Évaluation des nanocapsules lipidiques pour l'absorption orale à l'aide de la nouvelle technique quantitative FRET

Les nanocapsules lipidiques (LNC) bénéficient de leur capacité à augmenter la biodisponibilité orale des nombreux médicaments encapsulés, ce qui en fait des nanomédecines orales très prometteuses. Cependant, l'absorption orale des LNC intactes n'a pas encore été bien étudiée en raison de l'absence d'un outil approprié pour les quantifier. Par conséquent, cette thèse vise à caractériser l'absorption orale des LNC intactes in vitro et in vivo. Des LNC de différentes tailles (50 et 85 nm) et des modifications de surface (aucune, DSPE mPEG2000 et stéarylamine) ont été développées pour les tests tout au long de la thèse. Pour la première partie, un nouveau modèle de coculture in vitro de l'épithélium Caco 2 et de l'endothélium HMEC-1 (modèle Caco 2/HMEC-1) a été développé pour étudier le transport in vitro des particules des LNC à travers les membranes de type épithélium intestinal endothélium. Pour la deuxième partie, la nouvelle technique quantitative FRET (transfert d'énergie par résonance de Förster) a été développée pour l'analyse quantitative des LNC intactes dans le sang, le foie et les fèces. Ensuite, la pharmacocinétique des LNC intactes a été étudiée après l'administration IV à l'aide de FRET. Enfin, l'absorption orale in vivo des LNC intactes a été étudiée chez le rats à travers 1) la biodisponibilité orale, 2) la biodistribution dans la veine porte hépatique et au foie, et 3) les LNCs intactes restant dans les fèces. L'étude in vitro a révélé que les LNC intactes avaient un transport inférieur à 1 % sur le modèle Caco 2/HMEC-1. L'étude in vivo a révélé 0 % de biodisponibilité orale et 0 % de LNC intactes a été quantifié dans la veine porte hépatique, le foie et les fèces après 4 heures de gavage oral. Les résultats suggèrent que les LNCs intactes peuvent ne pas être absorbées par la voie GI.Lipid nanocapsules (LNCs) benefit from their ability to increase the oral bioavailability of the many encapsulated drugs, making them one of the promising oral nanomedicines. However, the oral absorption of the intact LNCs itself has not yet been well studied because of the lack of an appropriate tool. Hence, this thesis aims to characterize the oral absorption of intact LNCs in vitro and in vivo. LNCs with different sizes (50- and 85-nm) and surface modifications (none, DSPE-mPEG 2000, and stearylamine) were developed for the tests throughout the thesis. For the first part, the new in vitro coculture model of Caco-2 epithelium and HMEC-1 endothelium (Caco-2/HMEC-1 model) was developed to investigate the in vitro particle transport of LNCs across the epithelium endothelium membranes. For the second part, the new quantitative (Förster resonance energy transfer) FRET technique was developed for quantitative analysis of intact LNCs in blood, liver, and feces. Then, the pharmacokinetics of intact LNCs was studied after IV administration using FRET. Finally, in vivo oral absorption of intact LNCs was studied in rats by evaluating 1) the oral bioavailability, 2) the biodistribution to hepatic portal vein and liver, and 3) the remaining intact LNC in the feces. The in vitro study found that intact LNCs had <1% transportation across theCaco-2/HMEC-1 model. The in vivo study found 0% in vivo oral bioavailability and 0% of intact LNCs is quantified in the hepatic portal vein,liver, and feces after 4 hours of oral gavage. The evidence suggests that intact LNCs may not be absorbed via the GI route

FRET as the tool for in vivo nanomedicine tracking

International audienceAdvanced drug delivery system utilizing a nanocarrier is the major application of nanotechnology on pharmacotherapeutics. However, despite the promising benefits and a leading trend in pharmaceutical research, nanomedicine development suffers from a poor clinical translation problem as only a handful of nanomedicine products reach the market yearly. The conventional pharmacokinetic study generally focuses only on monitoring the level of a free drug but ignores the nanocarrier's role in pharmacokinetics. One hurdle is that it is difficult to directly track intact nanocarriers in vivo to explore their pharmacokinetics. Although several imaging techniques such as radiolabeling, nuclear imaging, fluorescence imaging, etc., have been developed over the past few years, currently, one method that can successfully track the intact nanocarriers in vivo directly is by Förster resonance energy transfer (FRET). This review summarizes the application of FRET as the in vivo nanoparticle tracker for studying the in vivo pharmacokinetics of the organic nanocarriers and gives elaborative details on the techniques utilized

Pharmacokinetics and oral absorption of different lipid nanocapsules: new quantitative FRET technique revealing PEGylation increasing the particle’s clearance

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Pharmacokinetics and oral absorption of different lipid nanocapsules: new quantitative FRET technique revealing PEGylation increasing the particle’s clearance

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Population pharmacokinetic modelling of intravenous LNCs FRET in rat

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Population pharmacokinetic modelling of intravenous LNCs FRET in rat

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New In Vitro Coculture Model for Evaluating Intestinal Absorption of Different Lipid Nanocapsules

International audienceStandard models used for evaluating the absorption of nanoparticles like Caco-2 ignore the presence of vascular endothelium, which is a part of the intestinal multi-layered barrier structure. Therefore, a coculture between the Caco-2 epithelium and HMEC-1 (Human Microvascular Endothelial Cell type 1) on a Transwell® insert has been developed. The model has been validated for (a) membrane morphology by transmission electron microscope (TEM); (b) ZO-1 and β-catenin expression by immunoassay; (c) membrane integrity by trans-epithelial electrical resistance (TEER) measurement; and (d) apparent permeability of drugs from different biopharmaceutical classification system (BCS) classes. Lipid nanocapsules (LNCs) were formulated with different sizes (55 and 85 nm) and surface modifications (DSPE-mPEG (2000) and stearylamine). Nanocapsule integrity and particle concentration were monitored using the Förster resonance energy transfer (FRET) technique. The result showed that surface modification by DSPE-mPEG (2000) increased the absorption of 55-nm LNCs in the coculture model but not in the Caco-2. Summarily, the coculture model was validated as a tool for evaluating the intestinal absorption of drugs and nanoparticles. The new coculture model has a different LNCs absorption mechanism suggesting the importance of intestinal endothelium and reveals that the surface modification of LNCs can modify the in vitro oral absorption

Green nanotechnology—An innovative pathway towards biocompatible and medically relevant gold nanoparticles

International audienceIn this review, we focus on recent advances in green nanotechnology, providing details on reliable synthetic pathways towards biocompatible and medically relevant gold and radioactive gold nanoparticles. We cover a wide plethora of synthetic protocols that utilize green nanotechnology with in-depth understanding of what makes a green process green. In section 2, we provide full details on the intervention of green nanotechnology for the production of various functionalized gold nanoparticles (AuNPs). Section 3 focuses on various characterization tools to be used for the complete physicochemical, size and in vitro characterization of gold nanoparticles before translating them into potential in vivo applications. Section 4 focuses on the science and applications of gold nanoparticles in diagnostic imaging. Specifically, we have highlighted the importance of the chemistry and physics of gold nanoparticles for applications in a myriad of diagnostic imaging including X-ray contrast agents, in single photon emission computed tomography (SPECT) imaging, positron-emission tomography (PET) imaging, optical coherence tomography (OCT), fluorescence imaging, magnetic resonance imaging (MRI), in surface enhanced Raman spectroscopy (SERS), and in ultrasound (US) imaging. Section 5 discusses latest advances on gold nanoparticles in drug delivery, gold nanoparticles in photothermal therapy and radioactive gold nanoparticles in cancer therapy. In particular, we discuss green nanotechnological interventions on how the electron rich phytochemicals including epigallocatechin gallate (EGCG) from tea, mangiferin (MGF) from mango and allied phytochemicals can be utilized in their dual roles, as reducing agents as well as rendering tumor specificity due to their strong tumor cell receptor avidity-to produce tumor specific molecular imaging and therapy agents. We also discuss latest advances on the importance of gold nanoparticles in X-ray Therapy. Important aspects relating to systemic toxicity of gold nanoparticles and ways to mitigate toxicity issues for their effective implementation in biomedical sciences are also discussed in section 6. The topics covered are intended to answer questions including why we should use green processes and what is the role of nanomedicine in the domain of human health and hygiene. Most importantly, we provide critical analysis on the ubiquitous role of gold nanoparticles in nanomedicine

Pharmacokinetics of intact lipid nanocapsules using new quantitative FRET technique

International audienceThe present study investigated the pharmacokinetics of intact lipid nanocapsules (LNCs) after intravenous administration in rats. Six different Förster resonance energy transfer LNCs (FRET-LNCs) have been studied with 2 sizes (50 and 85 nm) and 3 coating types (none, DSPE-mPEG 2000 or stearylamine). A FRET-LNCs blood extraction method was developed to retain an accurate FRET signal. Intact FRET-LNCs were specifically quantified through combination of FRET signal and Nano Tracker Analysis. Pharmacokinetic data were first described by non-compartmental analysis, then used to develop a population pharmacokinetic model. The pharmacokinetic elimination of FRET-LNCs was non-linear and dependent on size and surface modification, while the distribution was dependent on size. The LNCs 85 nm volume of distribution was lower than LNCs 50 nm. As expected, LNCs 85 nm with PEG coating displayed a lower clearance than other formulations. Surprisingly, this study highlighted a faster elimination of LNCs 50 nm with PEG compared to other formulations which could be explained by instability in blood. This first pharmacokinetic model of intact LNCs allowed a thorough understanding of the influence of size and coating on pharmacokinetic properties and paves the way for future mechanistic modeling approaches to predict the fate of LNCs in vivo