Particulate carrier

A notable property of liposomes, which has not been appreciated enough, is the presence of water inside liposomes. This makes them an excellent delivery system for biotechnologically engineered proteins with tertiary and quanternary structures which are sensitive to irreversible damage induced by dehydration, as often occurs with alternative, particulate carrier systems. 

UK Patent Application No PCT/GB 99/02796, Particulate Carriers for Biocide Formulations . 

Various factors that influence the release of drugs from particulate carriers are listed in Table 10. Drugs can be released by diffusion or by surface erosion, disintegration, hydration, or breakdown (by a chemical or an enzymatic reaction) of the particles. The release of drugs from microspheres follows a biphasic pattern that is, an initial fast release followed by a slower... 

Soluble macromolecules of both natural and synthetic origin have been used as drug carriers. When compared with the particulate carriers, soluble macromolecules (a) encounter fewer barriers to their movement around the body and can enter into many organs by transport across capillary endothelium or in... 

Pharmaceutical Particulate Carriers Therapeutic Applications, edited by Alain Rolland... 

Therefore, no detailed discussion on the interaction of any liposomes with any particular cell type should be stated here. We refer to several recent publications for a study of interaction of DOPE CHEMS liposomes and COS-7 and HUVEC (109) and for a study on size-dependent uptake of particles into B16-F10 (72). The combination of flow cytometry and a microscopic method (e.g., spectral bio-imaging) turned out to be highly useful both to study the initial mode of internalization and to follow the intracellular fate of liposomes and other particulate carrier systems. 

Shown in Figure 1 are the principal schemes for micelle and liposome formation and loading with various reporter moieties that might be covalently or noncovalently incorporated into different compartments of these particulate carriers. Although micelles may be loaded with a contrast agent only into the core in the process of micelle assembly, liposomes may incorporate contrast agents in both the internal water compartment and the bilayer membrane. 

The importance of tobacco includes both those constituents in smoke that may interact with nicotine directly, as well as those that indirectly influence a smoker s perception and behaviors. For example, some tobacco smoke constituents may alter the site of absorption of nicotine, such as bronchodilators (e.g., cocoa, licorice), which allow deeper inhalation and subsequent deposition of constituents in more highly permeable areas of the respiratory tract. Likewise, product changes to alter or control particle size, or to provide particulate carriers for vapor-phase smoke constituents, also could facilitate changes at the site of absorption (Ingebrethsen 1993). This would also include the use of acids or bases to alter the form of nicotine and basicity of smoke. Again, a wide range of relevant findings is indicated by internal documents (Ferris Wayne et al. 2006 Keithly et al. 2005 Pankow 2001). 

Oechslein, C.R., Fricker, G., and Kissel, T., Nasal delivery of octreotide Absorption enhancement by particulate carrier systems, 7 t. J. Pharm., 139 25-32 (1996). 

The earliest and most widely studied particulate carriers for paramagnetic substances are the liposomes, either entrapping hydrophilic contrast agents within the internal aqueous phase, or incorporating lipophilic complexes in their phospholipidic bilayer membrane 100,101). 

Colonic Drug Absorption and Metabolism, edited by Peter R. Bieck Pharmaceutical Particulate Carriers Therapeutic Applications, edited by Alain Rolland... 

Tomlinson, E. (1987) Biological opportunities for site-sped c drug delivery using particulate carriers, Chap. 2, In Drug Delivery Carrier (P. Johnson and J. G Lloyd-Jones, eds.), pp. 32-66, Ellis Horwood, Chichester, England. 

Erosion refers to the dissolution and/or degradation of the polymer to soluble fragments and the progressive weight loss of the matrix. A thorough understanding of the erosion mechanism of particulate carriers is... 

This occurred because of the rapid phase transition and slower evaporation and formation of nonporous microspheres in presence of ethyl-acetate. DCM produced porous microspheres and hence showed initial burst release. Use of ethanol along with DCM further increased the initial burst because of the structure of microspheres and inhomogeneous drug distribution. This feature may be very useful during the design of sustained release particulate carriers for highly water-soluble drugs. 

D. Meisner, Liposomes as a pulmonary drug delivery system, Pharmaceutical Particulate Carriers, (A. Rolland, ed.), Marcel Dekker, New York, 1993, p. 31. 

D. J. A. Crommelin, G. Scherphof, and G. Storm, Active targeting with particulate carrier systems in the blood compartment, Adv. Drug Deliv. Rev. 17 49-60 (1995). 

Liposomal formulations are one of the most promising particulate carriers and have been used for several years for oral delivery of peptide drugs such as... 

The process of phagocytosis is of particular relevance when particulate delivery systems, such as microspheres, liposomes and other advanced delivery systems (described in Chapter 5), are used. Such particulate carriers are susceptible to MPS clearance. Sequestration by the MPS is useful in some cases, for example in the treatment of certain microbial diseases. However, if the drag is to be delivered to sites other than the MPS, it is highly undesirable. Therefore considerable research effort is being directed towards methods of avoiding MPS uptake of drag delivery systems. Strategies to both exploit and avoid MPS uptake are described in detail in Chapter 5 (see Section 5.1.4). 

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