Polypropyleneimine dendrimers

Wang SJ, Brechbiel M, Wiener EC. Characteristics of a new MRI contrast agent prepared from polypropyleneimine dendrimers, generation 2. Invest Radiol 2003 38 662-668. 

Figure 13 Synthesis of a diphosphine G2 polypropyleneimine dendrimer by polymer-analogous modification [46],...

Dendrimeric Contrast Agents. A review has been prepared by Kobayashi and BrechbieF In recent work, Wang et al. report the Ti field dispersion profiles of a new Gd(III) contrast agent prepared from polypropyleneimine dendrimers, generation 2. Yordanov et al. have used Gd(III) dendrimers as biometric nanoprobes to detect vascular permeability. Francese et al. have characterized proton relaxivity of PAMAM dendrimers functionalized by nit-ronyl nitroxide radicals. 

Xu. Z. Ford. W.T. Polystyrene latexes containing poly-(polypropyleneimine) dendrimers. Macromolecules 2002, 35 (20). 7662-7668. 

Two components are needed to construct a dendrimer a multifunctional core and an ABx monomer unit around which to build up the structure. The most commonly used types are polyamidoamine dendrimers (PAMAM), poly 2,2-bis(methylol)propionic acid (PBisMPA) dendrimers, polybenzyl ether dendrimers (PBzE), polymelamine (triazine) dendrimers, polypropyleneimine dendrimers (PPI), and polylysine dendrimers (PEL). PAMAM, PPI and PBisMPA are commercially available. PAMAM (left), PBisMPA (middle) and PPI (right) in Figure 2.7 are the most commonly employed structures in therapeutic applications these have been well characterised both in vitro and in vivo, and their toxicological properties have been evaluated. 

Two different dendrimer families are presently commercially available Starburst polyamidoamine (PAMAM) dendrimers from Dendritech Inc., Midland, Michigan, and ASTRAMOL polypropyleneimine (PPI) dendrimers from DSM, Geleen, the Netherlands. 

Our group described a simple access to well-defined hyperbranched polyamines from hyperbranched PEI with different molecular weights, narrow molecular weight distributions, and an adjustable degree of branching [91]. According to this protocol fully branched analogs of polypropyleneimine (PPI) and polyamidoa-mine (PAMAM) dendrimers can be derived from hyperbranched PEI (Mw = 5,000, and 25,000 g mol-1) in a two-step synthetic process (Scheme 2). 

Dendrimers are hyperbranched polymers that emanate from a single core and ramify outward with each subsequent branching unit [1,2]. In the commonly employed divergent synthesis, dendrimers can be prepared through sequential, alternating reactions of two smaller units, one of which has a point of bifurcation. As is described elsewhere in this volume, several classes of dendrimers are known, including polypropyleneimine (PPI), polyamidoamine (PAMAM), and Frechet-type polyether dendrimers [1,2]. 

The treatment of collagen fibers with carbodiimides leads to an increase in viscosity. " Dendrimers, such as polypropyleneimine octaamine, are used in combination with EDC to crosslink collagen. " ... 

Following the first papers of Tomalia [178] and Newkome et al. [179] in 1985 dealing with dendrimers, a large number of dendrimers have been presented in the literature ranging from polyamidoamine, aromatic polyethers and polyesters, aliphatic polyethers and polyesters, polypropyleneimine, polyphenylene to polysilane. Copolymers of linear blocks with dendrimer segments (dendrons) and block copolymers of different dendrons have been described. 

These structures are accessible by a variety of techniques that include atom transfer radical polymerization (ATRP) methods and the use of living cationic polymerization. Tri-arm star structures are accessible by the living cationic growth of three chains from a triamino core structure and dendrimers have been obtained by the growth of structures based on a diaminobutane polypropyleneimine core with polyphosphazene outer branches. ... 

Chai et studied solvent induced chemical shifts for polypropyleneimine-16 dendrimer (89, containing 16 surface... 

---