Noah Lotan

PEG-coated nanospheres from amphiphilic diblock and multiblock copolymers: Investigation of their drug encapsulation and release characteristics1

The development of long-circulating carriers capable of continuously delivering drugs intravenously provides a potential approach to achieve targeting of drugs to specific sites of action. In this research, polyethylene glycol (PEG)-coated nanospheres were prepared in a single step process using amphiphilic diblock and multiblock copolymers, and their drug encapsulation properties and release characteristics were investigated in vitro. The results obtained indicate that the parameters controlling drug release characteristics of these nanospheres are the chemical composition of their hydrophobic core (i.e. polyester or polyanhydride), as well as the molecular weight and surface density of their hydrophilic (i.e. PEG) chains.

Nanotechnology for biomaterials engineering: structural characterization of amphiphilic polymeric nanoparticles by 1H NMR spectroscopy

Nanoparticles composed of diblock poly(D,L-lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) or a branched, multiblock PLA-(PEG)3 were prepared by the single emulsion technique. Results of previous studies of these nanoparticles suggested that their structure is of the core-corona type with a polyester core and an outer PEG coating. In the present study, 1H NMR spectroscopy was utilized to provide direct evidence of the structure of these nanoparticles suspended in an aqueous environment. The results confirm the existence of the core-corona structure under these conditions, and show that the PEG moieties extend out from the nanoparticle core into the aqueous environment, and exhibit chain mobility similar to that of PEG in solution.