Site-specific release

Even though early success has been demonstrated with the use of polymers for peripheral and central nerve regeneration, it can be enhanced further by providing site-specific release of growth factors and other chemical cues to the regenerating axons, as described in the next section. 

In the design of drugs, the usefulness of renal-specific enzymes which enable the site-specific release of the active drug, should be taken into account. The design of kidney-selective prodrugs is based upon the relatively higher amounts of certain enzymes in the proximal tubular cells than elsewhere in the body. 

EXCIPIENTS USED IN SITE-SPECIFIC-RELEASE FORMULATIONS... 

Spectroscopic data obtained from spectroelectrochemical experiments require careful and case-specific analysis. The Fe /Fe redox couple has a unique role in diflferent iron-containing proteins. It is hypothesised that the mammalian iron-transport protein transferrin uses the Fe /Fe redox couple as a switch that controls the time and site-specific release of iron, while other iron-containing proteins, such as myoglobin, are able to hold on to iron in both oxidation states. Therefore, it is very important to evaluate the protein and its interaction with both the oxidised and reduced states of iron and accordingly develop a data-analysis model. The spectroelectrochemical response of an iron binding protein can be ideal Nernstian, non-Nernstian resulting from coupled... 

However, these advantages have been known for some decades (in fact an early publication on a site-specific release formulation of an insecticide dates back to 1948 (3)) but their exploitation has been slow to develop in commercial practice. The first microcapsule formulation came on the market in 1974 (4) since then, uptake represents only a small portion of total pesticide formulations. This is in contrast to the drug sector where controlled release and delivery has been rapidly expanding. 

PU-based drug delivery systems can be manipulated to have site-specific release (via cell targeting designs) and controllable drug release kinetics [128]. 

Beyond the option of carrying a drug or a biomolecule in the body, the site-specific release is also an important parameter towards the formulation of an appealing nanosystem, as it was discussed above for the intracellular release of... 

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