Akinobu Otsuka

Influence of Punch Velocity on the Compressibility of Granules

AbstractThe influence of punch velocity over the range 1-30 mm/min on the compressibility of granules and particles was studied using a modified Kawakita equation. Granule strength (St) increased with increasing concentration and viscosity of binder solution as well as increasing mean molecular weight of binding agent. The compressibility of powders was evaluated by the modified Kawakita equation (K). For the granules, the relationship between pressure and reciprocal of porosity (I/e) showed an inflection point, but for the particles, no such inflection point was found. The slope of low compression stress in the stage of densification by powder slippage and rearrangement was the constant K1; and slope of high compression stress in the stage of elastic, plastic deformation and plastic fracture of particles was the constant K2. The K1 values decreased with increasing punch velocity. An approximately linear relationship was observed between reciprocal of compressibility constant (I/K2) and granule strength (...

Computer simulation of agglomeration by a two-dimensional random addition model — agglomeration kinetics and micromeritic properties of agglomerate accompanied by compaction process

Abstract In order to elucidate the mechanism of the compaction process of wet spherical agglomeration, computer simulation of agglomeration with compaction was carried out using a random addition model. The agglomeration process simulated by this model was described by a non-random coalescence agglome- ration and the compaction process of agglomerate was represented by the modified Kawakitas equation.

Agglomeration kinetics of monodisperse systems — computer simulation of agglomeration by a two-dimensional random walk model

Abstract Computer simulation has been used to elucidate agglomeration processes of monodisperse systems. It is shown that for processes where agglomeration occurs as a function of (a) particle encounter and (b) adherence probability, a relation results which is akin to Smoluchowski kinetics.

Application of Laser Hologram Interferometry to the Distortion Determination of Sugar-Coated Tablets

AbstractSugar-Coated tablets of different core materials were prepared and the degree of distortion of the sugar coat was determined by the laser holographic interferometry of double exposure method. It was found that, as the degree of expansion of the tablet core material increased, the sugar coat became more distorted. By the present method, nondestructive measurement of a minute amount of distortion is possible and thus superior to conventional methods.

Dissolution of Solid Dosage Form. III. Equations for the Dissolution of a Nondisintegrating Single Component Tablet under a Nonsink Condition

As equation was derived for the dissolution from the whole surface of a nondisintegrating single component tablet under a nonsink condition where the initial weight of a tablet is equal to the weight needed to saturate the solution. also, equations for several dissolution manners of the tablet under the nonsink condition were derived in the postulation of a dominant dissolution rate constant which determines the dissolution manner. The aplicability of these equations was examined by dissolution measurements with nondisintegrating single component tablets. Dissolution measurements of tablets prepared using the amount required to saturate the solution were conducted by masking their flat or side surface with adhesive tape in accordance with the conditions for the derivation of equations. These dissolution behaviors were treated by the use of derived equations to confirm the validity.Among the derived equations, dissolution from the whole surface of a tablet was expressed in the same form as the negative two-thirds law equation for particles, and a nondisintegrating single component tablet compressed by the use of stuitable amount was thought to behave like a single crystal. Also, equations, i.e., the negative two-thirds law and the negative square root law, thus derived were thought to be applicable for the dissolution of a nonspherical particle and crystal concerning the crystals habit and its dissolution property.