Preparation and application of chiral recognizable thermosensitive polymers and hydrogels consisting of N‐methacryloyl‐s‐phenylalanine methyl ester

Abstract

AbstractAmphiphilic random copolymers, poly(R‐HPMA‐co‐S‐PAM) and poly(HPMA‐co‐S‐PAM), were prepared by radical copolymerization of N‐methacryloyl‐(S)‐phenylalanine methyl ester (S‐PAM) and N‐[(R)‐2‐hydroxypropyl]methacrylamide (R‐HPMA) or N‐(2‐hydroxypropyl)methacrylamide (HPMA) with various molar ratios of R‐HPMA (or HPMA) (m) to S‐PAM (n). Either aqueous solution of poly(R‐HPMA‐co‐S‐PAM) with the molar ratio of m : n = 0.81 : 0.19 or poly(HPMA‐co‐S‐PAM) with the molar ratio of m : n = 0.79 : 0.21 exhibited the lower critical solution temperature (LCST) at 16°C. The LCST in the presence of (S)‐(−)‐phenylalanine (S‐Phe) shifted from 16 to 20°C and 18°C for poly(R‐HPMA‐co‐S‐PAM) and poly(HPMA‐co‐S‐PAM), respectively, whereas the LCST did not shift in the presence of (R)‐(+)‐phenylalanine (R‐Phe). Thermosensitive Gel(R‐HPMA‐co‐S‐PAM) and Gel(HPMA‐co‐S‐PAM) were also prepared from radical copolymerization of S‐PAM and R‐HPMA or HPMA in the presence of N,N′‐ethylenebisacrylamide (EBAAm) as a crosslinker. When the gels shrunk at 40°C, the release of dansyl‐(R)‐phenylalanine (Dans‐R‐Phe) from the gel in which loaded Dans‐R‐Phe occurred was more easily done than that of Dans‐S‐Phe from the gel that loaded Dans‐S‐Phe. Thus, these thermosensitive copolymers and gels were found to exhibit chiral recognition for phenylalanine derivatives. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 228–236, 2001