Lack of effect of β-cyclodextrin and its water-soluble derivatives on in vitro drug transport across rat intestinal epithelium

Hypoxia-tolerant apical-out intestinal organoids to model host-microbiome interactions

Microbiome is an integral part of the gut and is essential for its proper function. Imbalances of the microbiota can be devastating and have been linked with several gastrointestinal conditions. Current gastrointestinal models do not fully reflect the in vivo situation. Thus, it is important to establish more advanced in vitro models to study host-microbiome/pathogen interactions. Here, we developed for the first time an apical-out human small intestinal organoid model in hypoxia, where the apical surface is directly accessible and exposed to a hypoxic environment. These organoids mimic the intestinal cell composition, structure and functions and provide easy access to the apical surface. Co-cultures with the anaerobic strains Lactobacillus casei and Bifidobacterium longum showed successful colonization and probiotic benefits on the organoids. These novel hypoxia-tolerant apical-out small intestinal organoids will pave the way for unraveling unknown mechanisms related to host-microbiome interactions and serve as a tool to develop microbiome-related probiotics and therapeutics.

PSC-derived intestinal organoids with apical-out orientation as a tool to study nutrient uptake, drug absorption and metabolism

Intestinal organoids recapitulate many features of the in vivo gastrointestinal tract and have revolutionized in vitro studies of intestinal function and disease. However, the restricted accessibility of the apical surface of the organoids facing the central lumen (apical-in) limits studies related to nutrient uptake and drug absorption and metabolism. Here, we demonstrate that pluripotent stem cell (PSC)-derived intestinal organoids with reversed epithelial polarity (apical-out) can successfully recapitulate tissue-specific functions. In particular, these apical-out organoids show strong epithelial barrier formation with all the major junctional complexes, nutrient transport and active lipid metabolism. Furthermore, the organoids express drug-metabolizing enzymes and relevant apical and basolateral transporters. The scalable and robust generation of functional, apical-out intestinal organoids lays the foundation for a completely new range of organoid-based high-throughput/high-content in vitro applications in the fields of nutrition, metabolism and drug discovery.

Promoting effect of the Maillard reaction products produced during the stir-frying process of Hordei Fructus Germinatus on the intestinal absorption of active ingredients in Hordei Fructus Germinatus

This study was designed to evaluate the absorption promoting capacity of Maillard Reaction Products (MRPs) produced during the stir-frying process of Hordei Fructus Germinatus on catechin, ferulic acid, quercetin and kaempferol by the ex vivo rat everted gut sac model, in situ single-pass intestinal perfusion model and the whole animal model. Moreover, verapamil, EDTA and mannitol were used for determining the transport mechanism of catechin, ferulic acid, quercetin and kaempferol. The tight junction (TJ) proteins including zonula occudens-1(ZO-1) and claudin-1 were chosen to investigate the promoting mechanism of MRPs by quantitative real-time PCR (qRT-PCR) and western blot analyses. The results showed that the MRPs produced during the stir-frying process of Hordei Fructus Germinatus could improve the intestinal absorption of catechin, ferulic acid, quercetin and kaempferol. And the absorption-promoting effect of MRPs was related to chelating effect and the reduced expression of claudin-1 and ZO-1. Our results suggested that MRPs could be promising oral absorption promoters, which might be another processing mechanism of Hordei Fructus Germinatus.

Solid Lipid Nanoparticles as Formulative Strategy to Increase Oral Permeation of a Molecule Active in Multidrug-Resistant Tuberculosis Management

The role of mycobacterial efflux pumps in drug-resistant tuberculosis has been widely reported. Recently, a new compound, named SS13, has been synthesized, and its activity as a potential efflux inhibitor has been demonstrated. In this work, the chemical-physical properties of the SS13 were investigated; furthermore, a formulative study aimed to develop a formulation suitable for oral administration was performed. SS13 shows nonintrinsic antitubercular activity, but it increases the antitubercular activity of all the tested drugs on several strains. SS13 is insoluble in different simulated gastrointestinal media; thus, its oral absorption could be limited. Solid lipid nanoparticles (SLNs) were, therefore, developed by using two different lipids, Witepsol and/or Gelucire. Nanoparticles, having a particle size (range of 200-450 nm with regards to the formulation composition) suitable for intestinal absorption, are able to load SS13 and to improve its permeation through the intestinal mucosa compared to the pure compound. The cytotoxicity is influenced by the concentration of nanoparticles administered. These promising results support the potential application of these nanocarriers for increasing the oral permeation of SS13 in multidrug-resistant tuberculosis management.

Testing the absorption of the extracts of Coreopsis tinctoria Nutt. in the intestinal canal in rats using an Ussing chamber

ETHNOPHARMACOLOGICAL RELEVANCE

Coreopsis tinctoria Nutt mainly distributed in Hetian region of Xinjiang at an altitude of 3000m, which is used as Uyghur traditional medicine because of its clearing heat, promoting circulation and removing toxicity and antihypertension, ect. effect.

AIM OF THE STUDY

This research was to study the four ingredients in the extracts of Coreopsis tinctoria Nutt. that are absorbed in different intestinal segments in rats to lay the foundation for further study on the effective constituents, tissue distribution, metabolism, and spectrum-effect relationships of these extracts.

MATERIALS AND METHODS

High, medium, and low concentrations were prepared according to their pharmacological effects. Quantitative analysis multi-components by single marker was used to test the cumulative absorption volume Q, absorption rate constant Ka, and apparent permeability coefficient Papp of the four main ingredients in C. tinctoria Nutt. extract in different intestinal segments in rats using a Ussing chamber model and high-performance liquid chromatography.

RESULTS

The Papp of chlorogenic acid and flavanomarein in the duodenum, jejunum, ileum, and colon were 1.0×10(-6) to 10×10(-6)cms(-1). Papp of marein in the duodenum and jejunum was <1.0×10(-6), and was 1.0×10(-6) to 10×10(-6)cms(-1) in the ileum and colon. Papp of 3,5-O-dicaffeoylquinic acid in the duodenum was <1.0×10(-6)cms(-1), while it was 1.0×(1)0(-6) to 10×10(-6)cms(-1) in the jejunum, ileum, and colon.

CONCLUSIONS

All four chemical components of the plant extract can be absorbed by the intestinal canal of rats, which conforms to zero-order absorption; the ileum presented the best absorption.

Effect of permeability enhancers on paracellular permeability of acyclovir

Objectives

According to Biopharmaceutics Classification System (BCS), acyclovir is a class III (high solubility, low permeability) compound, and it is transported through paracellular route by passive diffusion. The aim of this study was to investigate the effect of various pharmaceutical excipients on the intestinal permeability of acyclovir.

Methods

The single-pass in-situ intestinal perfusion (SPIP) method was used to estimate the permeability values of acyclovir and metoprolol across different intestinal segments (jejunum, ileum and colon). Permeability coefficient (Peff) of acyclovir was determined in the absence and presence of a permeation enhancer such as dimethyl β-cyclodextrin (DM-β-CD), sodium lauryl sulfate (SLS), sodium caprate (Cap-Na) and chitosan chloride.

Key findings

All enhancers increased the permeability of paracellularly transported acyclovir. Although Cap-Na has the highest permeability-enhancing effect in all segments, permeation-enhancing effect of chitosan and SLS was only significant in ileum. On the other hand, DM-β-CD slightly decreased the permeability in all intestinal segments.

Conclusions

These findings have potential implication concerning the enhancement of absorption of paracellularly transported compounds with limited oral bioavailability. In the case of acyclovir, Cap-Na either alone or in combination with SLS or chitosan has the potential to improve its absorption and bioavailability and has yet to be explored.

Sulfobutylether-β-cyclodextrin/chitosan nanoparticles enhance the oral permeability and bioavailability of docetaxel

The aim of this research is to develop novel chitosan nanoparticles including cyclodextrins complexes for docetaxel (DTX), evaluate the performance of nanoparticles which could enhance the oral permeability and bioavailability of DTX in vitro and in vivo. DTX/sulfobutylether-β-cyclodextrin inclusion complexes were made and it was the main ingredient to prepare the DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles due to their promising physicochemical properties. DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles were prepared by the ionic gelation of chitosan with tripolyphosphate in the presence of cyclodextrins. Results indicated that DTX/sulfobutylether-β-cyclodextrin inclusion complexes and docetaxel/sulfobutylether-β-cyclodextrin/chitosan nanoparticles both had good performances in the studies of release and the rat small intestinal absorption in vitro. DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles showed preferable capability in improving the small intestinal absorption and inhibiting the efflux of DTX. In pharmacokinetics study, the DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles increased the AUC0→t and decreased the clearance significantly, and the oral relative bioavailability of the DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles was as high as 1447.53% compared to the pure DTX formulation. The DTX/sulfobutylether-β-cyclodextrin/chitosan nanoparticles prepared in this study have a good prospect for oral administration as an alternative of current DTX formulations.

Solid lipid nanoparticles with and without hydroxypropyl-β-cyclodextrin: a comparative study of nanoparticles designed for colonic drug delivery

New solid lipid nanoparticles (SLN), composed of Compritol ATO888 (C) and hydroxypropyl-β-cyclodextrin (HP), were developed in order to study a new colon-specific formulation for diclofenac sodium (D) delivery. The prepared batches differ from each other by the molecular ratio between HP and D and by the composition of the matrix. Nanoparticles composed of an exclusively lipid matrix and nanoparticles with an oligomeric and lipid matrix were compared in order to establish the effect of both components on the drug delivery tests performed. The SLN preparation method was based on the oil/water hot homogenization process. Emulsions produced were cooled at room temperature and lyophilized in order to obtain dried nanoparticles; possible damage to nanoparticle shape and size was avoided by the addition of cryoprotectants to the aqueous dispersion of nanoparticles before exsiccation. An in vitro toxicity study was performed using CaCo(2) cells to establish the safety of the prepared SLN. Data obtained showed that production method studied guarantees emulsions composed of nanosized drops which can be dried by lyophilization into SLN with a size range of 300-600 nm. In vitro and ex vivo tests demonstrated that dried SLN can be considered as colon delivery systems; however, the matrix composition as well as the presence of cryoprotectant on their surface influences the release and permeation rate of D. The in vitro toxicity studies indicated that the SLN are well tolerated.

Development of solid nanoparticles based on hydroxypropyl-β-cyclodextrin aimed for the colonic transmucosal delivery of diclofenac sodium

Objectives

Nanoparticles were designed for the oral administration and transmucosal colon delivery of drugs.

Methods

Preparation parameters were studied in order to develop solid pH-dependent drug-release nanoparticles, constituted by hydroxypropyl-β-cyclodextrin and/or Eudragit® L100 loaded with diclofenac sodium. Nanoemulsions were prepared by the emulsion-evaporation method using various homogenizers. Different preparative conditions were tested. The emulsions obtained were analysed in terms of size and then dried to obtain solid nanoparticles which were characterized in vitro (particle size, morphology, dissolution, solid state characterization). The effect of nanoparticles on drug permeation through synthetic membranes, colonic pig mucosa and Caco2 cell line were performed. Toxicity studies were carried out to assess the safety of the raw materials used and the nanosystems produced.

Key findings

Appropriate parameters to obtain nanoemulsions stable enough to be desiccated were determined: Panda NS100L was the most suitable homogenizer for the preparation; particle size ranged between 100 and 600 nm depending on the production method. Solid nanoparticles were obtained by an exsiccation process, which does not modify the mean size. pH-dependent drug-release nanoparticles were obtained. The nanoencapsulation process decreased the crystallinity of the drug. Materials and nanoparticles were highly biocompatible. Transmucosal delivery of drug is dependent on the polymer and the test employed: cyclodextrin improved drug permeation across colonic pig mucosa.

Conclusions

Formulations containing hydroxypropyl-β-cyclodextrin represent new colon-targeted nanoparticles for transmucosal delivery of drugs.

Effects of Cyclodextrins on Drug Delivery Through Biological Membranes

Cyclodextrins have proven themselves to be useful functional excipients. Cyclodextrin derivatives can be hydrophilic or relatively lipophilic based on their substitution and these properties can give insight into their ability to act as permeability enhancers. Lipophilic cyclodextrins such as the methylated derivatives are thought to increase drug flux by altering barrier properties of the membrane through component extraction or fluidization. The hydrophilic cyclodextrin family also modulate drug flux through membranes but via different mechanisms. The current effort seeks to provide various explanations for these observations based on interactions of hydrophilic cyclodextrins with the unstirred water layer that separates the bulk media from biological membranes such as the gastric mucosa, cornea and reproductive tract. Theories on the serial nature of resistances to drug flux are used to explain why hydrophilic cyclodextrins can enhance drug uptake in some situation (i.e., for lipophilic material) but not in others. In addition, the nature of secondary equilibria and competition between cyclodextrins and rheologically important biopolymers such as mucin are assessed to give a complete picture of the effect of these starch derivatives. This information can be useful not only in understanding the actions of cyclodextrin but also in expanding their application and uses.

Evaluation by Q-RTPCR of the efficacy of ribavirin complexed with beta-cyclodextrin against measles virus in a mouse encephalitis model

The objective of this work was to study the antiviral activity of ribavirin on measles encephalitis infection when using cyclodextrins as carriers. The use of cyclic oligosaccharides can promote the activity of many drugs and the benefit of the association of ribavirin with beta-cyclodextrin has already been demonstrated in vitro. Intracranial inoculation of the rodent adapted neurovirulent CAM/RB strain of measles virus induces encephalitis in CBA/ca mice. The antiviral activity of the complex ribavirin/beta-cyclodextrin at molar ratio 1:1 has been evaluated in vivo in the above encephalitis model. CBA/ca mice were treated with daily intraperitoneal injection of ribavirin (40 mg/kg) with or without beta-cyclodextrin. The viral load in the brain of mice was quantified by real-time Reverse transcription-Polymerase chain reaction. Treatment of mice by the complex ribavirin/beta-cyclodextrin (1:1) by intraperitoneal route decreases the viral load in the brain of 1.1 and 0.7 log(10) Eq copies x mL(-1) compared to distillated water and ribavirin treatment, respectively. At the same time, free ribavirin injection shows a negligible difference compared to treatment by distillated water.