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Transport of ionizable drugs and proteins in crosslinked poly(acrylic acid) and poly(acrylic acid‐ co ‐2‐hydroxyethyl methacrylate) hydrogels. I. Polymer characterization
Author(s) -
Ende Mary Tanya Am,
Peppas Nikolaos A.
Publication year - 1996
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/(sici)1097-4628(19960124)59:4<673::aid-app13>3.0.co;2-r
Subject(s) - self healing hydrogels , acrylic acid , polymer chemistry , methacrylate , swelling , polymer , copolymer , polymerization , materials science , bioadhesive , (hydroxyethyl)methacrylate , chemical engineering , chemistry , composite material , engineering
The purpose of this investigation was to define the polymer structure and elucidate the swelling behavior of ionizable hydrophilic polymers (hydrogels) in water and buffered media. Poly(acrylic acid) (PAA) and poly(acrylic acid‐ co ‐2‐hydroxyethyl methacrylate) [P(AA‐ co ‐HEMA)] hydrogels were synthesized with varying degrees of hydrophilicity and crosslinking and were designed as potential bioadhesive controlled‐release dosage forms. The thermal initiation procedure employed during polymerization was optimized to eliminate unreacted residuals. Equilibrium and dynamic swelling studies were undertaken to determine the polymer mesh size and molecular weight between crosslinks of the hydrogels in the ionized and nonionized states. The PAA hydrogel mesh sizes ranged from 100 to 400 Å over pH values of 3–7, whereas the P(AA‐ co ‐HEMA) hydrogel mesh sizes were between 13 and 140 Å. These results demonstrated the significance of the swelling medium pH on the hydrated state of the polymers relative to crosslinking or copolymerization composition. © 1996 John Wiley & Sons, Inc.