Nanoparticle high-pressure homogenization

The techniques used for preparing nanoparticles are similar to those used to prepare more conventional drug particles and include controlled precipitation, ball milling using glass or zirconium oxide pearls, and high-pressure homogenization. 

Figure 6 The main broad avenues of nanoparticle production. Comminution or size reduction (say by high-pressure homogenization or critical solution technology), precipitation methods by salting out or other solvency changes in solutions of drag-polymers mixtures and molecular assembly of amphipathic components. Methods are listed in Table 2.

Silva A, Gonzalez-Mira E, Garcia M, Egea M, Fonseca J, Silva R et al. Preparation, characterization and biocompatibility studies on risperidone-loaded solid lipid nanoparticles (SEN) High pressure homogenization versus ultrasound. Colloids and Surfaces B Biointerfaces. 2011 86(1) 158-165. 

The bulk lipid mixtures and the corresponding nanoparticles were intensively studied by Schubert et al. using different methods (e.g. DSC, X-ray, NMR, electron microscopy) to get a deeper insight into the structure of this kind of lipid matrices. The lecithin was dissolved in the molten hard fat (Softisan 154) and colloidal dispersions were prepared after solidification of the lipid matrices by high-pressure homogenization. Solutol was added to the water phase for the stabilization of the nanoparticles. 

Exclusively submicron particles obtained by high pressure homogenization were used in a study which compared skin interaction of GMO-based cubic nanoparticles (with additional vesicular structures as observed by cryo-TEM) with that of other lipidic nanoparticles with compact liquid, crystalline or thermotropic liquid crystalline matrix structure. The cubic nanodispersion, which was stable with respect to particle size for 15 months of storage at room temperature, increased skin permeation of the model substance corticosterone (used in trace amounts in this study) compared to the other types of lipid nanoparticles. Permeation from all lipidic dispersions was, however, lower than from an aqueous solution which was attributed to the retention of a certain fraction of the drug in the lipid nanoparticles. Considering only the drug present in the aqueous phase of the dispersion as available for transport through the epidermis, the presence of cubic GMO particles increased permeation by the factor 2.4. 

Figure 2 Cross-section of an APV Micron LAB 40 high-pressure homogenizer. (Modified from MiiOer, R. -l, Gohlu. S.t Dingier, A. Schneppe, T.t Large scale produciion of solid lipid nanoparticles (SLhT ) and nanosuspensions (DissoCubes ), in flantibook of l harmaceMkah Controlled Release Technology. (Wise. D., cd.) in press).

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