title: Acrylic polymers as thickening agents for tetraglycol cosolvent.
abstract: This article evaluated the thickening properties of two different Eudragits, L and RS, in tetraglycol cosolvent in order to obtain high viscosity systems characterized by controlled release properties. Tetraglycol was chosen for its ability to dissolve a wide range of water insoluble drugs, while Eudragit RS and L for their specific dissolution and permeability properties under physiological conditions. Study of the rheological properties was performed to characterize elastic and viscous properties of Eudragit/tetraglycol samples in function of frequency and temperature. For all systems, the results outlined a liquid like behavior, as observed for dilute polymer solutions. In fact the fitting of the log G'-log G'' versus frequency curves showed a good agreement with the Rouse or Zimm models. So despite the increase in viscosity, samples still behaved like liquid systems. After the addition of paracetamol the release characteristics were defined pointing out the great release control properties of both Eudragit L and RS, which showed different release kinetics depending on the pH of the environment. Semisolid Eudragits/tetraglycol systems can be considered as a new alterative for the sustained release of insoluble or poorly water-soluble drugs.
authors.affiliation: University of Camerino, Department of Chemical Sciences, via S. Agostino 1, 62032 Camerino, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Bonacucina
authors.forename: Giovanni F
authors.initials: GF
authors.lastname: Palmieri
mesh_terms: D000082:Acetaminophen / Q000737:chemistry; D000180:Acrylic Resins / Q000737:chemistry*; D003692:Delayed-Action Preparations; D005782:Gels; D007700:Kinetics; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry*; D012212:Rheology; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013696:Temperature; D014783:Viscosity
chemical_list: D000180:Acrylic Resins; D003692:Delayed-Action Preparations; D005782:Gels; D011108:Polymers; D011109:Polymethacrylic Acids; D012997:Solvents; C038300:methylmethacrylate-methacrylic acid copolymer; C050528:Eudragit RS; D000082:Acetaminophen; D011092:Polyethylene Glycols; C018557:glycofurol