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Cholesteryl moiety terminated amphiphilic polymethacrylates containing nucleic acid bases for drug delivery
Author(s) -
Shiraishi Kohei,
Sugiyama Minoru,
Okamura Yoji,
Sugiyama Kazuo
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.25445
Subject(s) - moiety , copolymer , polymer chemistry , chemistry , amphiphile , thymine , aqueous solution , polymer , stereochemistry , organic chemistry , dna , biochemistry
Poly[9‐(2‐methacryloyloxyethyl)adenine] and poly[1‐(2‐methacryloyloxyethyl)thymine] with one pendant cholesteryl moiety at the polymer end (PMEA‐Chol, PMET‐Chol) and with two pendant cholesteryl moieties at both polymer ends as terminal groups (PMEA‐2Chol, PMET‐2Chol) were prepared by radical polymerization of 9‐(2‐methacryloyl‐oxyethyl)adenine (MEA) and 1‐(2‐methacryloyloxyethyl)thymine (MET) initiated with 4,4′‐azobis[(3‐cholesteryl)‐ 4‐cyanopentanoate] in the presence of 2‐mercaptoethanol or thiocholesterol as chain transfer reagents, respectively. The copolymers [PNiPAAm‐ co ‐PMEA‐ n Chol ( n = 1,2)] composed of N ‐isopropylacrylamide (NiPAAm) and MEA were also prepared in a similar manner. The self‐organization of these polymers and copolymers was confirmed by a fluorescence measurement, and then their critical concentrations of micelle formation (CMC) were determined. The mixture of PMEA‐2Chol and cholesterol as a lipophilic drug model formed a lamella type of complex with an interplaner spacing of d = 35.3 Å. The hypochromism based on the formation of a 1 : 1 interaction of adenine and thymine moieties was found to appear in the mixed aqueous solution of PMEA‐Chol and PMET‐Chol. Complementary interactions were also confirmed in the system of PMET‐2Chol and adenosine as well as PMEA‐2Chol and uridine. Cis‐dichlorodiammine platinum(II) (CDDP) was bound to PNiPAAm‐ co ‐PMEA‐Chol through the adenine moiety by ligand substitution atoms of CDDP. The amount of CDDP loaded on the copolymer was found to be 0.143 g g −1 . © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3064–3075, 2007