± 4, respectively. In vitro drug release studies revealed controlled lycopene release from constructed bilosomes, with the drug liberation being based on the Higuchi kinetics model. Transmission electron microscopic evaluation of bilosomes revealed spherical nanovesicles free from aggregates. Moreover, the in vitro and in vivo antibacterial activity of lycopene and its constructed formulations against multidrug-resistant K. pneumoniae isolates were explored. The optimized bilosomes exhibited the lowest minimum inhibitory concentrations ranging from 8 to 32 µg/mL. In addition, scanning electron microscopy revealed remarkable deformation and lysis of the bilosomes-treated bacterial cells. Regarding in vivo investigation, a lung infection model in mice was employed. The tested bilosomes reduced the inflammation and congestion in the treated mice’s lung tissues, resulting in normal-sized bronchioles and alveoli with very few congested vessels. In addition, it resulted in a significant reduction in pulmonary fibrosis. In conclusion, this study investigated the potential activity of the naturally isolated lycopene in controlling infections triggered by multidrug-resistant K. pneumoniae isolates. Furthermore, it introduced bilosomes as a promising biocompatible nanocarrier for modulation of oral lycopene delivery and in vivo antimicrobial activity.

Intestinal Absorption Study: Challenges and Absorption Enhancement Strategies in Improving Oral Drug Delivery

The oral route is the most common and practical means of drug administration, particularly from a patient’s perspective. However, the pharmacokinetic profile of oral drugs depends on the rate of drug absorption through the intestinal wall before entering the systemic circulation. However, the enteric epithelium represents one of the major limiting steps for drug absorption, due to the presence of efflux transporters on the intestinal membrane, mucous layer, enzymatic degradation, and the existence of tight junctions along the intestinal linings. These challenges are more noticeable for hydrophilic drugs, high molecular weight drugs, and drugs that are substrates of the efflux transporters. Another challenge faced by oral drug delivery is the presence of first-pass hepatic metabolism that can result in reduced drug bioavailability. Over the years, a wide range of compounds have been investigated for their permeation-enhancing effect in order to circumvent these challenges. There is also a growing interest in developing nanocarrier-based formulation strategies to enhance the drug absorption. Therefore, this review aims to provide an overview of the challenges faced by oral drug delivery and selected strategies to enhance the oral drug absorption, including the application of absorption enhancers and nanocarrier-based formulations based on in vitro, in vivo, and in situ studies.

Functional, Diagnostic and Therapeutic Aspects of Bile

Bile is a unique body fluid synthesized in our liver. Enterohepatic circulation preserves bile in our body through its efficient synthesis, transport, absorption, and reuptake. Bile is the main excretory route for bile salts, bilirubin, and potentially harmful exogenous lipophilic substances. The primary way of eliminating cholesterol is bile. Although bile has many organic and inorganic contents, bile acid is the most physiologically active component. Bile acids have a multitude of critical physiologic functions in our body. These include emulsification of dietary fat, absorption of fat and fat-soluble vitamins, maintaining glucose, lipid, and energy homeostasis, sustenance of intestinal epithelial integrity and epithelial cell proliferation, reducing inflammation in the intestine, and prevention of enteric infection due to its antimicrobial properties. But bile acids can be harmful in certain altered conditions like cholecystectomy, terminal ileal disease or resection, cholestasis, duodenogastric bile reflux, duodenogastroesophageal bile reflux, and bile acid diarrhea. Bile acids can have malignant potentials as well. There are also important diagnostic and therapeutic roles of bile acid and bile acid modulation.

Bile acid-based advanced drug delivery systems, bilosomes and micelles as novel carriers for therapeutics

Diabetes mellitus affects almost half a billion patients worldwide and results from either destruction of β-cells responsible for insulin secretion or increased tissue resistance to insulin stimulation and the reduction of glycemic control. Novel drug delivery systems can improve treatment efficacy in diabetic patients. The low aqueous solubility of most oral antidiabetic drugs decreases drug bioavailability; therefore, there is a demand for the use of novel methods to overcome this issue. The application of bile acids mixed micelles and bilosomes can provide an enhancement in drug efficacy. Bile acids are amphiphilic steroidal molecules that contain a saturated tetracyclic hydrocarbon cyclopentanoperhydrophenanthrene ring, and consist of three 6-membered rings and a 5-membered ring, a short aliphatic side chain, and a tough steroid nucleus. This review offers a comprehensive and informative data focusing on the great potential of bile acid, their salts, and their derivatives for the development of new antidiabetic drug delivery system.

Development of a Novel Bilosomal System for Improved Oral Bioavailability of Sertraline Hydrochloride: Formulation Design, In Vitro Characterization, and Ex Vivo and In Vivo Studies

This study was proposed to develop an optimized sertraline hydrochloride (SER)-loaded bilosomal system and evaluate its potential for enhancement of drug oral bioavailability. A full 2³ factorial design was used to prepare SER-loaded bilosomal dispersions by thin film hydration using span 60, cholesterol (CHL), and sodium deoxycholate (SDC). The investigated factors included the total concentration of span 60 and CHL (X₁), span 60:CHL molar ratio (X₂), and SER:SDC molar ratio (X₃). The studied responses were entrapment efficiency (EE%) (Y₁), zeta potential (Y₂), particle size (Y₃), and in vitro % drug released at 2 (Y₄), 8 (Y₅), and 24 h (Y₆). The selected optimal bilosomal dispersion (N1) composition was 0.5% w/v (X₁), 1:1 (X₂), and 1:2 (X₃). Then, N1 was freeze dried into FDN1 that compared with pure SER for in vitro drug release, ex vivo permeation through rabbit intestine, and in vivo absorption in rats. Moreover, storage effect on FDN1 over 3 months was assessed. The optimal dispersion (N1) showed 68 ± 0.7% entrapment efficiency, - 41 ± 0.78 mV zeta potential, and 377 ± 19 nm particle size. The freeze-dried form (FDN1) showed less % drug released in simulated gastric fluids with remarkable sustained SER release up to 24 h compared to pure SER. Moreover, FDN1 showed good stability, fivefold enhancement in SER permeation through rabbit intestine, and 222% bioavailability enhancement in rats' in vivo absorption study compared to pure SER. The SER-loaded bilosomal system (FDN1) could improve SER oral bioavailability with minimization of gastrointestinal side effects.

Self-assembled bilosomes with stimuli-responsive properties as bioinspired dual-tunable nanoplatform for pH/temperature-triggered release of hybrid cargo

The rapid development of colloid chemistry has raised the possibility of using nanocarriers for the targeted delivery and the controlled drug release at predictable locations to reduce side effects and enhance therapeutic efficacy. In the present work, we focused on the influence of temperature and pH upon in vitro controlled phytochemical/dye-release from a modified bilosome. Drug molecules can affect the properties of nanocarriers, so the effect of encapsulated bioactive compounds on nanoparticle structure has been investigated. The self-assembly process of bioinspired components (i.e., phospholipids, bile salts, and cholesterol), and biocompatible polymeric triblock materials, made it possible to receive structures with a size below 100 nm, demonstrated good capacity for active cargo encapsulation. Differential scanning calorimetry studies showed the possibility of the payloads' interaction with the bilosomes structure. A highly lipophilic compound, such as curcumin, can weaken hydrophobic interactions between the acyl chains of phospholipids, leading to a more flexible membrane. The in vitro release profiles have proved that both solubilities of the therapeutic substances and various environmental conditions affect the release rate of the hybrid cargo. Overall, the obtained double-loaded bilosomes represent a promising bioinspired nanoplatform for oral, intravenous, and topical drug delivery in future biomedical applications.

Cholestasis alters brain lipid and bile acid composition and compromises motor function in neonatal piglets

Infants with neonatal cholestasis are prone to neurodevelopmental deficits, however, the underlying pathogenesis is unclear. Lipid malabsorption and accumulation of potentially neurotoxic molecules in the blood such as bile acids are important yet relatively unexplored pathways. Here, we developed a translational piglet model to understand how the molecular bile acid and lipid composition of the brain is affected by this disease and relates to motor function. Piglets (8-days old) had bile duct ligation or sham surgery and were fed a formula diet for 3 weeks. Alongside sensory-motor deficits observed in bile duct-ligated animals, we found a shift toward a more hydrophilic and conjugated bile acid profile in the brain. Additionally, comprehensive lipidomics of the cerebellum revealed a decrease in total lipids including phosphatidylinositols and phosphatidylserines and increases in lysophospholipid species. This was paralleled by elevated cerebellar expression of genes related to inflammation and tissue damage albeit without significant impact on the brain transcriptome. This study offers new insights into the developing brain's molecular response to neonatal cholestasis indicating that bile acids and lipids may contribute in mediating motor deficits.

N-Cholyl d-Penicilamine Micelles Templated Red Light-Emitting Silver Nanoclusters: Fluorometric Sensor for S2- Ions and Bioimaging Application Using Zebrafish Model

Red-light-emitting silver nanoclusters (AgNCs) are recently emerged as a promising nanoprobe in the field of biomedical applications, because of their attractive properties, including brightness, luminescence stability, and better biocompatibility. In this report, we have developed highly water-soluble red-light-emitting AgNCs by using N-cholyl d-penicilamine (NCPA) as a biosurfactant at above the critical micelle concentration (CMC) at room temperature. Moreover, the NCPA was initially synthesized by demonstrating the reaction between cholic acid and d-penicilamine via a simple coupling reaction strategy. The primary and secondary critical micellar concentration (CMC) of NCPA surfactant was measured using pyrene (1 × 10^-6 M) as a fluorescent probe, and the values were found to be 3.18 and 10.6 mM, respectively. Steady-state fluorescence measurements reveal that the prepared AgNCs shows the excitation and emission maxima at 365 and 672 nm, respectively, with a large Stokes shift (307 nm). The average lifetime measurements and quantum yield of the AgNCs were calculated to be 143.43 ns and 16.34%, respectively. Also, the red luminescent NCPA-templated AgNCs was synthesized in various protic and aprotic polar solvents, among which DMF and DMSO exhibit bright emission at longer wavelength as synthesized in aqueous medium. At higher concentration of AgNO₃, bright luminescent and highly stable solid AgNCs was obtained with excitation and emission maxima at 607 and 711 nm, respectively. Furthermore, the synthesized AgNCs has been successfully utilized as a fluorescent probe for selective and sensitive detection of S^2- ions at nanomolar level in water samples, showing its potential applicability for the detection of S^2- ions in drinking, river, and tap water samples. Finally, toxicity and bioimaging studies of NCPA-templated AgNCs was demonstrated using zebrafish as in vivo model, showing no significant toxicity up to 200 μL/mL. The AgNCs-stained embryos exhibited red fluorescence with high intensity, which shows that AgNCs are stable in a living system.

Engineering cell-based microstructures to study the effect of structural complexity on in vitro bioaccessibility of a lipophilic bioactive compound

A fundamental understanding of the influence of food microstructures on the bioaccessibility of micronutrients is vital for the design of functionally efficient foods. This study investigated the effect of microstructural features of model foods on the bioaccessibility of a bioactive compound - curcumin, using a unique bottom-up approach. In this approach, individual yeast cells with infused curcumin were coated with oppositely charged polyelectrolytes: first in poly(diallyl-dimethylammonium chloride), then in dextran sulfate or alginate, and assembled electrostatically to generate two types of cell clusters. These cell clusters were embedded in an alginate film to form a tissue-like structure. The influence of cell clustering and extracellular matrix on the release of encapsulated curcumin from cell-based microcarriers during simulated digestion was evaluated. Cell clusters that maintained their integrity during in vitro simulated digestion retained up to twice as much curcumin upon addition of the simulated intestinal fluid (SIF) compared to single cells during the first hour of intestinal digestion. Despite significant differences in the release profile, no spatial heterogeneity of curcumin release across a cell cluster was observed with the imaging measurements. Embedding single cells or cell clusters in calcium-crosslinked alginate films resulted in another 20-30% increase in curcumin retention and a prolonged barrier effect for more than 2 hours compared to microstructures without the films. This bottom-up approach of engineering cell-based tissue-like structures proves to be an effective method for investigating the contributions of microstructural properties of food matrices to influencing bioaccessibility of bioactives and guides future development of functional food materials.

Dual Functionality of Bile Acid: Physical Stabilization of Drugs in the Amorphous Form and Solubility Enhancement in Solution

Drugs containing an amino aromatic nitrogen moiety were stabilized in the amorphous form by the surfactant cholic acid (CA). Coamorphous systems of lamotrigine (LAM), pyrimethamine (PYR), and trimethoprim (TRI) were each prepared with CA. Drug-CA interactions, investigated by IR and solid-sate NMR spectroscopy, revealed deprotonation of the carboxylic acid group in CA and the protonation of the most basic nitrogen of the drug. The coamorphous systems exhibited exceptional physical stability and resisted crystallization at (i) elevated temperatures (>100 °C) and (ii) accelerated storage conditions, 40 °C/75% relative humidity for 15 months. The dissolution performance of each coamorphous system was compared with the respective crystalline drug based on the area under the curve (AUC) of the concentration-time profiles. A 25-fold increase in AUC was observed in the PYR-CA coamorphous system. The solubility enhancement is attributed not only due to drug amorphization but also due to solubilization by CA. The supramolecular synthon approach, through a drug-CA interaction, yielded physically stable coamorphous systems with enhanced aqueous drug solubility.

Superior Bioavailability of a Novel Lutein and Zeaxanthin Formulation in Healthy Human Subjects

Introduction

Lutein (L) and zeaxanthin (Z) are carotenoids that are found in the macula of the human eye and are known to improve visual functions. However, poor bioavailability of supplemental L and Z poses a challenge to achieving significant benefits after consumption. We developed a novel patented formulation of L and Z (Ocusorb^®) and demonstrated the improved bioavailability in a pharmacokinetic clinical study.

Methods

Ninety adult human volunteers were recruited in this randomized, double-blind, parallel, comparative bioavailability study. Volunteers were randomly assigned to receive single dose of 10 mg lutein and 2 mg zeaxanthin from test (LZO) or reference (LZC) formulations after breakfast. Blood samples were collected pre-dose at − 48, − 24, and 0 h and at 2, 4, 6, 8, 10, 12, 16, 20, 24, 48, and 72 h post-dose. Serum concentrations of L and Z were quantified by using a validated HPLC method. The LZO and LZC formulations were compared for L and Z on the basis of C_max, AUC_0–72, and AUC_0–t.

Results

All 90 subjects completed the study. The LZO group demonstrated significantly higher levels of L and Z in serum at several time points as compared to LZC group. The LZO group showed significantly higher bioavailability for lutein (2.5 times higher C_max, 2.9 times higher AUC_0–72, and 3.2 times higher AUC_0–t) and zeaxanthin (1.8 times higher C_max, 2.2 times higher AUC_0–72, and AUC_0–t) as compared to the LZC group. No safety issues were reported.

Conclusion

The study results show superior bioavailability of lutein and zeaxanthin from our novel LZO formulation as compared to LZC. The enhanced bioavailability from the LZO formulation can be advantageous for individuals looking to quickly improve their L and Z status and enhance their vision performance.

Trial Registration

http://ctri.nic.in/. Identifier: CTRI/2019/11/022082.

Bile Acids Transporters of Enterohepatic Circulation for Targeted Drug Delivery

Bile acids (BAs) are important steroidal molecules with a rapidly growing span of applications across a variety of fields such as supramolecular chemistry, pharmacy, and biomedicine. This work provides a systematic review on their transport processes within the enterohepatic circulation and related processes. The focus is laid on the description of specific or less-specific BA transport proteins and their localization. Initially, the reader is provided with essential information about BAs′ properties, their systemic flow, metabolism, and functions. Later, the transport processes are described in detail and schematically illustrated, moving step by step from the liver via bile ducts to the gallbladder, small intestine, and colon; this description is accompanied by descriptions of major proteins known to be involved in BA transport. Spillage of BAs into systemic circulation and urine excretion are also discussed. Finally, the review also points out some of the less-studied areas of the enterohepatic circulation, which can be crucial for the development of BA-related drugs, prodrugs, and drug carrier systems.

Using Nuclear Magnetic Resonance Spectroscopy to Probe Hydrogels Formed by Sodium Deoxycholate

Hydrogels of bile acids and their salts are promising materials for drug delivery, cellular immobilization, and other applications. However, these hydrogels are poorly understood at the molecular level, and further study is needed to allow improved materials to be created by design. We have used NMR spectroscopy to probe hydrogels formed from mixtures of formic acid and sodium deoxycholate (NaDC), a common bile acid salt. By assaying the ratio of deoxycholate molecules that are immobilized as part of the fibrillar network of the hydrogels and those that can diffuse, we have found that 65% remain free under typical conditions. The network appears to be composed of both the acid and salt forms of deoxycholate, possibly because a degree of charge inhibits excessive aggregation and precipitation of the fibrils. Spin-spin relaxation times provided a molecular-level estimate of the temperature of gel-sol transition (42 °C), which is virtually the same as the value determined by analyzing macroscopic parameters. Saturation transfer difference (STD) NMR spectroscopy established that formic acid, which is present mainly as formate, is not immobilized as part of the gelating network. In contrast, HDO interacts with the network, which presumably has a surface with exposed hydrophilic groups that form hydrogen bonds with water. Moreover, the STD NMR experiments revealed that the network is a dynamic entity, with molecules of deoxycholate associating and dissociating reversibly. This exchange appears to occur preferentially by contact of the hydrophobic edges or faces of free molecules of deoxycholate with those of molecules immobilized as components of the network. In addition, DOSY experiments revealed that gelation has little effect on the diffusion of free NaDC and HDO.

Antisense Oligonucleotides Conjugated with Lipophilic Compounds: Synthesis and In Vitro Evaluation of Exon Skipping in Duchenne Muscular Dystrophy

Our groups previously reported that conjugation at 3′-end with ursodeoxycholic acid (UDCA) significantly enhanced in vitro exon skipping properties of ASO 51 oligonucleotide targeting the human DMD exon 51. In this study, we designed a series of lipophilic conjugates of ASO 51, to explore the influence of the lipophilic moiety on exon skipping efficiency. To this end, three bile acids and two fatty acids have been derivatized and/or modified and conjugated to ASO 51 by automatized solid phase synthesis. We measured the melting temperature (T_m) of lipophilic conjugates to evaluate their ability to form a stable duplex with the target RNA. The exon skipping efficiency has been evaluated in myogenic cell lines first in presence of a transfection agent, then in gymnotic conditions on a selection of conjugated ASO 51. In the case of 5′-UDC-ASO 51, we also evaluated the influence of PS content on exon skipping efficiency; we found that it performed better exon skipping with full PS linkages. The more efficient compounds in terms of exon skipping were found to be 5′-UDC- and 5′,3′-bis-UDC-ASO 51.

Gut Microbiota as the Potential Mechanism to Mediate Drug Metabolism Under High-Altitude Hypoxia

BACKGROUND

The characteristics of pharmacokinetics and the activity and expression of drug-metabolizing enzymes and transporters significantly change under a high-altitude hypoxic environment. Gut microbiota is an important factor affecting the metabolism of drugs through direct or indirect effects, changing the bioavailability, biological activity, or toxicity of drugs and further affecting the efficacy and safety of drugs in vivo. A high-altitude hypoxic environment significantly changes the structure and diversity of gut microbiota, which may play a key role in drug metabolism under a high-altitude hypoxic environment.

METHODS

An investigation was carried out by reviewing published studies to determine the role of gut microbiota in the regulation of drug-metabolizing enzymes and transporters. Data and information on expression change in gut microbiota, drug-metabolizing enzymes and transporters under a high-altitude hypoxic environment were explored and proposed.

RESULTS

High-altitude hypoxia is an important environmental factor that can adjust the structure of the gut microbiota and change the diversity of intestinal microbes. It was speculated that the gut microbiota could regulate drug-metabolizing enzymes through two potential mechanisms, the first being through direct regulation of the metabolism of drugs in vivo and the second being indirect, i.e., through the regulation of drug-metabolizing enzymes and transporters, thereby affecting the activity of drugs.

CONCLUSION

This article reviews the effects of high-altitude hypoxia on the gut microbiota and the effects of these changes on drug metabolism.

Biguanide Pharmaceutical Formulations and the Applications of Bile Acid-Based Nano Delivery in Chronic Medical Conditions

Biguanides, particularly the widely prescribed drug metformin, have been marketed for many decades and have well-established absorption profiles. They are commonly administered via the oral route and, despite variation in oral uptake, remain commonly prescribed for diabetes mellitus, typically type 2. Studies over the last decade have focused on the design and development of advanced oral delivery dosage forms using bio nano technologies and novel drug carrier systems. Such studies have demonstrated significantly enhanced delivery and safety of biguanides using nanocapsules. Enhanced delivery and safety have widened the potential applications of biguanides not only in diabetes but also in other disorders. Hence, this review aimed to explore biguanides’ pharmacokinetics, pharmacodynamics, and pharmaceutical applications in diabetes, as well as in other disorders.

Synthesis and Biological Investigation of Bile Acid-Paclitaxel Hybrids

Chenodeoxycholic acid and ursodeoxycholic acid (CDCA and UDCA, respectively) have been conjugated with paclitaxel (PTX) anticancer drugs through a high-yield condensation reaction. Bile acid-PTX hybrids (BA-PTX) have been investigated for their pro-apoptotic activity towards a selection of cancer cell lines as well as healthy fibroblast cells. Chenodeoxycholic-PTX hybrid (CDC-PTX) displayed cytotoxicity and cytoselectivity similar to PTX, whereas ursodeoxycholic-PTX hybrid (UDC-PTX) displayed some anticancer activity only towards HCT116 colon carcinoma cells. Pacific Blue (PB) conjugated derivatives of CDC-PTX and UDC-PTX (CDC-PTX-PB and UDC-PTX-PB, respectively) were also prepared via a multistep synthesis for evaluating their ability to enter tumor cells. CDC-PTX-PB and UDC-PTX-PB flow cytometry clearly showed that both CDCA and UDCA conjugation to PTX improved its incoming into HCT116 cells, allowing the derivatives to enter the cells up to 99.9%, respect to 35% in the case of PTX. Mean fluorescence intensity analysis of cell populations treated with CDC-PTX-PB and UDC-PTX-PB also suggested that CDC-PTX-PB could have a greater ability to pass the plasmatic membrane than UDC-PTX-PB. Both hybrids showed significant lower toxicity with respect to PTX on the NIH-3T3 cell line.

Influence of Bile Acids in Hydrogel Pharmaceutical Formulations on Dissolution Rate and Permeation of Clindamycin Hydrochloride

Clindamycin hydrochloride is a widely used antibiotic for topical use, but its main disadvantage is poor skin penetration. Therefore, new approaches in the development of clindamycin topical formulations are of great importance. We aimed to investigate the effects of the type of gelling agent (carbomer and sodium carmellose), and the type and concentration of bile acids as penetration enhancers (0.1% and 0.5% of cholic and deoxycholic acid), on clindamycin release rate and permeation in a cellulose membrane in vitro model. Eight clindamycin hydrogel formulations were prepared using a 2³ full factorial design, and they were evaluated for physical appearance, pH, drug content, drug release, and permeability parameters. Although formulations with carbomer as the gelling agent exerted optimal sensory properties, carmellose sodium hydrogels had significantly higher release rates and permeation of clindamycin hydrochloride. The bile acid enhancement factors were higher in carbomer gels, and cholic acid exerted more pronounced permeation-enhancing effects. Since the differences in the permeation parameters of hydrogels containing cholic acid in different concentrations were insignificant, its addition in a lower concentration is more favorable. The hydrogel containing carmellose sodium as a gelling agent and 0.1% cholic acid as a penetration enhancer can be considered as the formulation of choice.

Cholate Conjugated Cationic Polymers for Regulation of Actin Dynamics

Cytoskeletal movement is a compulsory necessity for proper cell functioning and is largely controlled by actin filament dynamics. The actin dynamics can be finetuned by various natural and artificial materials...

New Deoxycholic Acid Derived Tyrosyl-DNA Phosphodiesterase 1 Inhibitors Also Inhibit Tyrosyl-DNA Phosphodiesterase 2

A series of deoxycholic acid (DCA) amides containing benzyl ether groups on the steroid core were tested against the tyrosyl-DNA phosphodiesterase 1 (TDP1) and 2 (TDP2) enzymes. In addition, 1,2,4- and 1,3,4-oxadiazole derivatives were synthesized to study the linker influence between a para-bromophenyl moiety and the steroid scaffold. The DCA derivatives demonstrated promising inhibitory activity against TDP1 with IC₅₀ in the submicromolar range. Furthermore, the amides and the 1,3,4-oxadiazole derivatives inhibited the TDP2 enzyme but at substantially higher concentration. Tryptamide 5 and para-bromoanilide 8 derivatives containing benzyloxy substituent at the C-3 position and non-substituted hydroxy group at C-12 on the DCA scaffold inhibited both TDP1 and TDP2 as well as enhanced the cytotoxicity of topotecan in non-toxic concentration in vitro. According to molecular modeling, ligand 5 is anchored into the catalytic pocket of TDP1 by one hydrogen bond to the backbone of Gly458 as well as by π–π stacking between the indolyl rings of the ligand and Tyr590, resulting in excellent activity. It can therefore be concluded that these derivatives contribute to the development of specific TDP1 and TDP2 inhibitors for adjuvant therapy against cancer in combination with topoisomerase poisons.

Synthesis and Exon-Skipping Properties of a 3'-Ursodeoxycholic Acid-Conjugated Oligonucleotide Targeting DMD Pre-mRNA: Pre-Synthetic versus Post-Synthetic Approach

Steric blocking antisense oligonucleotides (ASO) are promising tools for splice modulation such as exon-skipping, although their therapeutic effect may be compromised by insufficient delivery. To address this issue, we investigated the synthesis of a 20-mer 2'-OMe PS oligonucleotide conjugated at 3'-end with ursodeoxycholic acid (UDCA) involved in the targeting of human DMD exon 51, by exploiting both a pre-synthetic and a solution phase approach. The two approaches have been compared. Both strategies successfully provided the desired ASO 51 3'-UDC in good yield and purity. It should be pointed out that the pre-synthetic approach insured better yields and proved to be more cost-effective. The exon skipping efficiency of the conjugated oligonucleotide was evaluated in myogenic cell lines and compared to that of unconjugated one: a better performance was determined for ASO 51 3'-UDC with an average 9.5-fold increase with respect to ASO 51.

Pharmaceutical formulation and polymer chemistry for cell encapsulation applied to the creation of a lab-on-a-chip bio-microsystem

Microencapsulation of formulation designs further expands the field and offers the potential for use in developing bioartificial organs via cell encapsulation. Combining formulation design and encapsulation requires ideal excipients to be determined. In terms of cell encapsulation, an environment which allows growth and functionality is paramount to ensuring cell survival and incorporation into a bioartificial organ. Hence, excipients are examined for both individual properties and benefits, and compatibility with encapsulated active materials. Polymers are commonly used in microencapsulation, offering protection from the immune system. Bile acids are emerging as a tool to enhance delivery, both biologically and pharmaceutically. Therefore, this review will focus on bile acids and polymers in formulation design via microencapsulation, in the field of bioartificial organ development.

Bile acid-permeation enhancement for inner ear cochlear drug - pharmacological uptake: bio-nanotechnologies in chemotherapy-induced hearing loss

Ototoxicity is the damage to inner ear sensory epithelia due to exposure to certain medications and chemicals. This occurs when toxins enter the tightly controlled inner ear environment inducing hair cell death, resulting in hearing loss. Recent studies have explored hydrogel-based bio-nanotechnologies and new drug delivery formulations to prevent drug-induced hearing loss, with much attention given to administration of antioxidant drugs. Bile acids have been recognized as promising excipients due to their biocompatibility and unique physiochemical properties. As yet bile acids have not been explored in improving drug delivery to the inner ear despite improving drug stability and delivery in other systems and demonstrating positive biological effects in their own right.

Metronomic delivery of orally available pemetrexed-incorporated colloidal dispersions for boosting tumor-specific immunity

In this study, we developed oral pemetrexed (PMX) for metronomic dosing to enhance antitumor immunity. PMX was electrostatically complexed with positively charged lysine-linked deoxycholic acid (DL) as an intestinal permeation enhancer, forming PMX/DL, to enhance its intestinal permeability. PMX/DL was also incorporated into a colloidal dispersion (CD) comprised of the block copolymer of poly(ethylene oxide) and poly(propylene oxide), and caprylocaproyl macrogol-8 glycerides (PMX/DL-CD). CD-containing PMX/DL complex in a 1:1 molar ratio [PMX/DL(1:1)-CD] showed 4.66- and 7.19-fold greater permeability than free PMX through the Caco-2 cell monolayer and rat intestine, respectively. This resulted in a 282% improvement in oral bioavailability in rats. In addition, low-dose metronomic PMX led to more immunogenic cell death in CT26.CL25 cells compared to high PMX concentrations at the maximum tolerated dose. In CT26.CL25 tumor-bearing mice, oral metronomic PMX/DL-CD elicited greater antitumor immunity not only by enhancing the number of tumor-infiltrating lymphocytes but also by suppressing T cell functions. Oral PMX/DL-CD substantially increased programmed cell death protein ligand-1 (PD-L1) expression on tumor cells compared to the control and PMX-IV groups. This increased antitumor efficacy in combination with anti-programmed cell death protein-1 (aPD-1) antibody in terms of tumor rejection and immunological memory compared to the combination of PMX-IV and aPD-1. These results suggest that oral metronomic scheduling of PMX/DL-CD in combination with immunotherapy has synergistic antitumor effects.