A polymeric micelle MRI contrast agent with changeable relaxivity.
Polymeric micelles were formed from cationic polymers (polyallylamine or protamine) and anionic block copolymers (poly(ethylene glycol)-b-poly(aspartic acid) derivative) that bound Gd ions providing high contrasts in Magnetic Resonance Imaging (MRI) by shortening the T(1) longitudinal relaxation time of protons of water. The Gd-binding block copolymer alone showed high relaxivity (T(1)-shortening ability) values from 10 to 11 mol(-1) s(-1), while the polymeric micelles exhibited low relaxivity values from 2.1 to 3.6 mol(-1) s(-1). These findings point to the feasibility of a novel MRI contrast agent that selectively provides high contrasts at solid tumor sites owing to a dissociation of the micelle structures, while selective delivery to the tumor sites is achieved in the polymeric micelle form.
Nakamura
Emiko
E
Tokyo University of Science, Department of Pharmaceutics, 2641 Yamasaki, Noda, Chiba 278-8510, Japan.
Makino
Kimiko
K
Okano
Teruo
T
Yamamoto
Tatsuhiro
T
Yokoyama
Masayuki
M
D003287:Contrast Media / Q000008:administration & dosage* / Q000737:chemistry; D019786:Gadolinium DTPA / Q000008:administration & dosage* / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D008823:Micelles; D009369:Neoplasms / Q000175:diagnosis; D011108:Polymers / Q000008:administration & dosage*
D003287:Contrast Media; D008823:Micelles; D011108:Polymers; D019786:Gadolinium DTPA