Nanoparticles exhibit a high reactivity and strong tendency towards agglomeration. In this study, aluminum oxide (alumina) nanoparticles were characterized by gas adsorption (BET), transmition electron microscopy (TEM) and photon correlation spectroscopy (PCS) techniques to assess the agglomeration of the particles. There is a good correlation between the BET and TEM measurements but PCS was larger in the mean and median size and with a degree of agglomerates being detected. Some agglomeration was evident, but most of the particles existed as discrete objects as observed in the (HR) TEM images which were in good agreement with the agglomeration factor.

Purpose: Agglomeration in suspension is a size enlargement method that facilitates operation of solid processing and preserves the solubilization properties of fine particles. A small quantity of binder liquid is added into a suspension of microparticles, directly in the stirred vessel where the precipitation or crystallization took place. This study deals with the evaluation of the effect of agitation time before and after addition of binder liquid on agglomerates properties in order to give some insights into the mechanism of the formation of the agglomerates.Methods: Carbamazepine is used as a model drug and isopropyl acetate is used as binder liquid. The agglomerates characterization includes the particle size, morphology and density.Results: The results showed that, by increasing the agitation time before addition of binder liquid, smaller agglomerates with less density and irregular forms composed of larger crystals were obtained. However, with increasing agitation time after addition of binder liquid the agglomerates size and density increases and morphology improves. Indeed, by continuing agitation along the course of agglomeration the properties of the particles change gradually but substantially.Conclusion: With optimized agitation time before and after addition of binder liquid, spherical and dense agglomerates can be obtained.

Objective (s): This study dealt with the wet agglomeration process in which a small quantity of binder liquid was added into a suspension of crystals, directly in the stirring vessel where the crystallization took place. The purpose of this investigation was evaluation of the effect of temperature on the agglomeration process in order to gain insight into the mechanism of the formation of the agglomerates.Materials and Methods: Carbamazepine was used as a model drug and water/ethanol and isopropyl acetate were used as crystallization system and binder liquid, respectively. The agglomeration of crystals was carried out at various temperatures and the agglomerates were characterized in terms of size, morphology, density and mechanical strength.Results: Evaluation of the agglomerates along the course of agglomeration shows that the properties of the particles change gradually but substantially. Higher temperature of the system during agglomeration process favors the formation of more regular agglomerates with mechanically stronger and denser structure; this can be explained by the promotion effect of temperature on the agglomeration process.Conclusion: With optimized wet agglomeration temperature, spherical, dense, and strong agglomerates can be obtained.