title: Rheological characterization of cataplasm bases composed of cross-linked partially neutralized polyacrylate hydrogel.
abstract: Viscoelasticity is a useful parameter for characterizing the intrinsic properties of the cross-linked polyacrylate hydrogel used in cataplasm bases. The aim of this study was to investigate the effects of various formulation parameters on the rheological characteristics of polyacrylate hydrogel. The hydrogel layers were formed using a partially neutralized polyacrylate (Viscomate(™)), which contained acrylic acid and sodium acrylate in different copolymerization ratios, as the cross-linked gel framework. Dihydroxyaluminum aminoacetate (DAAA), which produces aluminum ions, was used as the cross-linking agent. Rheological analyses were performed using a "stress amplitude sweep" and a "frequency sweep". The results showed that greater amounts of acrylic acid in the structure of Viscomate as well as higher concentrations of DAAA and Viscomate led to an increase in the elastic modulus (G'). However, greater amounts of acrylic acid in the structure of Viscomate and higher concentrations of DAAA had an opposite on the viscous modulus (G″); this might be owing to higher steric hindrance. The results of this study can serve as guidelines for the optimization of formulations for cataplasms.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Key Laboratory of Smart Drug Delivery, Ministry of Education, Fudan University, 826 Zhangheng Road, Shanghai, 201203, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Hongqin
authors.initials: H
authors.lastname: Zhang
authors.forename: Dianyun
authors.initials: D
authors.lastname: An
authors.forename: Jian
authors.initials: J
authors.lastname: Yu
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Teng
authors.initials: T
authors.lastname: Shen
authors.forename: Jianxin
authors.initials: J
authors.lastname: Wang
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000287:Administration, Topical; D000536:Aluminum Hydroxide / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003432:Cross-Linking Reagents; D004304:Dosage Forms; D005998:Glycine / Q000031:analogs & derivatives / Q000737:chemistry; D006245:Hardness Tests; D020100:Hydrogels / Q000737:chemistry*; D012212:Rheology
chemical_list: D000180:Acrylic Resins; D003432:Cross-Linking Reagents; D004304:Dosage Forms; D020100:Hydrogels; C006903:carbopol 940; D000536:Aluminum Hydroxide; C007420:dihydroxyaluminum aminoacetate; D005998:Glycine