title: Evaluation of xanthan and highly substituted galactomannan from M. scabrella as a sustained release matrix.
abstract: A highly substituted galactomannan (G) from Mimosa scabrella Bentham (Man:Gal 1.1:1), isolated from the seeds of a Brazilian leguminous tree and xanthan (X), an exopolysaccharide secreted by Xanthomonas campestris (Keltrol), were evaluated as a hydrophilic matrix system (XG) for controlled release (CR) of diclofenac sodium (DS) in tablets and capsules. The performance of XG (2:1) matrices containing 50 mg (A) or 100 mg (B) of DS was compared with a commercial CR product of DS. The drug release studies were carried out using a dissolution apparatus (paddle method) with gradual increase of pH values, from pH 1.4, to pH 4.0 (after 1 h) and to pH 6.8 (after 2 h). The results suggested the potential of XG systems as release retarding materials, which released 78.6 and 35.1% of drug after 24 h for capsules (A) and tablets (A), respectively. Drug release decreased with the increase of amount of drug and it is dependent of dosage form. Analysis of release data indicate a rather zero-order drug release with the erosion mechanism playing a dominant role.
authors.affiliation: Núcleo de Investigações Químico Farmacêuticas, Curso de Farmácia, Universidade do Vale do Itajaí-UNIVALI, CP 360, CEP 88302-202 Itajaí (SC), Brazil.
authors.forename: F
authors.initials: F
authors.lastname: Ughini
authors.forename: I F
authors.initials: IF
authors.lastname: Andreazza
authors.forename: J L M S
authors.initials: JL
authors.lastname: Ganter
authors.forename: T M B
authors.initials: TM
authors.lastname: Bresolin
mesh_terms: D003692:Delayed-Action Preparations / Q000737:chemistry*; D004008:Diclofenac / Q000008:administration & dosage / Q000737:chemistry; D005690:Galactose / Q000031:analogs & derivatives; D006863:Hydrogen-Ion Concentration; D008351:Mannans / Q000737:chemistry*; D031298:Mimosa; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012639:Seeds; D012995:Solubility
chemical_list: D003692:Delayed-Action Preparations; D008351:Mannans; D011135:Polysaccharides, Bacterial; C012990:galactomannan; D004008:Diclofenac; C002563:xanthan gum; D005690:Galactose