Lipid nanocapsules

Perrier, T., Saulnier, P., Fouchet, F., Lautram, N. and Benoit, J.P. (2010) Postinsertion into Lipid NanoCapsules (LNCs) from experimental aspects to mechanisms. International Journal of Pharmaceutics, 396, 204—209. 

Allard E, Passirani C, Garcion E, Pigeon P, Vessieres A, Jaouen G, Benoit JP (2008) Lipid nanocapsules loaded with an organometallic tamoxifen derivative as a novel drug-carrier system for experimental malignant gliomas. J Control Release 130 146-153... 

In another study, radiolabeled and fluorescent lipid nanocapsules were synthesized by using a phase inversion process that followed the formation of an o/w microemulsion containing triglycerides, lecithins, and a nonionic surfactant. Results of the experiment revealed that lipid nanocapsules were rapidly accumulated within cells through active and saturating mechanisms. Nanocapsules could bypass the endo-lysosomal compartment with only 10% of the cell-internalized fraction found in isolated lysosomes. When nanocapsules were loaded with paclitaxel, smallest lipid nano capsules (LNCs) also were found to trigger the best cell death activity. ... 

Paillard A, Hindre F, Vignes-Colombeix C, Benoit IP, and Garcion E. (2010). The importance of endo-lysosomal escape with lipid nanocapsules for drug subcellular bioavaUability. Biomaterials, 31, 7542-7554. 

DeMuth, P.C., Moon, J.J., Suh, H., Hammond, P.T., Irvine, D.J. Releasable layer-by-layer assembly of stabilized lipid nanocapsules on microneedles for enhanced transcutaneous vaccine delivery. ACS Nano 6, 8041-8051 (2012)... 

A particularly interesting feature is represented by 5-OH substituted flavonols such as quercetin (1) and morin (6, Fig. 5a). In these molecules, the 5-OH group is able to hamper ESIPT from the 3-OH to the carbonyl oxygen favouring internal conversion." These flavonols establish specific interactions with their microenvironment, e.g. upon binding to biomolecu-les"" " or when placed in specific microenvironments such as Sodium Dodecyl Sulfate (SDS) micelles" and in lipid nanocapsules. 

The formation of polyurethane nanoparticles from inverse nano-emulsions (W/O) has also been achieved. Interfacial polyaddition in inverse nano-emulsion is of special interest since this allows the encapsulation of hydrophilic active materials such as proteins or nucleic acids. Thus, taking advantage of the high reactivity of tolylene 2,4-diisocyanate with water molecules, polyurea lipid nanocapsules with aqueous cores obtained from W/O nano-emulsions and prepared by PIT method were designed. Polymer synthesis occurs by in situ interfacial polymerization after nano-emulsion formation. Volatile oils employed as the continuous phase were removed by evaporation and the nanocapsules were redispersed in water. These nanocapsules could be potentially used for encapsulation of both hydrophilic and lipophilic molecules simultaneously. 

Anton N, Saulnier P, Gaillard C, Porcher E, Vrignaud S, Benoit JP. Aqueous-core lipid nanocapsules for encapsulating fragile hydrophilic and/or lipophilic molecules. Langmuir 2009 25 11413-9. 

Bdduneau A, Saulnier P, Hindre F et al (2007) Design of targeted lipid nanocapsules by conjugation of whole antibodies and antibody Fab fragments. Biomaterials 28 4978-4990... 

Liposomes are closely related to nanocapsules in structural layout but consist of an aqueous core surrounded by a bilayer membrane composed of lipid molecules, such as phospholipids [28], as illustrated in Figure 2c. The drug can be located in the aqueous core or in the bilayer membrane. 

The procedure chosen for the preparation of lipid complexes of AmB was nanoprecipitation. This procedure has been developed in our laboratory for a number of years and can be applied to the formulation of a number of different colloidal systems liposomes, microemulsions, polymeric nanoparticles (nanospheres and nanocapsules), complexes, and pure drug particles (14-16). Briefly, the substances of interest are dissolved in a solvent A and this solution is poured into a nonsolvent B of the substance that is miscible with the solvent A. As the solvent diffuses, the dissolved material is stranded as small particles, typically 100 to 400 nm in diameter. The solvent is usually an alcohol, acetone, or tetrahydrofuran and the nonsolvent A is usually water or aqueous buffer, with or without a hydrophilic surfactant to improve colloid stability after formation. Solvent A can be removed by evaporation under vacuum, which can also be used to concentrate the suspension. The concentration of the substance of interest in the organic solvent and the proportions of the two solvents are the main parameters influencing the final size of the particles. For liposomes, this method is similar to the ethanol injection technique proposed by Batzii and Korn in 1973 (17), which is however limited to 40 mM of lipids in ethanol and 10% of ethanol in final aqueous suspension. 

Lalush, I., Bar, H., Zakaria, I., Eichler, S., Shimoni, E. (2005). Utilization of amylose-lipid complexes as molecular nanocapsules for conjugated linoleic acid. Biomacromolecules, 6, 121-130. 

Germain M, Grube S, Carriere V et al (2006) Composite nanocapsules lipid vesicles covered with several layers of crosslinked polyelectrolytes. Adv Mater 18 2868-2871... 

Biologicals Lipids, peptides, nucleic acids, polysaccharides, viruses Vesicles, nanotubes, rings, nanoparticles, nanocapsules, nanospheres... 

Large and small vesicles are more frequently studied as dispersed ensembles due to their ease of preparation and compatibility with solution phase analytical/physical methods. Lipid polymerization yields vesicles with enhanced stability to surfactants, organic solvents, dehydration, and heat [26]. Polymerization also alters membrane permeability to ions and molecules. These unique properties have spawned development of stable nanocapsules, bioreactors, and sensors. Many if not most of the liposomal architectures, methods to stabilize them, and technological applications discussed below have evolved from earlier pioneering work by many research groups. The reader is referred to previous key reviews [3,26,28]. 

Fig. 21 Scheme of nanocapsule formation. The template liposome with homogeneously distributed monomers is irradiated with UV light, resulting in the formation of a fortified liposome. After lipid removal, the 2D polymer network constitutes an intact hollow nanocapsule. Reprinted with permission from [112]. Copyright 2006, American Chemical Society... 

Nanosuspensions consist of the pure poorly water-soluble drug without any matrix material suspended in dispersion. It is sub-micron colloidal dispersion of pure particles of drug stabilized by surfactants. By formulating nanosuspensions, problems associated with the delivery of poorly water-soluble drugs and poorly water-soluble and lipid-soluble drugs can be solved. Nanosuspensions differ from nanoparticles, " which are polymeric colloidal carriers of drugs (nanospheres and nanocapsules), and from solid-lipid nanoparticles, which are lipidic carriers of drug. 

The preparation of nanoparticles by precipitation from an organic solution is well known from the preparation of polymeric nanocapsules and can also be used for the SLN production. The lipid, drug and the stabilizer(s) are dissolved in a water-miscible organic solvent (e.g. acetone, ethanol) or solvent mixture and this solution is dropped in the stirred aqueous phase that may contain a hydrophilic surfactant. Chen et al. firstly evaporated a part of the solvent mixture at elevated temperature before injection into the cooled aqueous phase under stirring. ... 

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