title: Physicochemical properties of calcium polycarbophil, a water-absorbing polymer.
abstract: The physicochemical properties of calcium polycarbophil were examined. Calcium polycarbophil was decalcified rapidly under acidic conditions, affording polycarbophil. Polycarbophil absorbed about 10 times its own weight of water under acidic conditions, but the swelling ratio markedly increased at above pH 4.0 and reached 70 times the initial weight under neutral conditions. The swelling of polycarbophil was not affected by non-ionic osmolarity, but was affected by ionic strength, showing a decrease with increase of ionic strength. Monovalent metal ions such as sodium and potassium ions in gastrointestinal fluid did not reduce the equilibrium swelling of polycarbophil, but divalent ions such as calcium and magnesium ions did. However, calcium ion only slightly reduced the equilibrium swelling under sodium-rich conditions. The viscosity (as an indicator of fluidity) of polycarbophil was larger than that of CMC-Na at every shear rate and polymer content examined.
authors.affiliation: Research and Development Division, Hokuriku Seiyaku Co., Ltd, Katsuyama, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamada
authors.forename: M
authors.initials: M
authors.lastname: Kitayama
authors.forename: M
authors.initials: M
authors.lastname: Yamazaki
authors.forename: O
authors.initials: O
authors.lastname: Nagata
authors.forename: I
authors.initials: I
authors.lastname: Tamaj
authors.forename: A
authors.initials: A
authors.lastname: Tsuji
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000930:Antidiarrheals / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D002400:Cathartics / Q000737:chemistry*; D004337:Drug Carriers; D005782:Gels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration
chemical_list: D000180:Acrylic Resins; D000930:Antidiarrheals; D002400:Cathartics; D004337:Drug Carriers; D005782:Gels; C030312:calcium polycarbophil; D002118:Calcium