(273c) Effect of Particle Size and Density On Flow of Powder Through Feed Frames On Rotary Tablet Presses

Sinka, I. C., University of Leicester
Baserinia, R., University of Leicester
Woldu, A. B., Merck&Co., Inc.
Kheiripour, M., Merck&Co., Inc.
Rajniak, P., Merck Sharp and Dohme

Pharmaceutical tablets are manufactured using rotary tablet presses. In a typical press the powder formulation is placed in a hopper above the press which is connected through a vertical pipe to a feed frame which usually involves rotating paddles that transfer the powder horizontally over the die opening. The flow behaviour of the powder through the feed frame is critical to achieve high throughput of the press and maintain weight uniformity.

In this paper the flow of powders through a lab scale rotary feeder is examined. The system was presented elsewhere [1]. Five grades of microcrystalline cellulose are used to study the effect of particle size and particle density for the same base powder material. The flow rate of powders through the feeder is measured for different rotational speeds (25-250 rpm) and exit diameters of the feeder (5-20 mm). The flowability of the powders is discussed in relation to conventional powder flow measures (such as angle of repose and critical orifice diameter) as well as flow measures determined using a model shoe-die system for the same powders [2].


[1] Singh G., Givand J., Rajniak P., Chern R., Reynolds S.D.  and Sinka I.C. , 2012. Effect of paddle shape on flow of powder through feed frames on rotary tablet presses. Paper presented at: AIChE Annual Meeting, October 28 – November 2, Pittsburgh, PA.

[2] Mills L.A. and Sinka I.C., 2013. Effect of particle size and density on the die fill of powders. European Journal of Pharmaceutics and Biopharmaceutics. Accepted for publication.