title: Starch-free grewia gum matrices: Compaction, swelling, erosion and drug release behaviour.
abstract: Polysaccharides are suitable for application as hydrophilic matrices because of their ability to hydrate and swell upon contact with fluids, forming a gel layer which controls drug release. When extracted from plants, polysaccharides often contain significant quantities of starch that impacts upon their functional properties. This study aimed to evaluate differences in swelling, erosion and drug release from matrix tablets prepared from grewia gum (GG) and starch-free grewia gum (GDS) extracted from the stems of Grewia mollis. HPMC was used as a control polymer with theophylline as a model drug. Swelling, erosion, and in-vitro release were performed in deionized water, pH 1.2 and pH 6.8 media. The Vergnaud and Krosmeyer-Peppas model were used for swelling and drug release kinetics, respectively. However, linear regression technique was used to determine the erosion rate. GDS compacts were significantly harder than the native GG and HPMC compacts. GDS matrices exhibited the fastest erosion and drug release in deionised water and phosphate buffer compared with the GG and HPMC. At pH 1.2, GDS exhibited greater swelling than erosion, and drug release was similar to GG and HPMC. This highlights the potential of GDS as a matrix for controlled release similar to HPMC and GG at pH 1.2 but with a more rapid release at pH 6.8. GDS may have wider application in reinforcing compacts with relatively low mechanical strength.
authors.affiliation: Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK; Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmaceutical Science, University of Jos, PMB 2084, Jos 930001, Nigeria.
authors.forename: E I
authors.initials: EI
authors.lastname: Nep
authors.affiliation: Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
authors.forename: K
authors.initials: K
authors.lastname: Asare-Addo
authors.affiliation: Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
authors.forename: M U
authors.initials: MU
authors.lastname: Ghori
authors.affiliation: Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK.
authors.forename: B R
authors.initials: BR
authors.lastname: Conway
authors.affiliation: Department of Pharmacy, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK. Electronic address: a.m.smith@hud.ac.uk.
authors.forename: A M
authors.initials: AM
authors.lastname: Smith
mesh_terms: D002626:Chemistry, Pharmaceutical; D019245:Compressive Strength; D065546:Drug Liberation; D032382:Grewia; D010936:Plant Extracts / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D053149:Plant Gums / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D018547:Plant Stems; D013213:Starch / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D013607:Tablets
chemical_list: D010936:Plant Extracts; D053149:Plant Gums; D013607:Tablets; D013213:Starch
keywords: Grewia gum; HPMC K4M; Matrix tablets; Starch-free grewia gum; Theophylline