Effect of drug, formulation, and process variables on granulation and compaction characteristics of heterogeneous matrices .2. HPMC and PVP systems

A heterogeneous matrix comprising hydroxypropyl methylcellulose (HPMC) and polyvinylpyrrolidone (PVP) at various ratios was granulated using acetaminophen and pseudoephedrine as model drugs. The effect of drug, polymer ratio, total polymer loading, and volume of the granulating fluid on granule growth, granule size distribution, compaction, and tablet properties of the matrix was studied. Formulations containing both acetaminophen and pseudoephedrine required less water to granulate than those containing only acetaminophen. Moreover, the particle sizes of granules prepared with acetaminophen and pseudoephedrine were smaller than those containing only acetaminophen. Tablet hardness increased and friability decreased considerably in all formulations containing pseudoephedrine. In general, the tablet hardness and tablet disintegration time varied with changes in total polymer loading, fraction of HPMC in the matrix, and composition of the model drug(s). All the matrix systems studied showed good flow characteristics at different polymer loadings or HPMC-PVP ratio for matrices formulated with either acetaminophen or both acetaminophen and pseudoephedrine. The results of this study indicate that the presence of drug and/or other excipient(s) in the formulation affects the hydration characteristics of the matrix polymer(s) and compression properties of the granules.