Improvements in the manufacturing of pharmaceutical dry powder formulations: a novel method of blend analysis using a coloured tracer

The optimisation of dry powder pharmaceutical blending is very challenging, and often relies on costly and time consuming trial-and-error approaches which waste a lot of material. A novel method has been developed which can be used in place of the drug to quickly and effectively evaluate the progression of a dry powder mixing. By blending a small amount of colour tracer with the pharmaceutical formulation bulk, a vast amount of information on blend kinetics and behaviour can be extracted. Information on the degree of tracer spread and breakup can be obtained from measurement of the blend’s colour, as well as providing quantitative insight into the energy input to the blend and its uniformity. It can also be used to identify conditions which may cause unintentional and undesirable particle damage during blending. By reducing the amount of drug required in preliminary testing, the colour tracer method provides a cost effective means of ensuring equivalent blending conditions between mixer types, scales and operating conditions.