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Title: Powder die filling under gravity and suction fill mechanisms
Authors: Baserinia, R
Sinka, IC
First Published: 10-Feb-2019
Publisher: Elsevier
Citation: Int J Pharm, 2019, in press
Abstract: In pharmaceutical tablet manufacturing, the powder formulation is filled into a die and compacted into a tablet using rigid punches. Die fill is important because it limits the productivity of tablet presses and determines key quality attributes of tablets including weight and content uniformity. Die fill occurs due to gravity and suction fill mechanisms. A model linear shoe-die filling system has been instrumented with pressure measurement devices for detailed characterisation of air pressure evolution as the powder mass is delivered in the die. Systematic experiments were carried out using a range of microcrystalline cellulose powders to explore the role of powder properties (such as particle size and bulk density) and operating parameters (such as shoe and die geometry, shoe and suction punch kinematics and powder filling level) on powder delivery. Existing models were found inadequate to describe the mass flow rate of powders under a diversity of gravity and suction filling conditions. The pressure measurements enabled the development of a new die fill model using the Buckingham Π theorem. The model includes separate terms for the contribution of the mass of powder delivered under gravity and suction fill mechanisms. The experimental procedures required to extract model parameters are described. The model is applicable to the handling and dosing of fine and cohesive powders where small differences in air pressure have a significant impact on the powder flow process. The practical application of the model for predicting die filling behaviour in a high-speed rotary tablet press is demonstrated by assuming operating conditions of a typical rotary tablet press. This approach can be adapted to assist formulation design and process development for operations involving handling and dosing of fine and cohesive powder.
DOI Link: 10.1016/j.ijpharm.2019.01.068
eISSN: 1873-3476
Embargo on file until: 10-Feb-2020
Version: Post-print
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2019 Elsevier B.V. After an embargo period this version of the paper will be an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License (, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Description: The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.
Appears in Collections:Published Articles, Dept. of Engineering

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