Application of Melt Granulation Technology to Enhance Tabletting Properties of Poorly Compactible High-Dose Drugs

Using metformin HCl as the model drug and hydroxypropylcellulose (HPC) as the polymeric excipient, a melt granulation (MG) process that employs a twin-screw extruder has been developed to enhance compactibility of poorly compactible high-dose drug substances. A high (90%) drug-load tablet formulation, containing 1025 mg of active pharmaceutical ingredients and 109 mg of excipients, was produced. Drug-polymer-powder mixtures were melt granulated at a temperature above glass transition of HPC (130°C) but below melting point of metformin HCl (224°C). MG was compared with modified wet granulation (WG) and solvent granulation (SG) processes. Under identical compression force, the hardness of tablets produced was MG>SG>WG and the friability was MG