Development of a micro-dosing system for fine powder using a vibrating capillary. Part 2. The implementation of a process analytical technology tool in a closed-loop dosing system.

In an earlier study, a micro-dosing system for fine powder using a vibrating capillary which can precisely dose various lactose powders, was introduced. In scaling up to a multi-track dosing system, it was suggested that additional track cut-offs can improve the dosing performance by reducing the overruns. A non-contact in-line control unit within a closed-loop system is required to achieve this goal. Due to its very fast response time (a few milliseconds) a capacitive sensor was integrated together with multi track cut-offs into a closed-loop dosing system. With this improvement a standard dosing deviation as low as 0.1mg was achieved. The results suggest its application in precise filling of fine pharmaceutical powders.