Homogenization, high-pressure

HPH has emerged as a reliable and powerful technique for the preparation of SLN. HPH has been used for years for the production of nanoemulsions for parenteral nutrition. In contrast to other techniques, scaling up represents no or minor problems in most cases. High-pressure homogenizers push a liquid with high pressure (10 to 

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Recovery. The principal purpose of recovery is to remove nonproteinaceous material from the enzyme preparation. Enzyme yields vary, sometimes exceeding 75%. Most industrial enzymes are secreted by a microorganism, and the first recovery step is often the removal of whole cells and other particulate matter (19) by centrifugation (20) or filtration (21). In the case of ceU-bound enzymes, the harvested cells can be used as is or dismpted by physical (eg, bead mills, high pressure homogenizer) and/or chemical (eg, solvent, detergent, lysozyme [9001 -63-2] or other lytic enzyme) techniques (22). Enzymes can be extracted from dismpted microbial cells, and ground animal (trypsin) or plant (papain) material by dilute salt solutions or aqueous two-phase systems (23). 

Talsma, H., Ozer, A. Y., van Bloois, L., and Crommelin, D. J. A. (1989). The size reduction of Uposomes with a high pressure homogenizer (Microfluidizer). Characterization of prepared dispersions and comparison of conventional methods. Drug Dev. Indust. Pharm.. 15, 197-207. 

High pressure homogenization may also be used to form microemulsions but the process of emulsification is generally inefficient (due to the dissipation of heat) and extremely limited as the water-oil-surfactant mixture may be highly viscous prior to microemulsion formation. ... 

D Souza, D. H., Su, X., Roach, A., and Harte, F. (2009). High-pressure homogenization for the inactivation of human enteric virus surrogates. /. Food Prot. 72, 2418-2422. 

Diels, A. M. J., Callewaert, L., Wuytack, E. Y., Masschalk, B., and Michiels, C. W. (2005). Inactivation of Escherichia coU by high-pressure homogenization is influenced by fluid viscosity but not by water activity and product composition. Int. ]. Food Microbiol. 101, 281-291. 

Pereda, J., Ferragut, V., Quevedo, J. M., Guamis, B., and Trujillo, A. J. (2007). Effects of ultra-high pressure homogenization on the microbiology and physicochemical shelf-life of milk. /. Dairy Sci. 90,1081-1093. 

Roach, A. and Harte, F. (2008). Disruption and sedimentation of casein micelles and casein micelle isolates under high-pressure homogenization. Innovative Food Sci. Emerg. Technol. 9,1-8. 

Due to particle sizes in the micrometer range, parenteral suspensions are generally limited to either subcutaneous or intramuscular routes of administration. However, ultrafine suspensions can be approached by high-pressure homogenization [200]. The particle size obtained from this technique is in the 100 500 nm range, thus intravenous administration is possible [201]. General information on parenteral formulations is given in Chapter 12. 

P Paquin. Technological properties of high pressure homogenizers the effect of fat globules, milk proteins and polysaccharides. Int Dairy J 9(3-6) 329-335, 1999. 

High pressure homogenizers are especially suitable for the emulsification processes in the food, pharmaceutical and bioprocess industries. A general disadvantage of these type of reactors is that there is no precise control over the cavitationally active volume and the magnitude of the pressure pulses that will be generated at the end of the cavitation events (cavitational intensity), unless the valve seat designs are substantially modified. 

Qian, C. and McClements, D.J. (2011) Formation of nanoemulsions stabilized by model food-grade emulsifiers using high-pressure homogenization factors affecting particle size. Food Hydrocolloids, 25 (5), 1000-1008. 

It has to be underlined that, in comparison to LS containing nucleic acid molecules inside the particle, the production of CLS may be performed obviously without considering the stability problems of nucleic acid molecules. In this view, some preparation procedures are not considered, such as the microemulsion technique [55] that represents a favorable method when working with substances unstable because of the high mechanical stress produced by high-pressure homogenization. 

Meuser, F. and German, H. 1984. Use of high-pressure homogenization for the production of starch from maize. Starch/Stdrke 36, 116-121. 

In the past, the majority of high-pressure homogeneous catalytic reactions were conducted in batch systems, which may cause problems in scale-up for SCFs because of the higher pressures needed for achieving the supercritical state. Therefore, continuous processing has also been investigated in the last years. It would be preferable for industrial-scale SCF reactions, because it involves smaller and, hence, safer equipment [144-150]. In addition, capital costs are likely to be lower than in batch systems. 

To reduee vesiele size and the number of bilayers, high pressure filtration via polyearbonate membranes as well as high pressure homogenization in a French press or in a mierofiuidizer are appropriate manufacturing procedures. Sonieation may also be applied, although the resulting dispersion does not have the same particle sizes. 

S. Mohan and G. Narsimham Coalescence of Protein-Stabilized Emulsions in a High-Pressure Homogenizer. J. Colloid Interface Sci. 192, 1 (1997). 

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