title: Characterization of novel pH-sensitive polymeric micelles prepared by the self-assembly of amphiphilic block copolymer with poly-4-vinylpyridine block synthesized by mechanochemical solid-state polymerization.
abstract: We fabricated novel pH-sensitive polymeric micelles consisting of amphiphilic block copolymer containing pyridyl groups as side chains in the hydrophobic block. The number average particle diameter of the polymeric micelles at pH 7 was approximately 200 nm. A decrease in pH resulted in deformation of the polymeric micelles over a very narrow pH range (between pH 5.7 and 5.6). Interestingly, micellization and demicellization occurred reversibly in this narrow pH range. Polymeric micelles incorporating 5-fluorouracil (5FU) were also prepared. Decreasing the pH of this polymeric micelle solution from 7 to 5.5 resulted in the rapid release of 5FU at pH 5.6; the drug was completely released within 30 min. These results suggest that deformation of the polymeric micelles caused the rapid release of 5FU.
authors: Laboratory of Pharmaceutical Physical Chemistry, Gifu Pharmaceutical University, Japan.
authors: Shin-ichi
authors: S
authors: Kondo
authors: Keitarou
authors: K
authors: Yamamoto
authors: Yuka
authors: Y
authors: Sawama
authors: Yasushi
authors: Y
authors: Sasai
authors: Yukinori
authors: Y
authors: Yamauchi
authors: Masayuki
authors: M
authors: Kuzuya
mesh_terms: D004337:Drug Carriers / Q000737:chemistry; D005472:Fluorouracil / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D058105:Polymerization; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D008823:Micelles; D011108:Polymers; D011725:Pyridines; C029351:4-vinylpyridine; D005472:Fluorouracil