(201a) Transition From Batch to Continuous in Pharmaceutical Dry Ingredient Formulation

The Pharmaceutical formulation process has been based on batch weighing to achieve the correct weight of each component of the formulation.

Brabender Technologie is a manufacturer of dry ingredient feeders and its specialty is the continuous repeatable weigh feeding of dry ingredients into continuous processes. The principles in achieving repeatable continuous weighing are different from achieving batch weighing repeatability. There is a further complication, namely, the flow characteristics of dry ingredients resist ( fight against ) repeatable weigh feeding.

Achieving accurate weighing repeatability in continuous feeding of dry ingredients requires the ability to stabilize the negative flow characteristics of dry ingredients and accurately weigh a dynamic ( non static ) mass. Achieving this can have quality improvements and cost of production decreases to pharmaceutical formulation. But, the path to achieving continuous formulation has been a rocky road.

This presentation provides an understanding of the learning curve for development and production personnel, familiar with the batch based process, to understand the continuous weigh feeding process and develop a means to trust the integrity of the process. The steps in this learning curve include understanding the flow properties typical of some active ingredients, the principles of accurate feeding using single screw and twin screw feeders, the principles of continuos loss in weight feeding and continuous verification of the results on line.