Title: Compaction, compression and drug release characteristics of xanthan gum pellets of different compositions
Authors: Santos, Helton 
Veiga, Francisco 
Pina, M Eugénia 
Sousa, João José 
Keywords: Pellets;Extrusion-spheronisation;Xanthan gum;Compaction;Compression;Drug release;Diffusion;Erosion
Issue Date: 2004
Citation: European Journal of Pharmaceutical Sciences. 21:2-3 (2004) 271-281
Abstract: Compaction and compression of xanthan gum (XG) pellets were evaluated and drug release from tablets made of pellets was characterised. Three formulations were prepared by extrusion-spheronisation and included, among other excipients, diclofenac sodium (Dic Na), at 10% (w/w); xanthan gum, at 16% (w/w); and one of three different fillers (lactose monohydrated (LAC), tribasic calcium phosphate (TCP) and [beta]-cyclodextrin ([beta]-CD)), at 16% (w/w). Five hundred milligrams of pellets (fraction 1000-1400 [mu]m) were compacted in a single punch press at maximum punch pressure of 125 MPa using flat-faced punches (diameter of 1.00 cm). Physical properties of pellets and tablets were analysed. Dissolution was performed according to the USP paddle method. Pellets showed close compressibility degrees (49.27% LAC; 51.32% TCP; and 50.48% [beta]-CD) but densified differently (3.57% LAC; 14.84% TCP; 3.26% [beta]-CD). Permanent deformation and densification were the relevant mechanisms of compression. Fragmentation was regarded as non-existent. The release behaviour of tablets made of pellets comprising LAC or [beta]-CD was anomalous having diffusional exponent (n) values of 0.706 and 0.625, respectively. Drug diffusion and erosion were competing mechanisms of drug release from those tablets.
URI: http://hdl.handle.net/10316/5769
Rights: openAccess
Appears in Collections:FFUC- Artigos em Revistas Internacionais

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