title: Drug release from thermo-responsive self-assembled polymeric micelles composed of cholic acid and poly(N-isopropylacrylamide).
abstract: Cholic acid, conjugated with amine-terminated poly(N-isopropylacrylamide) (abbreviated as CA/ATPNIPAAm), was synthesized by a N, N'-dicyclohexyl carbodiimide (DCC)-mediated coupling reaction. Self-assembled CA/ATPNIPAAm micelles were prepared by a diafiltration method in aqueous media. The CA/ATPNIPAAm micelles exhibited a lower critical solution temperature (LCST) at 31.5 degrees C. Micelle sizes measured by photon correlation spectroscopy (PCS) were approximately 31.6+/-5.8 nm. The CA/ATPNIPAAm micelles were spherical and their thermal size transition was observed by transmission electron microscope (TEM). A fluorescence probe technique was used for determining the micelle formation behavior of CA/ATPNIPAAm in aqueous solutions using pyrene as a hydrophobic probe. The critical micelle concentration (CMC) was evaluated as 8.9 x 10(-2) g/L. A drug release study was performed using indomethacin (IN) as a hydrophobic model drug. The release kinetics of IN from the CA/ATPNIPAAm micelles revealed a thermo-sensitivity by the unique character of poly(N-isopropylacrylamide) i.e. the release rate was higher at 25 degrees C than at 37 degrees C.
authors.affiliation: College of Pharmacy, Chosun University, Kwangju, Korea.
authors.forename: I S
authors.initials: IS
authors.lastname: Kim
authors.forename: Y I
authors.initials: YI
authors.lastname: Jeong
authors.forename: Y H
authors.initials: YH
authors.lastname: Lee
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000180:Acrylic Resins; D019826:Cholic Acid / Q000008:administration & dosage* / Q000737:chemistry; D008823:Micelles; D012995:Solubility; D013696:Temperature; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D019826:Cholic Acid; D008823:Micelles; D000099166:Polyacrylamides