Site-specific polymerization

Fig. 6. The schematic representation of surface patterning, site-specific polymerization, and site-specific immobilization of microparticles.

The patterned organosilane monolayers introducing organolsilane molecule with a polymerization initiating unit are useful as template surfaces for site-specific polymerization. Atom transfer radical polymerization (ATRP) unit was immobilized as a monolayer component. Since ATRP is one of the most successful methods for polymerizing a variety of monomers in a controlled fashion [44, 45], tailor-made surface topography is possible. Several reports have described the formation of polymer thin film by the radical polymerization from the immobilized ATRP initiator [46, 47],... 

A different approach of site-specific polymerization and thus immobilization of a biorecognition element was shown by several research groups by utilizing electropolymerization [74-76]. In combination with microelectrodes in microchannel systems, a site directed simple immobilization of the biorecognition element could be achieved. Patterns can also be created by... 

Site-specific polymerization Flexible macromer design (tunable properties)... 

Polymeric microparticles have been studied and developed for several years. Their contribution in the pharmacy field is of utmost importance in order to improve the efficiency of oral delivery of drugs. As drug carriers, polymer-based microparticles may avoid the early degradation of active molecules in undesirable sites of the gastrointestinal tract, mask unpleasant taste of drugs, reduce doses and side effects and improve bioavailability. Also, they allow the production of site-specific drug targeting, which consists of a suitable approach for the delivery of active molecules into desired tissues or cells in order to increase their efficiency. 

Finally, site-specific delivery also depends on the extent of competing processes in the biological system as well as the interaction of the drug itself with the biological system. Therefore successful design of polymeric drug delivery approaches requires a comprehensive appreciation of the pharmacology, pharmacokinetics, and pharmacodynamics involved. 

Domb, A. J., Ed. Polymeric Site-Specific Pharmacotherapy, John Wiley Sons, New York, 1994. 

Rolland, A., et al. 1993. Site-specific drug delivery to pilosebaceous structures using polymeric microspheres. Pharm Res 10 1738. 

Weiner, A.L. 1994. Polymeric drug delivery systems for the eye. In Polymeric site-specific pharmacotherapy, ed. A.J. Domb, 315-346. Chichester Wiley. 

Butterfield DA, Colvin J, Liu J, Wang J, Bachas L, Bhattacharrya D (2002) Anal Chim Acta 470 29 Electron paramagnetic resonance spin label titration a novel method to investigate random and site-specific immobilization of enzymes onto polymeric membranes with different properties... 

Using this technology, the preparation of the fifth tier, monoaldehyde dendrimer was reported.[102] Subsequently, living poly(methyl methacrylate) (PMMA, prepared by group transfer polymerization) was treated with the site-specific cascades. Polydispersi-ties determined for the copolymer were similar to those recorded for the living polymer when smaller dendrimers were used, whereas the use of larger dendrimers for copolymer formation leads to a dependence of polydispersity on the dendrimer. 

Byrd KE, Hamilton-Byrd EL (1994) In Domb AJ (ed), Polymeric site-specific pharmacotherapy. John Wiley 8c Sons, New York, pp 142-155... 

Similar considerations hold also for syndio-specific polymerization catalysts, for which the C -symmetric zirconocene complex shown in Figure 19 is a prototype. Here the two coordination sites have opposite chirality. The preferred orientation of the C(oc)-C((3) segment of the polymer chain and hence the preferred enantiofacial orientation of the inserting olefin will thus alternate with each consecutive insertion, by which the Zr-CH2(polymer) bond moves from one coordination site to the other. 

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