Solid lipid nanoparticles stability

Siekmann, B. and Westesen, K. (1994) Melt-homogenized solid lipid nanoparticles stabilized by the nonionic surfactant tyloxapol. I. Preparation and particle size determination. Pharm. Pharmacol. Lett. 3, 194—197. 

Photon Correlation Spectroscopy Diameters of Dynasan 114, 116, and 118 Solid Lipid Nanoparticles Stabilized with Mixtures of Cholic Acid Sodium Salt (NaCh) and poloxamer 407 (5% Lipid, 0.5% Surfactant) to Assess the Influence of Different Surfactant Mixtures on the Enzymatic Degradation (Lipase/Colipase Assay) of Solid Lipid Nanoparticles... 

K Westesen, B Siekmann. Investigation of the gel formation of phospholipid-stabilized solid lipid nanoparticles. Int J Pharm 151(l) 35-45, 1997. 

Olbrich, C., Kayser, O., Muller, R.H., and Grubhofer, N., Solid lipid nanoparticles (SLN) as vaccine adjuvant study in sheep with a mycoplasma bovis antigen and stability testing, International Symposium of Controlled Release and Bioactive Material, 2000, 27, 293-294. 

Freitas, C. and Muller, R. H., Stability determination of solid lipid nanoparticles (SEN) in aqueous dispersion after addition of electrolyte. J. MicroencapsuL, 16, 59-71, 1999. Bunjes, H., Westesen, K. and Koch, M. H. J., Crystallization tendency and polymorphic transitions in triglyceride nanoparticles. Int. J. Pharm., 129, 159-73, 1996. Freitas, C. and Muller, R. H., Correlation between long-term stability of solid lipid nanoparticles (SLN) and crystallinity of the lipid phase. Eur. J. Pharm. Biopharm., 47, 125-32, 1999. 

Zimmermaim E. and Muller R.H., Electrolyte- and pH-stabilities of aqueous solid lipid nanoparticle (SEN) dispersions in artificial gastrointestinal media, Eur. J. Pham. Biopham., 52, 203, 2001. 

Solid-Lipid Nanoparticles SLNs have been used to deliver small molecules and macromolecules such as DNA and peptides. The in vitro and in vivo applications of SLNs are reviewed elsewhere [125,126]. The stability and oral bioavailability of insulin were enhanced when administered in wheat germ agglutinin-conjugated nanoparticles [127], A polyoxyethylene stearate coat on the SLN confers stealth properties [128],... 

Freitas, C., and Muller, R. H. (1999), Correlation between long-term stability of solid lipid nanoparticles (SLN) and crystallinity of the lipid phase, Eur. J. Pharm. Biopharm., 47(2), 125-132. 

Goppert, T. M., and Muller, R. H. (2003), Plasma protein adsorption of Tween 80-and Poloxamer 188-stabilized solid lipid nanoparticles, J. Drug Target., 11, 225-231. 

Oil and water [oil-in-water (0/W) or water-in-oil (W/0)] emulsions are utilized for the production of nanoparticle dispersions. The colloidal emulsions are stabilized by a film of surfactants and polymers, which interact with the oil and water phases to prevent aggregation and droplet growth. These microemulsions are typically used as templates for the production of nanoparticles and solid lipid nanoparticles (SLN). 

Schwarz, C., Freitas, C., Mehnert, W. and Muller, R.H. (1995) Sterilization and physical stability of drug-free and etomidate-loaded solid lipid nanoparticles. Proc. Int. Symp. Control. Rel. Bioct. Mater. 22, 766-767. 

Heiati, H., Tawashi, R. and Phillips, N.C. (1998) Drug retention and stability of solid lipid nanoparticles containing azidothymidine palmitate after autoclaving, storage and lyophilization. J. Microencapsulation 15, 173-184. 

Use as a template to fabricate nanoparticulate systems The inherent thermodynamic stability, large interfacial area and small droplet size of the microemulsions enable them to act as a template for facile synthesis of pharmaceutical nanoparticulates systems such as solid lipid nanoparticles [11] and nanosuspensions [12]. Additionally, microemulsions represent nanoreactors which can be tailored to fabricate pharmaceutical nanomaterials. 

Solid lipid nanoparticles (SLN) SLN combine the advantages of traditional particulate drag carriers, but simultaneously avoid some of their major disadvantages. Like polymeric particles, they provide a modification of the release profile due to the solid state of the particle matrix and chemical stabilization - that is, the protection of drags incorporated into the soHd... 

Alberts, B. et ah, Molekular Biologic derZelle, Isted., Wiley-VCH, Weinheim, 1986. Muller, R.H. et al.. Phagocytic uptake and cytotoxicity of solid lipid nanoparticles (SLN) sterically stabilized with poloxamine 908 and poloxamer 407, J. Drug Target., 4, 161, 1996. 

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. 

Apart from the already established formulations, researchers are trying to develop novel oil-based formulations to combat the poor solubility and bioavailablity of NCE. Shevachman et al. developed novel U-type microemulsions to improve the percutaneous permeability of diclofenac. Shah et al.2 2 used microwave heating for the preparation of solid lipid nanoparticles by microemulsion techniques, which resulted in improved particle characteristics. Ki et al. reported sustained-release liquid crystal of injectable leuprolide using sorbitan monooleate. Recently, various novel oil-based drug delivery technologies are reported, which includes tocol emulsions, solid lipid nanopar-ticles, nanosuspensions, Upid microbubbles, sterically stabilized phospholipid micelles, and environmentally responsive drug delivery systems for parenteral administration.25 259... 

Freitas, C. and Muller, R. H., Effect of light and temperature on zeta potential and physical stability in solid lipid nanoparticle (SLN ) dispersions, Int. J. Pharm., 168, 221-229 (1998). 

Figure 9.4. Cryo-TEM images and proposed interpretation of the colloidal structures of lipid nanoparticles with different lipid matrixes and stabilized with poloxamer 188. NEmu-10% MCT emulsion, SLN glyceryl behenate. NLC-1.0 and NLC-3.0 glyceryl behenate/MCT mixture 9 1 and 7 3 (w/w). Reprinted from J. Control. Rel., Vol. 95, K. Jores et ah, Investigations on the structure of solid lipid nanoparticles (SLN) and oil-loaded solid Upid nanoparticles by photon correlation spectroscopy, field-flow fractionation and transmission electron microscopy, 217-227. Copyright (2004), with permission from Elsevier.

Figure 9.8. Decrease of the ESR signal intensity with time of different lipid nanoparticles during the ascorbic acid reduction assay. The lipid nanoparticles were stabilized with poloxamer 188 and labeled with tem-pol benzoate. With kind permission form Springer of Sciencefic Business Media Pharm. Res., Physicochemical Investigations on Solid Lipid Nanoparticles and on Oil-Loaded Solid Lipid Nanoparticles A Nuclear Magnetic Resonance and Electron Spin Resonance Study, 20, 1274-1283, (2003), K. Jores, W. Mehnert and K. Mader.

Solid lipid nanoparticles have been studied intensively with respect to their physicochemical properties as well as their potential usefulness as carrier system. However, solid lipid nanoparticles are a very heterogeneous group of carrier systems and a broad variety of matrix lipids as well as stabilizers are used for the preparation of SLN formulations. 

In 2008 Shahgaldian et al. introduced a para-amino calix[4]arene with dodecyl groups at the lower rim (17), that self-assembles into positively charged solid lipid nanoparticles (SLNs) with DNA binding properties. These SLNs were used for the transfection of mammalian cells, which will be discussed later in Sect. 24.7.1. The amphiphilic calixarene was also used to form well-defined Langmuir monolayers at the air water interface with relatively high dynamic stability, presented in the following Sect. 24.3.2 [26],... 

Commercial sugar ester surfactants have also been shown to provide steric stabilization for solid lipid nanoparticles and, due to their nonionic headgroup, are stable in electrolyte solutions [117]. However, they were less effective as a stabilizer in the low-pH environment of artificial gastrointestinal fluids. 

Helgason T, Awad TS, Kristbergsson K, Decker EA, McClements DJ, Weiss J. 2009. Impact of surfactant properties on oxidative stability of 3-carotene encapsulated within solid lipid nanoparticles. J Agric Food Chem 57 8033-8040. 

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