Delivery barriers

Functions Required Within Polyplexes for Overcoming Delivery Barriers... 

STRATEGIES FOR OVERCOMING NASAL DELIVERY BARRIERS 19.4.1 Delivery Devices... 

Nishikawa, M., and L. Huang. 2001. Non-viral vectors in the new millennium delivery barriers in gene transfer. Hum. Gene. Ther. 12 861-870. 

To understand perfume behaviour on these surfaces and/or matrices, we must consider the range of attractive or repulsive forces between the perfume components and the surface itself. The situation is complicated by the way in which perfume is delivered to the surface. For example, for a perfume ingredient in a soap bar to be substantive it must first be efficiently delivered to the skin during washing, it must then survive rinsing and, finally, it must be retained for some time on the skin. Definitions of substantivity and of retention vary, but here retention is used to indicate the affinity a perfume has for a substrate when delivered to it, whilst substantivity also includes delivery barriers. 

Scheme 12 Nucleic acid nanoparticle formation and delivery barriers. Adapted and reprinted with permission from [95]. Copyright 2012 Elsevier...

Decreased cerebral blood flow, resulting from acute arterial occlusion, reduces oxygen and glucose delivery to brain tissue with subsequent lactic acid production, blood-brain barrier breakdown, inflammation, sodium and calcium pump dysfunction, glutamate release, intracellular calcium influx, free-radical generation, and finally membrane and nucleic acid breakdown and cell death. The degree of cerebral blood flow reduction following arterial occlusion is not uniform. Tissue at the... 

K. L. Audus and T. J. Raub, Biological Barriers to Protein Delivery, Plenum Press, New York, 1993. 

The predominance of the cationic species of DEC H" in membranes is consistent with the NMR spectra. If the neutral species are substantially increased in membranes, NMR signals of the neutral species can be observed in addition to the cationic species due to the difference in the delivery sites with a large barrier height in membranes. No independent NMR signals of the neutral species of DEC H" can be detected after the addition of the EPC SUV this indicates that the cationic species are dominant also in the hydrated membranes. 

Delivery systems for gene-based drugs are needed to fulfill their promise in the medical treatment. Interactions of the potential delivery systems with the lipid bilayers are of crucial importance, since the lipid bilayer barrier must be overcome either at the level of plasma membrane or in the endosomes. 

Interactions between Polymeric Drug Delivery Systems and Biological Systems Barriers and Opportunities... 

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