Drug delivery to tumours using a novel 5-FU derivative encapsulated into lipid nanocapsules.

In this work, a novel lipophilic 5-fluorouracil (5-FU) derivative was synthesised and encapsulated into lipid nanocapsules (LNC). 5-FU was modified with lauric acid to give a lipophilic mono-lauroyl-derivative (5-FU-C12, MW of about 342 g/mol, yield of reaction 70%). 5-FU-C12 obtained was efficiently encapsulated into LNC (encapsulation efficiency above 90%) without altering the physico-chemical characteristics of LNC. The encapsulation of 5-FU-C12 led to an increased stability of the drug when in contact with plasma being the drug detectable until 3 h following incubation. Cytotoxicity assay carried out using MTS on 2D cell culture showed that 5-FU-C12-loaded LNC had an enhanced cytotoxic effect on glioma (9L) and human colorectal (HTC-116) cancer cell line in comparison with 5-FU or 5-FU-C12. Then, HCT-116 tumour spheroids were cultivated and the reduction of spheroid volume was measured following treatment with drug-loaded LNC and drugs alone. Similar reduction on spheroids volume was observed following the treatment with drug-loaded LNC, 5-FU-C12 and 5-FU alone, while blank LNC displayed a reduction in cell viability only at high concentration. Globally, our data suggest that the encapsulation increased the activity of the 5-FU-C12. However, in-depth evaluations of LNC permeability into spheroids are needed to disclose the potential of these nanosystems for cancer treatment.

Qualitative and Quantitative Study of the Potential of Lipid Nanocapsules of One Hundred Twenty Nanometers for the Topical Administration of Hydrophobic Molecules.

In this study, we evaluated the potential of lipid nanocapsules (LNC) of 120 nm as drug nanocarriers to treat skin diseases. As a model molecule, we encapsulated the fluorescent dye curcumin, which also is an antioxidant. Curcumin-loaded LNC showed interesting antioxidant properties and a low toxicity on human skin cells. The penetration of curcumin in the skin was determined by 2 complementary methods: high performance liquid chromatography was used to measure total curcumin accumulation in the skin, whereas fluorescence confocal spectral imaging of skin sections showed that curcumin preferentially accumulates in the stratum corneum and the viable epidermis. These results confirm that LNC of a size above 100 nm can vectorize hydrophobic compounds to the keratinocytes without transdermal delivery. They also demonstrate the interest of combining 2 analytical methods when studying the skin penetration of nanovectorized molecules.

Strategies for drug delivery to the human inner ear by multifunctional nanoparticles.

UNLABELLED: Hearing loss is a very significant health problem. The methods currently available for inner ear drug delivery are limited and a noninvasive cell-specific drug delivery strategy needs to be found. AIM: In this study we investigated the ability of polymersomes, lipid core nanocapsules and hyperbranched poly-L-lysine to cross the round window membrane. MATERIALS & METHODS: Nanoparticles (NPs) used in this study have different size and chemical compositions. Freshly frozen human temporal bones were used for this investigation. Intact human round window membrane within the freshly frozen human temporal bone served as an excellent model to test the membrane permeation and distribution within the tissues. RESULTS: In this investigation we were able to visualize the NPs across the round window membrane. The NPs were subsequently found to be distributed in the sensory hair cells, nerve fibers and to other cells of the cochlea. CONCLUSION: This finding raises hope in terms of future multifunctional NP-based drug delivery strategy to the human inner ear.

OPA quantification of amino groups at the surface of lipidic nanocapsules (LNCs) for ligand coupling improvement.

Lipidic NanoCapsules (LNCs) were prepared via an emulsion phase inversion method. Nanoparticles with hydrodynamic diameter of 25, 50 and 100 nm were easily obtained. Their surfaces are covered with short PEG chains (PEG 660) which are not bearing any chemical reactivities. Thus, in order to overcome this handicap towards post-functionalization possibilities, post-insertion of DSPE-PEG2000 amino (DSPA) can be employed. In order to characterize the insertion step, we have developed a chemical assay for the quantification of amino group inside the PEG shell of LNCs. Subsequently, the post-insertion yield was found to be comprised between 60 and 90% whatever the hydrodynamic diameter of the LNCs is. By means of simple calculations, the density of amino group is estimated to be closed to 0.2 and 1.2 molecules/nm(2). The formulation of LNCs and their controlled functionalization represent an interesting system for the development of bionanoconjugates in a short and effective process.

Inner ear biocompatibility of lipid nanocapsules after round window membrane application.

Nanoparticle-mediated drug delivery represents the future in terms of treating inner ear diseases. Lipid core nanocapsules (LNCs), 50 nm in size, were shown to pass though the round window membrane (RWM) and reached the spiral ganglion cells and nerve fibers, among other cell types in the inner ear. The present study aimed to evaluate the toxicity of the LNCs in vitro and in vivo, utilizing intact round window membrane delivery in rats. The primary cochlear cells and mouse fibroblast cells treated with LNCs displayed dosage dependant toxicity. In vivo study showed that administration of LNCs did not cause hearing loss, nanoparticle application-related cell death, or morphological changes in the inner ear, at up to 28 days of observation. The cochlear neural elements, such as synaptophysin, ribbon synapses, and S-100, were not affected by the administration of LNCs. However, expression of neurofilament-200 decreased in SGCs and in cochlear nerve in osseous spiral lamina canal after LNC delivery, a phenomenon that requires further investigation. LNCs are potential vectors for the delivery of drugs to the inner ear.

Methods for the functionalisation of nanoparticles: new insights and perspectives.

In the field of nanometre-sized drug-delivery systems, a wide range of colloidal systems have been created in recent decades. All of the systems have a similar global structure, that is, an inner part and an external surface/interface. In several applications, the external interface is the support for desired properties and the basis of future developments. The engineering of the particle's surface is an emerging step in the design of systems at the nanometre scale. This review presents and summarises the available techniques with a particular attention to recent advances. It is also a base for future works in this expanding area of research.

Post-insertion into Lipid NanoCapsules (LNCs): From experimental aspects to mechanisms.

Over the last decade, Lipid NanoCapsules (LNCs) have been intensively used as effective drug delivery systems; they are classically prepared using a phase-inversion method. Following formulation of the LNCs, the molecular insertion of commercially-available disteraoylphosphatidylethanolamine-peg amphiphiles is performed into the LNC shell, using a post-insertion method, more classically applied with liposomes. The subsequent LNC interfacial modifications are investigated by using size and electrokinetic measurements. More particularly, the length and the nature of the hydrophilic part of the post-inserted surfactant are modified. The results are discussed in order to improve our understanding of post-insertion mechanisms.

Potential novel drug carriers for inner ear treatment: hyperbranched polylysine and lipid nanocapsules.

AIM: Treatment of sensorineural hearing loss could be advanced using novel drug carriers such as hyperbranched polylysine (HBPL) or lipid nanocapsules (LNCs). This study examined HBPL and LNCs for their cellular uptake and possible toxicity in vitro and in vivo as the first step in developing novel nanosized multifunctional carriers. METHOD: Having incubated HBPL and LNCs with fibroblasts, nanoparticle uptake and cell viability were determined by confocal laser scanning microscopy, fluorescence measurements and neutral red staining. In vivo, electrophysiology, confocal laser scanning microscopy and cytocochleograms were performed for nanoparticle detection and also toxicity studies after intracochlear application. RESULTS: Both nanoparticles were detectable in the fibroblasts' cytoplasm without causing cytotoxic effects. After in vivo application they were visualized in cochlear cells, which did not lead to a change in hearing threshold or loss of hair cells. Biocompatibility and traceability were demonstrated for HBPL and LNCs. Thus, they comply with the basic requirements for drug carriers for potential application in the inner ear.

Distribution of lipid nanocapsules in different cochlear cell populations after round window membrane permeation.

Hearing loss is a major public health problem, and its treatment with traditional therapy strategies is often unsuccessful due to limited drug access deep in the temporal bone. Multifunctional nanoparticles that are targeted to specified cell populations, biodegradable, traceable in vivo, and equipped with controlled drug/gene release may resolve this problem. We developed lipid core nanocapsules (LNCs) with sizes below 50 nm. The aim of the present study is to evaluate the ability of the LNCs to pass through the round window membrane and reach inner ear targets. FITC was incorporated as a tag for the LNCs and Nile Red was encapsulated inside the oily core to assess the integrity of the LNCs. The capability of LNCs to pass through the round window membrane and the distribution of the LNCs inside the inner ear were evaluated in rats via confocal microscopy in combination with image analysis using ImageJ. After round window membrane administration, LNCs reached the spiral ganglion cells, nerve fibers, and spiral ligament fibrocytes within 30 min. The paracellular pathway was the main approach for LNC penetration of the round window membrane. LNCs can also reach the vestibule, middle ear mucosa, and the adjacent artery. Nuclear localization was detected in the spiral ganglion, though infrequently. These results suggest that LNCs are potential vectors for drug delivery into the spiral ganglion cells, nerve fibers, hair cells, and spiral ligament.

Phototransformation of stilbene in van der Waals nanocapsules.

We have utilized para-hexanoylcalix[4]arene nanocapsules as hosts to carry out phototransformations of cis- and trans-stilbene. Single-crystal X-ray diffraction studies were performed to define precisely the location of encapsulated stilbenes inside the capsule and to analyze possible pathways of phototransformation. cis-Stilbene stacks as a pi-pi dimer located at the center of the capsule, whereas trans-stilbene does not form such a dimer. Irradiation of the crystalline inclusion complexes of each isomer of stilbene in the solid state leads to the appearance of the second isomer, and after prolonged photolysis, photodimerization also occurs. syn-Tetraphenylcyclobutane is formed as the major product of dimerization and its yield depends on the time and intensity of irradiation. In most cases, the single crystals of the complexes remain intact during irradiation; hence, the nanocapsules have the potential to serve as robust nanoreactors in the solid state. The confinement in the nanocapsules is sufficient to keep the reacting molecules together, although this is less restrictive than for trans-stilbene crystals, in which the molecules cannot achieve a favorable orientation for dimerization.