Paracellular drug absorption enhancement through tight junction modulation

Orally Administered Chitosan-Coated Polycaprolactone Nanoparticles Containing Curcumin Attenuate Metastatic Melanoma in the Lungs

The study was aimed to evaluate the effect of orally administered chitosan-coated nanoparticles containing curcumin on metastatic melanoma. Chitosan-coated nanoparticles containing curcumin were prepared, and their antimetastatic activity was investigated both in vitro and in vivo. Curcumin decreased cell viability and induced apoptosis of B16F10 melanoma cells. We observed that curcumin significantly decreased the expression of metalloproteinases, which are known to be associated with migration and proliferation of cancer cells. Importantly, treatment with chitosan-coated nanoparticles containing curcumin decreased pulmonary tumor formation in a murine model of experimental metastasis. Histological analyses confirmed the macroscopic results in which lungs of mice treated with curcumin-loaded chitosan-coated polycaprolactone nanoparticles had only a few small nodules and most of them were free of melanoma. Our findings indicate that nanoparticles coated with the mucoadhesive polymer chitosan containing curcumin may be a promising approach and/or intervention for the treatment of malignant melanoma.

Planar bioadhesive microdevices: a new technology for oral drug delivery

The oral route is the most convenient and least expensive route of drug administration. Yet, it is accompanied by many physiological barriers to drug uptake including low stomach pH, intestinal enzymes and transporters, mucosal barriers, and high intestinal fluid shear. While many drug delivery systems have been developed for oral drug administration, the physiological components of the gastro intestinal tract remain formidable barriers to drug uptake. Recently, microfabrication techniques have been applied to create micron-scale devices for oral drug delivery with a high degree of control over microdevice size, shape, chemical composition, drug release profile, and targeting ability. With precise control over device properties, microdevices can be fabricated with characteristics that provide increased adhesion for prolonged drug exposure, unidirectional release which serves to avoid luminal drug loss and enhance drug permeation, and protection of a drug payload from the harsh environment of the intestinal tract. Here we review the recent developments in microdevice technology and discuss the potential of these devices to overcome unsolved challenges in oral drug delivery.

Metallic oxide nanoparticle translocation across the human bronchial epithelial barrier

Inhalation is the most frequent route of unintentional exposure to nanoparticles (NPs). Our aim was to quantify the translocation of different metallic NPs across human bronchial epithelial cells and to determine the factors influencing this translocation. Calu-3 cells forming a tight epithelial barrier when grown on a porous membrane in a two compartment chamber were exposed to fluorescently labelled NPs to quantify the NP translocation. NP translocation and uptake by cells were also studied by confocal and transmission electron microscopy. Translocation was characterized according to NP size (16, 50, or 100 nm), surface charge (negative or positive SiO2), composition (SiO2 or TiO2), presence of proteins or phospholipids and in an inflammatory context. Our results showed that NPs can translocate through the Calu-3 monolayer whatever their composition (SiO2 or TiO2), but this translocation was increased for the smallest and negatively charged NPs. Translocation was not associated with an alteration of the integrity of the epithelial monolayer, suggesting a transcytosis of the internalized NPs. By modifying the NP corona, the ability of NPs to cross the epithelial barrier differed depending on their intrinsic properties, making positively charged NPs more prone to translocate. NP translocation can be amplified by using agents known to open tight junctions and to allow paracellular passage. NP translocation was also modulated when mimicking an inflammatory context frequently found in the lungs, altering the epithelial integrity and inducing transient tight junction opening. This in vitro evaluation of NP translocation could be extended to other inhaled NPs to predict their biodistribution.

Epithelial transport of noscapine across cell monolayer and influence of absorption enhancers on in vitro permeation and bioavailability: implications for intestinal absorption

The purpose of this study was to investigate the permeation of Noscapine (Nos) across the Caco-2 and Madin-Darby canine kidney (MDCK) cell monolayers and to evaluate the influence of absorption enhancers on in vitro and in vivo absorption of Nos. The bidirectional transport of Nos was studied in Caco-2 and MDCK cell monolayers at pH 5.0-7.8. The effect of 0.5% w/v chitosan (CH) or Captisol (CP) on Nos permeability was investigated at pH 5.0 and 5.8. The effect of 1-5% w/v of CP on oral bioavailability of Nos (150 mg/kg) was evaluated in Sprague-Dawley rats. The effective permeability coefficients (Peff) of Nos across Caco-2 and MDCK cell monolayers was found to be in the order of pH 5.0 > 5.8 > 6.8 > 7.8. The efflux ratios of Peff < 2 demonstrated that active efflux does not limit the absorption of Nos. The use of CH or CP have shown significant (***, p < 0.001) enhancement in Peff of Nos across cell monolayer compared with the control group. The CP (1-5% w/v) based Nos formulations resulted in significant (***, p < 0.001) increase in the bioavailability of Nos compared with Nos solution. The use of CP represents viable approach for enhancing the oral bioavailability of Nos and reducing the required dose.

Excipient foods: designing food matrices that improve the oral bioavailability of pharmaceuticals and nutraceuticals

The oral bioavailability of many lipophilic bioactive agents (pharmaceuticals and nutraceuticals) is limited due to various physicochemical and physiological processes. Excipient foods can be designed to improve the oral bioavailability of these bioactive agents.

Buccal delivery of metformin: TR146 cell culture model evaluating the use of bioadhesive chitosan discs for drug permeability enhancement

The oral cavity is considered an attractive site of drug administration. Metformin is currently, used in oral diabetes treatment. The aim of the current study was to study the feasibility of metformin, to permeate the buccal epithelium applying a bioadhesive and permeation enhancing drug delivery system. The in vitro TR146 cell culture model was used to study the effect of drug concentration (5-100mM) and the impact of a bioadhesive chitosan formulation (discs) and chitosan in solution (0-20mg/mL) acting as a permeation enhancer. The permeation of metformin occurred by passive diffusion via the paracellular pathway driven by the concentration gradient, yet with a possibility of increasing the metformin transport by using higher, donor concentrations. When using floating baskets, as a new application of the TR146 cell culture model, it was possible to observe a time-dependent effect of the bioadhesive metformin discs and, metformin permeation may be increased due to a combination of bioadhesion and permeation enhancement induced by chitosan, although the permeation enhancing effect of chitosan was not statistically significant. The limited apparent buccal permeability of metformin observed in vitro, suggest that in vivo absorption of therapeutic doses of metformin needs to take place as a combination of buccal and intestinal absorption as metformin therapy requires the use of high doses.

Strategies for enhanced peptide and protein delivery

Recent advances in the fields of molecular biology and biotechnology have allowed for the large-scale production and subsequent exploitation of the therapeutic potential of protein- and peptide-based drugs. The facilitation of delivery of this class of drugs must be tailored to meet the requirements and often the limitations dictated by the route of delivery chosen. The aim of this review is to comprehensively discuss several routes of drug delivery, detailing the uses and exploitation of each, from origins to present day approaches. Specific reference is made to the compatibility or incompatibility of each approach in the facilitation of the delivery of drugs of protein origin. Additionally, the physiological nature of the delivery route and the inherent physiological obstacles that must be considered when determining the most suitable approach to drug design and delivery enhancement are also addressed. Examples of novel protein-based drug designs and delivery methodologies that illustrate such enhancement strategies are explored.