Effect of Different Binders' Temperature on the Granule Size and Shape

The objective of this study was to analyze the effect of temperature of different binders on the size distribution and shape of a bimodal wet granulation. An initial sample of anhydrous lactose and monohydrate lactose is forced through a sieve to separate in different size particles. The particle size of anhydrous lactose required is within ranges of 180 - 150ìm, and the particle size of monohydrate lactose required is within ranges of 180 -150ìm and 150 ? 88ìm. The binder was heated to obtain temperatures of 35°C and 50°C. The bimodal sample (50/50) absorbed the water from the added binder solution, which consisted either of a 3% solution of ethanol or pure distillated water. Four samples were withdrawn, one each two minutes for each set of experimental conditions. Four experiments were performed which consisted of a wet granulation with only water at two different temperatures and a wet granulation with a 3% solution of ethanol with two different temperatures. These samples were analyzed using a Vision method and SEM to investigate the size distribution and shape of the granulation. It seems that within the first two minutes, each one of the experiment obtained a similar behavior regarding to its size distribution. After the first two minutes the experiment performed with only water at 35°C showed a significantly large distribution of size compared to the other three experiments. The behavior of the other three experiments were very similar but overall it seems that with a solution of ethanol with increasing temperature we obtain a larger size distribution, but only with water we obtain an inverse behavior. Coalescence due to the collisions of small and large particles is observed in the samples of two minutes showing the control of the fast stage. Samples of experiments with only water show a more porosity surface than the ones with ethanol. This proves that the granulation performed with ethanol seems to be more uniform. Also a wet granulated sample with water obtains a more spherical shape while a wet granulated sample with ethanol obtains a more elongated shape. Some preliminary conclusions are: initially the granulations performed with ethanol solution need more than eight minutes to complete its process; the granulations performed with water obtain a more circular shape than the ones performed with ethanol solution; and that with a greater temperature the particles obtain a more circular shape which is convenient for the process of tablet making.