Synthesis And Characterization Of Polyester-dendrimer Systems From Glycerol, Glycolic Acid And Lactic Acid

Many anticancer drugs and other bioactive components with low molecular weight are limited in their therapeutic effect by properties such as low water solubility, poor bioavailability, and rapid elimination. In addition, while the beneficial effects of anticancer drugs arise through their interactions with tumor cells, undesirable side effects and toxicity typically result from their exposure to other cell types. Polymeric conjugates of drug have several advantages over their low molecular weight drugs. For example, the water solubility can be improved for low soluble or insoluble drugs and the circulation time of the polymer drug conjugate in the plasma can be increased through polymeric attachment. This enhancement in circulation time is the result of the decreased rate of renal filtration that correlates with molecular size, as molecules with larger hydrodynamic volume are generally eliminated more slowly. Since then, polymer-drug conjugates were seen as a means of preserving the drug's activity and decreasing the immunological body response. As well all of these had bring hope that most rational and effective utilization of anticancer drugs could become reality, and at the same time the toxic side effects of the anticancer drugs would be decreased obviously.Dendrimers, with well-defined molecular weight, are monodisperse globular polymers built from repetitive monomers with branching point units that are radially connected around a template core. So these macromolecules have been actively investigated for many applications including catalysis, molecular encapsulation, drug delivery, and so on. Dendrimer makes it possible to feed drug in nano-scale. However, the application of dendriemrs for drug delivery has been limited for its toxicity, poor degradability and biocompatibility.In this paper, we built dendrons based on glycerol, glycolic acid (GA) and lactic acid (LA). This dendron was biodegradble because of the ester bonds between those repeat units. They could form amphiphilic copolymer when conjugated with hydrophilic methoxy- polyethylene glycol (MPEG) which is useful in the field of drug delivery application.The research was mainly concerned with the following aspects:1. Synthesis and characterization of GA oligomer and GA-LA alternating oligomer; dendron base on glycerol and glycolic acid oligomer or glycolic acid-lactic acid oligomer; dendrimer from dendron with 4, 4′-diphenlymethane diisocyanate (MDI) as core.2. Synthesis and characterization of amphiphilic MPEG-dendron generation 3.3. Investigation of the micelle formed by amphiphilic MPEG-dendron generation 3.