Chem. Pharm. Bull., 51(11),1348-1349, November 2003

Communications to the Editor

Controlled Release of Vitamin E from Thermo-Responsive Polymeric Physico-Gel

Masato ISHIDA,^a Hideki SAKAI,^a,b Shinji SUGIHARA,^c Sadahito AOSHIMA,^c Shoko YOKOYAMA,^*,d and Masahiko ABE^a,b

^a Faculty of Science and Technology, Tokyo Universtiy of Science; 2641 Yamazaki, Noda, Chiba 278-8510, Japan: ^b Institute of Colloid and Interface Science, Tokyo University of Science; 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-0825, Japan: ^c Department of Macromolecular Science, Graduate School of Science, Osaka University; Toyonaka, Osaka 560-0043, Japan: and ^d School of Pharmaceutical Sciences, Kyushu University of Health and Welfare; 1714-1 Yoshino-cho, Nobeoka, Miyazaki 882-8508, Japan. * To whom correspondence should be addressed. e-mail: s.yokoyama@phoenix.ac.jp

Thermo-sensitive copolymer consists of poly(2-ethoxyethyl vinyl ether) and poly(hydroxyethyl vinyl ether) (EOVE200-HOVE400), whose sol-gel transition temperature was 20.5 °C, was synthesized and its applicability to a drug delivery system was examined. Vitamin E (VE) was enclosed in EOVE200-HOVE400 and the release of VE was measured by varying the temperature 10⇔30 °C. There was no release of VE from EOVE200-HOVE400 at 30 °C, while VE was released when the temperature was reduced to 10 °C.

Key words thermo-sensitive copolymer; drug delivery system; vitamin E; sol-gel transition; polymeric micelle