title: Bioadhesive properties and rheology of polyether-modified poly(acrylic acid) hydrogels.
abstract: Transient rheological properties and mucoadhesion of hydrogels composed of poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO, or Pluronic) block copolymers and poly(acrylic acid) were explored. Nine Pluronic copolymers ranging in nominal molecular weight and PPO/PEO content were grafted to PAA through C-C bonds, with or without the use of divinyl cross-linker, ethylene glycol dimethacrylate (EGDMA). The hydrogel elasticity increased with the PPO content in the copolymers, as well as in the presence of EGDMA. Tensile tests were conducted to measure the fracture strength and the work of adhesion between the hydrogels and rat intestinal tissue. The fracture strength was proportional to the gel pseudoequilibrium modulus and depended on the nominal length of the PPO segments in the parent Pluronic copolymer. The work of mucoadhesion and gel cohesion declined with the loss angle measured in oscillatory shear experiments. The length of the PEO segments in Pluronic affected the work of adhesion. Applications of the Pluronic-PAA gels as vehicles in oral drug delivery are discussed. The longest Pluronic copolymers bonded to PAA resulted in copolymeric gels with strongest mucoadhesive properties.
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Lev
authors.initials: L
authors.lastname: Bromberg
authors.forename: Marina
authors.initials: M
authors.lastname: Temchenko
authors.forename: Valery
authors.initials: V
authors.lastname: Alakhov
authors.forename: T Alan
authors.initials: TA
authors.lastname: Hatton
mesh_terms: D000180:Acrylic Resins / Q000138:chemical synthesis / Q000737:chemistry*; D000268:Adhesiveness; D000818:Animals; D002152:Calorimetry, Differential Scanning; D020100:Hydrogels / Q000138:chemical synthesis / Q000737:chemistry*; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007422:Intestines / Q000502:physiology; D008297:Male; D008970:Molecular Weight; D009092:Mucous Membrane; D020442:Poloxamer / Q000138:chemical synthesis / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012212:Rheology; D013696:Temperature; D013718:Tensile Strength; D014014:Tissue Adhesives
chemical_list: D000180:Acrylic Resins; D020100:Hydrogels; D014014:Tissue Adhesives; D020442:Poloxamer; C006903:carbopol 940