AN INVESTIGATION INTO THE USE OF CREEP VISCOMETRY FOR IN-VITRO CHARACTERIZATION OF THE RAFT FORMING PROPERTIES OF TABLETS CONTAINING ALGINIC ACID AND ANTACID COMPONENTS

The established methods for assessing the strength of rafts formed in- vitro by alginic acid/antacid containing formulations rely on the dete rmination of forces required to disrupt the raft structure. Creep visc ometry is proposed as an alternative,non-destructive means of investig ating the characteristic parameters of this type of product. Several c ommercial chewable tablet formulations were investigated using this te chnique. The instantaneous compliance and the Newtonian viscosity were calculated from the creep compliance curves obtained for these produc ts and were used as raft strength indicators. Differences found in the raft strength parameters of the different products were attributed to interactions between the formulation components. Additional studies c onducted on experimental batches established that such interactions co uld be estimated using this technique. It was concluded that creep vis cometry could be usefully employed in investigations of alginate rafts and,possibly,other oral dosage forms which rely on the formation of v isco-elastic structures to modify drug release properties.