Method and apparatus for dry granulation

Abstract

A dry-granulation method for producing a tablet comprising (a) pharmaceutical active ingredient in an amount 50-90% w/w and (b) one or more excipients in an amount 10-50% w/w including at least a binder which comprises (i) preparing granules from a powder comprising a binder, a pharmaceutically active ingredient and optionally one or more other excipients or pharmaceutical active ingredients by a process characterized in that a compaction force is applied to the powder to produce a compacted mass comprising a mixture of fine particles and granules and separating and removing fine particles and/or small granules from the granules by entraining the fine particles and/or small granules in a gas stream in which the compacted mass flows, wherein the direction of the flow of the gas stream has a component which is contrary to that of the direction of flow of the compacted mass, and collecting the accepted granules (ii) blending the accepted granules with other components of the tablet in granular or fine powder form wherein in step (ii) at least one other component of the tablet formulation is in granular form and is prepared from a powder comprising said other component by a process characterized in that a compaction force is applied to the powder to produce a compacted mass comprising a mixture of fine particles and granules and separating and removing fine particles and/or small granules from the granules by entraining the fine particles and/or small granules in a gas stream in which the compacted mass flows, wherein the direction of the flow of the gas stream has a component which is contrary to that of the direction of flow of the compacted mass; and (iii) compressing the resultant blend to form a tablet; with the proviso that the tablet does not comprise (a) paracetamol, maize starch and microcrystalline cellulose in a ratio of 60:20:20 w/w, (b) acebutolol HCl and starch in a ratio of 90:10 w/w, (c) sodium valproate, hypromellose and maize starch in a ratio of 90:5:5 w/w, (d) ketoprofen and maize starch in a ratio of 50:50 w/w or (e) metformin HCl, microcrystalline cellulose and maize starch in a ratio of 80:14:6 w/w.