EFFECT OF SOME EXCIPIENTS AND COMPRESSION PRESSURE ON THE ADHESION OFAQUEOUS-BASED HYDROXYPROPYL METHYLCELLULOSE FILM COATINGS TO TABLET SURFACE

The adhesion between aqueous-based hydroxypropyl methylcellulose (HPMC ) films and tablet surface was evaluated using a Lloyd LRX materials t esting machine. Special attention was paid to the effects of compressi on pressure and the excipients (microcrystalline cellulose, lactose an d a commercial combination of lactose and cellulose (Cellactose(R))) o n the adhesion properties of the film. The adhesion of HPMC films was the lowest for the tablets containing lactose as a diluent and the hig hest for the tablets containing microcrystalline cellulose. The adhesi on to Cellactose(R)-based tablets increased with increasing compressio n pressure. With microcrystalline cellulose (MCC) and lactose, the eff ect of compression pressure on film adhesion was not so clear. The inc rease in concentration of a hydrophopic lubricant, magnesium stearate, decreased the adhesion between the films and tablets cores. The great est decrease was observed with the MCC tablets. Furthermore the result s showed that, the film coating increased clearly the mechanical stren gth of the tablets, depending on the excipient, the compression pressu re and amount of magnesium stearate.