title: Evaluation of the composition of the binder bridges in matrix granules prepared with a small-scale high-shear granulator.
abstract: The aim of this work was to evaluate the binder bridges which can form in hydrophilic matrix granules prepared with a small-scale high-shear granulator. Matrices contained hydroxypropyl methylcellulose (HPMC) as a matrix-forming agent, together with lactose monohydrate and microcrystalline cellulose as filler. Water was used as granulating liquid. A 2(4) full factorial design was used to evaluate the effects of the operational parameters (impeller speed, chopper speed, dosing speed and wet massing time) on the granulation process. The temperature of the sample increased relevantly during the preparation in the small-scale apparatus. The same setup induced different temperature increases for different amounts of powder. This alteration enhances the solubility of lactose and decreases that of HPMC, and thus the quantities of the dissolved components can vary. Accordingly, changes in composition of the binder bridge can occur. Since exact determination of the dissolution of these materials during granulation is difficult, the consequences of the changes in solubility were examined. Differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and X-ray diffraction (XRD) measurements were made to evaluate the films prepared from liquids with different ratios of soluble materials. The DSC and XRD measurements confirmed that the lactose lost its crystalline state in the film. The TMA tests revealed that increase of the quantity of lactose in the film decreased the glass transition temperature of the film; this may be attributed to the interaction of the additives. At a lactose content of 37.5%, a second glass transition appeared. This phenomenon may be indicative of a separate amorphous lactose phase.
authors.affiliation: Department of Pharmaceutical Technology, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
authors.forename: János
authors.initials: J
authors.lastname: Bajdik
authors.forename: Gabriella
authors.initials: G
authors.lastname: Baki
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Szent-Királlyi
authors.forename: Klaus
authors.initials: K
authors.lastname: Knop
authors.forename: Peter
authors.initials: P
authors.lastname: Kleinebudde
authors.forename: Klára
authors.initials: K
authors.lastname: Pintye-Hódi
mesh_terms: D002152:Calorimetry, Differential Scanning / Q000379:methods; D002482:Cellulose / Q000737:chemistry*; D004867:Equipment Design; D005898:Glass; D065347:Hypromellose Derivatives; D007785:Lactose / Q000737:chemistry*; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D010316:Particle Size; D044367:Phase Transition; D011208:Powders; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D011208:Powders; D014867:Water; D065347:Hypromellose Derivatives; D002482:Cellulose; D008747:Methylcellulose; D007785:Lactose; C109691:microcrystalline cellulose