Mechanism of the formation of hollow spherical granules using a high shear granulator

Publication date: 30 May 2018
Source:European Journal of Pharmaceutical Sciences, Volume 117
Author(s): Takumi Asada, Mitsunori Nishikawa, Yasushi Ochiai, Shuji Noguchi, Shin-ichiro Kimura, Yasunori Iwao, Shigeru Itai
Recently, we have developed a novel granulation technology to manufacture hollow spherical granules (HSGs) for controlled-release formulations; however, the mechanism of the granulation is still unclear. The aim of this study is to determine the mechanism of the formation of the HSGs using a high shear granulator. Samples of granulated material were collected at various times during granulation and were investigated using scanning electron microscope and X-ray computed tomography. It was observed that the granulation proceeded by drug layering to the polymer, followed by formation of a hollow in the granule. In addition, it was also found that generation of a crack in the adhered drug layer and air flow into the granules might be involved in forming the hollow in the structure. Observation of the granulation of formulations with different types of drugs and polymers indicated that negative pressure in the granules occurred and the granules caved in when the hollow was formed. The hollow-forming speed and the shell density of the hollow granules depended on the particular drug and polymer. Taken together, the granulation mechanism of HSGs was determined and this information will be valuable for HSGs technology development.

Graphical abstract

http://ift.tt/2IIirok