Use of deacetylated gellan gum (Gelrite) for the production of sulphamethizole containing beads.

Deacetylated gellan gum (Gelrite) was used to produce a bead formulation containing sulphamethizole by a hot extrusion process into chilled ethylacetate. The spherical dried beads recovered had a porous surface which could be reduced in porosity by increasing the Gelrite concentration. Energy dispersive analysis showed the drug to be uniformly distributed throughout the beads. Dissolution studies confirmed that the drug was slowly released from the beads, the retardation of which could be extended by the use of increasing Gelrite concentration or by post-treatment of dried beads with either a waxy sealant or gamma irradiation. In-vivo studies in dogs confirmed that dried beads prepared by extruding a suspension of 10 per cent w/w sulphamethizole in 3 per cent aqueous Gelrite dispersion had effective sustained properties on oral dosing in comparison to a conventional capsule formulation but had a possible small loss in relative bioavailability.