Functional PEG for Drug Delivery

Department of Materials Science and Technology, Tokyo University of Science, Noda, Japan 

Department of Materials Science and Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan 

There are several reports on the preparation of heterotelechelic PEG (12-14). Most of them, however, started from commercially available PEGs possessing hydroxyl groups at both ends. In particular, one of the hydroxyl groups at the PEG ends was converted to another functional group first then, the other hydroxyl group was converted to one of the 

Sugar ended heierotelecnelic PE3e Q llylL-M42.-O0CW 

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Fig. 8 Nanosystems that may function as simultaneous drug delivery and imaging agents for targeting T cells (a) liposomal systems, (b) solid biodegradable nanoparticulates, and (c) macro-molecular dendrimer complexes. PEG polyethylene glycol, Gd-DTPA gadolininum-diethylene triamine penta acetic acid. (Adapted from [48])...

As mentioned above, the preparation of nanogels by addition reactions of functional macromolecular precursors is mainly used for biomedical applications. Thus, the choice of synthetic precursors for microgel formation is restricted to biocompatible materials. Moreover, as most applications are in drug delivery, the molecular weight of the gel precursors should be below the threshold for renal clearance, a value that depends on the molecular architecture and chemical nature of the polymer but that is usually smaller than 30kDa, which is set as the limit for linear PEG [97], Polymers that are mostly used and thus presented in more detail here are PEG, poly(glycidol) (PG), and polyethylene imine) (PEI). 

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