抄録
The effects of different granulation methods on the anisotropy, the pore size and the crushing strength of tablets were studied. Calcium phosphate dibasic was granulated by three methods-(A) extruding granulation, (B) disintegrating granulation and (C) tumbling granulation. Five and 10% ethanol solutions of hydroxypropyl cellulose were used as binders. The degree of anisotropy of tablets was assessed in terms of the difference of the apparent compliance values between the compressive axial direction and the radial direction, which were obtained from the strain recovery at the ejection of tablets. The measurements of pore size in tablets were carried out with a mercury porosimeter. For both concentrations of the binder, the degree of anisotropy was in the order tablets (C) (tumbling granulation) > tablets (B) (disintegrating granulation) > tablets (A) (extruding granulation). It is presumed that the structure, bulk density and strength of the granules are important factors. At the same porosity, the mean pore diameters of the tablets were in the order tablets (C) > tablets (B) > tablets (A). The crushing strengths of the tablets were in the order tablets (A) > tablets (B) > tablets (C) for both concentrations of the binder. The larger the degree of anisotropy was, the larger the strain recovery was. Thus, it is presumed that large pores are formed by large strain recovery in the tablets, and consequently the strength of the tablets becomes low.
