Improvement of sticking tendency of granules during tabletting process by pressure swing granulation

Abstract

A novel binderless coating method was developed to eliminate the sticking problem during tabletting process for the granules of a drug powder of high stickiness by using Pressure Swing Granulation (PSG) technique. PSG was applied to a mixture consisting of 70 wt.% milled lactose and 30 wt.% milled Ibuprofen (IBP) at an ambient temperature for the production of core granules and further coated with 2 wt.% fine lactose particles at 70 °C. These coated granules were compacted (at 199 MPa) in a tabletting machine to obtain tablets of 8 mm diameter. It was found that the coated layer of lactose particles on the granules was capable of blocking the migration of sublimated IBP during heating and coating. This was further verified experimentally by characterizing a one-dimensional system of an artificially coated granule (a lactose–IBP layer sandwiched in between two layers of lactose) using a microscope mapping technique of Raman spectroscopy. In a sample size of 200 tablets per batch, only 2% of the tablets were found to be sticking to the tabletting machine with the damaged area in the range of 1–10% of the total surface area of the tablet. Overall, PSG technique was found to be successful in eliminating sticking tendency of tablets during the tabletting process and the tablet hardness produced from the coated granules was found to be sufficiently strong enough to withstand handling and packaging process in the pharmaceutical industries.