title: Moulded cross-linked chitosan matrix systems for controlled drug release.
abstract: Matrix-type drug delivery systems were prepared by moulding and drying cross-linked chitosan gels in 24-well plates and they were evaluated in terms of their physical properties, drug content, surface morphology and swelling. Furthermore, the in vitro drug release profiles were subjected to kinetic modelling at two different pH values. In general, the moulded matrix systems showed statistically significantly slower drug release compared to immediate release tablets as measured by the mean dissolution time. Drug release from the moulded matrix systems prepared from chitosan cross-linked with tripolyphosphate was pH-dependent as can be seen from the release exponent value (n) of 0.75 at pH 5.8 (anomalous transport, erosion), while the n value was only 0.40 at pH 7.4 (Fickian diffusion). The matrix systems obtained from chitosan cross-linked with sodium lauryl sulphate showed higher swelling but mostly Fickian diffusional release (n?=?0.25 at pH 7.4, n?=?0.41 at pH 5.8).
authors.affiliation: Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa.
authors.forename: Clemence
authors.initials: C
authors.lastname: Tarirai
authors.forename: Gill M
authors.initials: GM
authors.lastname: Enslin
authors.forename: Jan H
authors.initials: JH
authors.lastname: Steenekamp
authors.forename: Josias H
authors.initials: JH
authors.lastname: Hamman
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D048271:Chitosan / Q000737:chemistry*; D003692:Delayed-Action Preparations; D005782:Gels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D004364:Pharmaceutical Preparations / Q000737:chemistry; D011122:Polyphosphates / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013607:Tablets
chemical_list: D003692:Delayed-Action Preparations; D005782:Gels; D004364:Pharmaceutical Preparations; D011122:Polyphosphates; D013607:Tablets; D012967:Sodium Dodecyl Sulfate; D048271:Chitosan; C005692:triphosphoric acid