Physical properties of model viscoelastic materials.
Previous observations on polysaccharides used as viscoelastic agents in ophthalmic surgery suggest that the pseudoplasticity of solutions of hyaluronan (HA) and the low surface tension of hydroxypropylmethylcellulose (HPMC) solutions are physical properties that make these solutions useful clinically.  Our laboratories are interested in correlating the physical properties of macromolecular solutions with the ability of these molecules to protect ocular structures during eye surgery.  The purpose of this study is to compare the physical properties of model viscoelastics with the properties of HA and HPMC.  The results of these studies suggest that polysaccharides that form extended structures in solution at low shear rates and that are characterized by large decreases in the axial ratio at high shear rates, exhibit pseudoplastic behavior.  In this study pseudoplasticity is exhibited by polysaccharides with molecular weights in excess of 450 000, and is insensitive to the backbone chemistry for linear macromolecules.  In addition, low surface tension is associated with charged macromolecules that have a high positive second virial coefficient.
Department of Pathology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854.
F H
FH
Silver
J J
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LiBrizzi
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Benedetto
D001082:Aqueous Humor; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006801:Humans; D008422:Materials Testing; D008958:Models, Molecular; D011134:Polysaccharides / Q000737:chemistry*; D012542:Scattering, Radiation