pH-dependent mucoadhesion of a poly(N-isopropylacrylamide) copolymer reveals design rules for drug delivery.
This study investigated the mucoadhesive property of a hydrophobically modified copolymer N-isopropylacryamide and glycidylacrylamide NIPAM-N-Gly-(C18)2 (NIPAM-Gly). Prior studies demonstrated that the interfacial properties of this copolymer are pH dependent and that the chains form strong hydrogen bonds at pH < 7 via the carboxylic acid side chains of the glycine moieties. Mucin interactions with the copolymer brushes were investigated by surface plasmon resonance and by direct force measurements. Mucin adsorption was determined as a function of pH, ionic strength, and mucin concentration. It adsorbs to the copolymer strongly at pH 5, but the adsorption decreases with increasing pH. The adsorbed amount is also ionic-strength dependent, decreasing with increasing monovalent salt concentrations at all pH values investigated. When compared with similar investigations with poly(ethylene oxide), these results provide insights into both the chemical characteristics and the solution conditions that determine the mucoadhesive properties of polymers.
Zhu
X
X
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.
Degraaf
J
J
Winnik
F M
FM
Leckband
D
D
D000180:Acrylic Resins / Q000737:chemistry*; D000268:Adhesiveness; D000327:Adsorption; D000818:Animals; D002417:Cattle; D016503:Drug Delivery Systems; D015195:Drug Design; D005998:Glycine / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009077:Mucins / Q000737:chemistry; D009092:Mucous Membrane / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014014:Tissue Adhesives
D000180:Acrylic Resins; D009077:Mucins; D014014:Tissue Adhesives; C052970:poly-N-isopropylacrylamide; D005998:Glycine