Properties of microcrystalline cellulose and powder cellulose after extrusion/spheronization as studied by fourier transform Raman spectroscopy and environmental scanning electron microscopy

Abstract

In this study, the effect of powder cellulose (PC) and 2 types of microcrystalline cellulose (MCC 101 and MCC 301) on pellet properties produced by an extrusion/spheronization process was investigated. The different investigated types of cellulose displayed different behavior during the extrusion/spheronization process. Pure PC was unsuitable for extrusion, because too much water was required and the added water was partly squeezed during the extrusion process. In contrast, MCC 101 and MCC 301 were extrudable at a wide range of water content, but the quality of the resulting products varied. In the extrusion/spheronization process, MCC 101 was the best substance, with easy handling and acceptable product properties. The properties of the extrudates and pellets were determined by Fourier transform (FT) Raman spectroscopy and environmental scanning electron microscopy (ESEM). FT-Raman spectroscopy was able to distinguish between the original substances and also between the wet and dried extrudates. The particle sizes of the raw material and of the extrudates were determined by ESEM without additional preparation. For MCC, the size of the resulting particles within the extrudate or pellet was smaller. However, in the extrudates of PC, changes in particle size could not be observed.

Small-scale twin-screw extrusion – evaluation of continuous split feeding

“…The wet extrusion process cannot perform in a discontinuous operating extruder with conical screws as described before. A phase separation between powder and liquid would occur due to hydrostatic pressure [35]. The wet extrusion process can also be challenging when using larger equipment because of feeding issues [5].…”

“…A phase separation between powder and liquid would occur due to hydrostatic pressure. [35] The wet extrusion process can also be challenging when using larger equipment because of feeding issues. [5] The 20-g material required in this study was determined by the minimum load of the spheronizer.…”

Using Raman spectroscopy in tablet moisture surface analysis: Tablet surface markers

“…We studied the 1095 cm −1 and 1292 cm −1 the two major peaks in the Raman spectrum of microcrystalline cellulose [25].…”

Process analytical applications of Raman spectroscopy

“…They reported the detection of both recrystallization of the amorphous component and dehydration after the tableting process. Fechner et al (2003) utilized Raman spectroscopy in the extrusion-spheronization process environment and they explained the effect of water on the structure of cellulose during this unit operation. Wet granulation is followed by drying, in which the product is thermally stressed.…”