title: Influence of different polymer types on the overall release mechanism in hydrophilic matrix tablets.
abstract: The effect of three different types of polymer chain structures on the polymer release from hydrophilic matrix tablets was investigated by comparing a synthetic semi-crystalline linear polymer (PEO), a branched amorphous polysaccharide (dextran) and an amorphous substituted cellulose derivative (HPMC). The polymer release rates for tablets containing mixtures of high and low molecular weight grades in different ratios were determined by using a modified USP II method and a SEC-RI chromatography system. The results showed that independent of polymer type: (i) plots of the release versus time had similar shapes, (ii) the release of long and short polymer chains was equal and no fractionation occurred during the release and (iii) the release rate could be related to the average intrinsic viscosity of the polymer mixtures. This confirms the hypothesis that the release rate can be related to a constant viscosity on the surface of the hydrophilic matrix tablet and that it is valid for all the investigated polymers.
authors.affiliation: SCA Hygiene Products, SE-405 03 Göteborg, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Körner
authors.forename: Lennart
authors.initials: L
authors.lastname: Piculell
authors.forename: Frida
authors.initials: F
authors.lastname: Iselau
authors.forename: Bengt
authors.initials: B
authors.lastname: Wittgren
authors.forename: Anette
authors.initials: A
authors.lastname: Larsson
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D003911:Dextrans / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D065347:Hypromellose Derivatives; D008747:Methylcellulose / Q000031:analogs & derivatives / Q000737:chemistry; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D013607:Tablets / Q000737:chemistry*; D014783:Viscosity
chemical_list: D000180:Acrylic Resins; D003911:Dextrans; D004337:Drug Carriers; D011108:Polymers; D013607:Tablets; D065347:Hypromellose Derivatives; C006903:carbopol 940; D008747:Methylcellulose
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