title: Thermo-responsive self-assembled polymeric micelles for drug delivery in vitro.
abstract: Cholic acid (CA) was coupled with amine-terminated poly (N-isopropylacrylamide) (ATPNIPAAm) using N,N'-dicyclohexyl carbodiimide as a coupling agent. Self-assembled CA/PNIPAAm conjugate (abbreviated as CN) micelles were prepared by diafiltration method in water. The CN micelles exhibited the lower critical solution temperature (LCST) at 31.5 degrees C. The CN micelles were observed as spherical shapes and their dried sizes were ranged between 30 and 50 nm by the transmission electron microscope (TEM) images. Hydrated micelle sizes measured by photon correlation spectroscopy (PCS) were ranged 337.5+/-67.8 nm. And reversible size changes of CN micelles were observed with two point temperature 10 and 40 degrees C, respectively. From the fluorescence spectra, fluorescence intensity of pyrene in the CN micelles was increased and red-shifted as the concentration of CN increased, indicating the formation of self-assembled polymeric micelles in water. The critical micelle concentration (CMC) was evaluated as 8.9 x 10(-2) g/l. Much more indomethacin (IN) was released from th CN micelles at 10 than at 40 degrees C due to the thermo-sensitivity of the PNIPAAm in the CN polymer.
authors.affiliation: College of Pharmacy, Chosun University, #375 Seosuk-Dong, Dong-Gu, Kwangju 501-759, South Korea.
authors.forename: I S
authors.initials: IS
authors.lastname: Kim
authors.forename: Y I
authors.initials: YI
authors.lastname: Jeong
authors.forename: C S
authors.initials: CS
authors.lastname: Cho
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics; D019826:Cholic Acid / Q000737:chemistry / Q000493:pharmacokinetics; D016503:Drug Delivery Systems; D007213:Indomethacin / Q000493:pharmacokinetics; D008823:Micelles; D010316:Particle Size; D011108:Polymers / Q000737:chemistry / Q000493:pharmacokinetics*; D013696:Temperature
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D008823:Micelles; D011108:Polymers; D019826:Cholic Acid; D007213:Indomethacin