Abstract
The effects of three binding agents, microcrystalline cellulose (MCC), hydroxypropyl cellulose (HPC) and polyvinylpolypyrrolidone (PVPP), as well as a physical mixture and a freeze-dried mixture of MCC and HPC (4 : 1), on the binding and disintegrating properties of acetaminophen (AAP) tablets prepared by direct compression were studied. Swveral physical properties of the powders and tablets were also studied. The order of binding ability of the binding agents evaluated from the cohesion was as follows : freeze-dried mixture ≒MCC≒ physical mixture>HPC>PVPP. The order of hardness of AAP tablets containing various concentrations of the binding agents was as follows : freeze-dried mixture>physical mixture>MCC>HPC>PVPP. The disintegration time of AAP tablets containing MCC was very long, while that of tables containing other binding agents was short. This is probably because crystalline regions of MCC bond strongly to each other in tablets, and this is related to the small amount of water intake and low swelling ratio of MCC. PVPP was shown to have a rather large pore volume and small cohesion, and this is presumably related to the good disintegrating properties of PVPP. The physical mixture and the freeze-dried mixture of MCC and HPC were excellent binding agents and disintegrators for tablets of drug powders with poor binding properties such as AAP.
