DISSOLUTION AND SIMULATION CURVES FOR LOG-NORMAL PARTICLE-SIZE-DISTRIBUTED MODEL SYSTEMS

Log-normal particle-size-distributed systems were expressed as a generalized equation and the relative diameter which gave the maximum relative weight was expressed as a function of the standard deviation of log-normal particle-size distribution. Generalized distribution curves independent of the mean particle size were then obtained. Several mixed model systems were prepared with sieved n-propyl p-hydroxybenzoate crystalline particles following the generalized distribution curves. The dissolution of model systems were conducted under sink and nonsink conditions, and the dissolution processes were simulated on the basis of cube root law equations. After the validity of the simulation method was confirmed, the method was applied to estimate the apparent mean diameters which partially define the isotropic dissolution processes of log-normal particle-size-distributed systems. The apparent mean diameter was then expressed as a function of the standard deviation of log-normal particle-size distribution. © 1990, The Pharmaceutical Society of Japan. All rights reserved.