Quantitative Evaluation of Kneading and Extrusion Processes by Pressure Transmission Characteristics of Wet Kneaded Mass.

Okamoto

Tsuhari

et al. 2002

Self Cite

Kneading of powder materials [1][2][3] has been well used in the pharmaceutical, agriculture, food, chemical, forage and fertilizer industries. Most of the cases, kneading operation is conducted just before the extrusion or molding processes, and the performance of kneading seriously affects quality of the final product or process efficiency. Therefore, it is important to quantitatively analyze and monitor the kneading process.So far, a high shear mixer has been well used for wet granulation 4) as well as for wet kneading. In the case that the high shear mixer is used for wet kneading, several advantageous points such as easy to disassemble with easy cleaning can be pointed out. However, the problems such as enormous sticking on the vessel wall or larger physical strength of extruded pellets that may cause longer dissolution time have also been known on the contrary. It is required to improve the problems of high shear mixer while keeping the advantageous points when applied to wet kneading.In this study, a multi-functional vertical high shear kneader has been newly developed and applied for wet kneading. Wet kneading of pharmaceutical powders composed of acetaminophen and excipients was conducted under various blade components and operating conditions. Dispersion of aqueous binder and compression properties of wet mass was investigated to quantitatively analyze the kneading condition. Dried pellets were then produced through a dome type extrusion granulator and a fluidized bed drier, and physical properties of the pellets were examined experimentally.Comparison between kneading performance of the novel kneader and of a conventional high shear mixer (granulator) was also conducted. ExperimentalApparatus Figure 1 shows a schematic diagram of multi-functional vertical high shear kneader (SPG-10, Fuji Paudal Co., Ltd.) developed. The vessel is a laboratory size, which has an inner diameter of 290 mm and a capacity of 10 l. The bottom of the vessel is equipped with a kneading blade that rotates horizontally. Several operating parameters such as torque of main shaft, power consumption of motor drive and temperature of kneaded mass can be continuously measured and monitored via a personal computer. Chopper blade can also be installed onto the sidewall of the vessel, if necessary. Figure 2 illustrates a newly developed kneading blade, and Fig. 3 shows appearance of various blades used. The kneading blade is composed of four parts; (a) scraper, (b) main blade, (c) dispersion blade, and (d) cap. The main blade has an edge having inclination of 20 degrees to the backward, opposite direction of the blade movement. This is designed so as to press down the wet kneaded mass, and to add high compaction force and high shear stress to the mass (typically, main agitator blade of high shear mixer (granulator) has an edge to the opposite direction of our kneading blade, thus powders are lifted up by the edge inclination). The dispersion blade equipped on the top of the main blade works to move away the wet mass to the vessel outsid...

show abstract

Section: Resultsmentioning

confidence: 77%

mentioning

confidence: 99%

Development of a Novel Vertical High Shear Kneader and Its Performance in Wet Kneading of Pharmaceutical Powders.

Okamoto

Tsuhari

et al. 2002

Self Cite

show abstract

“…For extrusion granulation after the kneading, a dome-type extruder [2][3][4] (DG-L1, Fuji Paudal Co. Ltd.) was used. This extruder consists of a hemispherical dome type punching screen (diameter of the dome is 58 mm, diameter of each hole and width of the screen are both 0.8 mm, and the opening area ratio is 22.5%), single shaft, screws and extrusion blade at the extremity of the shaft.…”

Section: Methodsmentioning

confidence: 99%

“…1) We have shown that the newly developed kneader was very effective to uniformly disperse water in wet kneading with minimizing the adhesion onto vessel wall 1) and the wet kneading conditions seriously determined the physical properties of dry pellets prepared by extruding the wet kneaded mass and fluidized bed drying. [2][3][4][5] However, mechanism of kneading and its scale-up characteristics have not been studied yet.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Scale-Up of Wet Kneading in a Novel Vertical High Shear Kneader

Okamoto

Sato

et al. 2005

Self Cite

Quantitative Analysis of Water Dispersion Conditions and Pressure Transmission Characteristics of a Wet Kneaded Mass.

Furukawa

Osako

et al. 2001

Self Cite