title: Roller compaction of different pseudopolymorphic forms of theophylline: Effect on compressibility and tablet properties.
abstract: The effect of roller compaction on disintegration time, dissolution rate and compressibility of tablets prepared from theophylline anhydrate powder, theophylline anhydrate fine powder and theophylline monohydrate was studied. In addition, the influence of adding microcrystalline cellulose, a commonly used excipient, in mixtures with these materials was investigated. Theophylline anhydrate powder was used as a model drug to investigate the influence of different compaction pressures on the tablet properties. Tablets with same porosity were prepared by direct compaction and by roller compaction/re-compaction. Compressibility was characterized by Heckel and modified Heckel equations. Due to the property of polymorphic materials to change their form during milling and compression, X-ray diffraction analysis of theophylline anhydrate powder, theophylline anhydrate fine powder and theophylline monohydrate powders and granules was carried out. After roller compaction the disintegration time and the dissolution rate of the tablets were significantly improved. Compressibility of theophylline anhydrate powder and theophylline anhydrate fine powder was decreased, while theophylline monohydrate showed higher compressibility after roller compaction. Microcrystalline cellulose affected compressibility of theophylline anhydrate powder, theophylline anhydrate fine powder and theophylline monohydrate whereby the binary mixtures showed higher compressibility than the individual materials. X-ray diffraction analyses confirmed that there were no polymorphic/pseudopolymorphic changes after roller compaction.
authors.affiliation: Industrial Pharmacy Lab, Department of Pharmaceutical Sciences, University of Basel, Klingelbergstr. 50, 4056 Basel, Switzerland.
authors.forename: Ervina
authors.initials: E
authors.lastname: Hadzović
authors.forename: Gabriele
authors.initials: G
authors.lastname: Betz
authors.forename: Seherzada
authors.initials: S
authors.lastname: Hadzidedić
authors.forename: Silvia Kocova
authors.initials: SK
authors.lastname: El-Arini
authors.forename: Hans
authors.initials: H
authors.lastname: Leuenberger
mesh_terms: D002482:Cellulose / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D019245:Compressive Strength; D003460:Crystallization; D018360:Crystallography, X-Ray; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D010316:Particle Size; D016062:Porosity; D011208:Powders; D011312:Pressure; D012995:Solubility; D013499:Surface Properties; D013607:Tablets; D013678:Technology, Pharmaceutical / Q000379:methods*; D013806:Theophylline / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D011208:Powders; D013607:Tablets; D014867:Water; D002482:Cellulose; D013806:Theophylline; C109691:microcrystalline cellulose