Preparation of Essential Oils Loaded Granule by Melt Granulation

Abstract

A comparative study on three granulation methods; melt granulation, fluidized bed granulation and wet granulation was performed to fabricate an essential oils loaded granule. The granule properties such as particle size distribution and the loading efficiency of anethole from fennel and cinnamaldehyde from cinnamon showed that the melt granulation in a high shear mixer was the most feasible method among the three methods.

In melt granulation, the granule particle size was well controlled by polyethylene glycol 6000 (PEG) content of which the optimum value was found to De 20%. Impeller speed and massing time in high shear mixer had small contribution to the particle growth when PEG content was optimized, while PEG particle size had some effect. Finer PEG powder improved the uniformity of granule size. Moreover, the cooling method of the hot mass affected the final granule properties significantly. The cooling with a fluid bed dryer was the best method.

Both of the retention rates of anethole and cinnamaldehyde in the final granule were more than 95% of initial doses irrespective of cooling method. Further, the adoption of a fluid bed dryer enabled very rapid cooling of hot granule with negligible loss of essential oils.