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.
Bibliographical noteFunding Information:
We thank Dr. V. Torchilin and Dr. V. Trubetskoy (MGH-East, Dept. of Radiology, Charlestown, MA) for helpful discussion; Dr. D. Brown and J.M. Verbavatz (Massachusetts General Hospital-Harvard Medical School, Renal Unit, Charlestown, MA) for freeze-fracture studies; E.L. Shaw (MIT, Center for Materials Science and Engineering, Cambridge, MA) for ESCA studies; Robert J. Brown, Lillian T. Chong, Melissa M. Poh (MIT, Department of Chemical Engineering, Cambridge, MA) for technical assistance. This work was supported by NIH grant CA528557.