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Drug releasing characteristics of thermo‐ and pH‐sensitive interpenetrating polymer networks based on poly (N‐isopropylacrylamide)
Author(s) -
Lim Young Ho,
Kim Dukjoon,
Lee Doo Sung
Publication year - 1997
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(19970627)64:13<2647::aid-app18>3.0.co;2-w
Subject(s) - swelling , acrylic acid , polymer chemistry , poly(n isopropylacrylamide) , interpenetrating polymer network , lower critical solution temperature , polymer , copolymer , polyurethane , materials science , chemistry , drug carrier , chemical engineering , drug delivery , nanotechnology , composite material , engineering
Interpenetrating polymer networks (IPNs) of poly(N‐isopropylacrylamide)/polyurethane (PNIPAAm/PU) and poly(N‐isopropylacrylamide)/poly(acrylic acid) (PNIPAAm/PAA) were synthesized to investigate the swelling and drug releasing behavior. The presence of urethane network in PNIPAAm/PU IPNs improved the mechanical strength, but reduced the swelling and drug releasing rates because of its hydrophobic characteristics. The swelling transition temperatures of PNIPAAm gels were little affected by the incorporation of PU networks in IPN structures. The drug releasing process was analyzed with a simple exponential expression of time dependent fractional drug release. The swelling and drug releasing behavior of PNIPAAm/PAa IPNs was significantly affected by the variation of PAA compositions. The drug release process changed from anomalous to dual type via zero‐order mode with increasing PAA concentration due to the competitive swelling rates between PNIPAAm and PAA during release process. The releasing rate decreased in the buffer solution of pH 7.4, but increased in that of pH 5.0 with increasing PAA concentration at both 28 and 37°C because the swelling power of PAA in pH 5.0 was much less than that in pH 7.4. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2647–2655, 1997