| 초록 |
Copolymers with hydrophilic blocks such as poly(ethylene glycol) (PEG) and hydrophobic blocks composed of biodegradable poly(amino acid) chain have potential utility as drug delivery system. Hydrophobic drugs can be physically loaded within polymeric micelles or chemically conjugated to poly(amino acid) with subsequent polymeric micelle formation. There are a few examples of water-soluble block copolymers that can self-assemble in pH-dependent manner. We were interested in poly(L-histidine), which is biodegradable polypeptide and thought to possess an amphoteric nature due to imidazole group of histidine. Particularly, the pKa of histidine is near physiological pH and this characteristic can be exploited to advantage for in vitro and in vivo uses. This property can be exploited to enhance the delivery of molecular pharmaceutical agents to tissues in which the pH drops below a critical pH. So, we designed the poly(L-histidine-co-phenyl alanine)-block-poly(ethylene glycol) copolymer and characterized its pH-dependent supramolecular self-assembly by 1H NMR, UV, MALDI-TOF, dynamic light scattering and fluorescence spectroscopy. |
