title: Encapsulation of the synthetic retinoids Am80 and LE540 into polymeric micelles and the retinoids' release control.
abstract: The objective of this study was to encapsulate two synthetic retinoids Am80 and LE540 into polymeric micelles and to control the retinoids' release rate in vitro. Highly efficient encapsulation yields of these retinoids were obtained for micelles forming from PEG-poly(benzyl aspartate) block copolymers in the wide range of the benzyl substitution degree. The in vitro release examination for LE540 indicated very stable encapsulation of this retinoid owing to its strongly hydrophobic nature. On the other hand, Am80 exhibited a rapid release in Dulbecco's phosphate buffer saline. An addition of a hydrophobic alkyl amine in the Am80-encapsulation process successfully led to significant retardation of the Am80 release rate. A mechanism of the retardation was considered an increase of Am80 hydrophobicity due to an ion-pairing with the alkyl amine. This paper is the first report on release control in the polymeric micelle carrier system through the ion-pairing between an encapsulated drug and an additive.
authors.affiliation: Yokoyama Project, Kanagawa Academy of Science and Technology, KSP East 404, Sakado 3-2-1, Takatsu-ku, Kawasaki, Kanagawa 213-0012, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Satoh
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Higuchi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kawakami
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Hashida
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kagechika
authors.forename: Koichi
authors.initials: K
authors.lastname: Shudo
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yokoyama
mesh_terms: D001224:Aspartic Acid / Q000138:chemical synthesis / Q000737:chemistry*; D001565:Benzoates / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000138:chemical synthesis / Q000737:chemistry*; D003984:Dibenzazepines / Q000737:chemistry*; D004123:Dimethylamines / Q000737:chemistry; D005079:Excipients / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008823:Micelles; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D012176:Retinoids / Q000737:chemistry*; D012995:Solubility; D013764:Tetrahydronaphthalenes / Q000737:chemistry*
chemical_list: D001565:Benzoates; D001704:Biopolymers; D003692:Delayed-Action Preparations; D003984:Dibenzazepines; D004123:Dimethylamines; D005079:Excipients; C104183:LE 540; D008823:Micelles; D012176:Retinoids; D013764:Tetrahydronaphthalenes; C416210:poly(ethylene oxide)-block-poly(beta-benzyl aspartate); C061133:tamibarotene; D001224:Aspartic Acid; D011092:Polyethylene Glycols