2011 Volume 71 Issue 6 Pages 344-350
Tablets that consisted of various composition ratios of magnesium oxide, 4 kinds of excipients, and 3 kinds of disintegrants were made by the direct powder compression method with a rotary tableting machine. These tablets were preserved for one week in an environment of 40℃ and 75% relative humidity, and hardness was measured. Hardness decreased about 40% in the tablet in which magnesium oxide had not been mixed compared with the hardness before preservation. On the other hand, the hardness of tablet before preservation was maintained, and the decrease in hardness was small in the tablet in which the magnesium oxide was mixed. Moreover, the larger the blending quantity of magnesium oxide was, the smaller was the level of the hardness loss. It was suggested that this was because a part of the prescribed powder dissolved into the moisture absorbed by magnesium oxide during preservation, this solution formed a liquid bridge between particles, this liquid bridge dried and became a solid bridge after the preservation, and the hardness of the tablet increased in the tablet in which the magnesium oxide was mixed.
