EVALUATION OF THE MIXING EFFECTIVENESS OF A NEW POWDER MIXER

The effectiveness of the new powder mixer Canguro J tumbler was evalua ted using lactose, microcrystalline cellulose, and salicylic acid as c hemical indicator with the ratio 88:10:2 (w/w). The mixing time, the s peed of the tumbler (Ipm), its inclination, and filling percentage wer e varied in order to assess the limits of the mixer and the best param eters to use for obtaining a mixture as uniform as possible. The same experiments were then repeated after addition of 1% (w/w) magnesium st earate to the mixture of powders. The efficiency in the distribution o f this lubricant was estimated by the progressive hardness reduction o f the tablets derived from the compression of the powders, at a consta nt applied force. Finally, a comparison between Canguro J and a very e fficient V-shaped mixer of the same capacity was performed. The result s show that all investigated parameters influenced the mixing capabili ty of Canguro J. The best effectiveness of the mixer occurred at the f illing rate of 50% and a rotation speed of 20 Ipm; in this case, Cangu ro J is even a little more effective than the V-shaped miter. However, even at the filling rate of 70%, the same distribution uniformity of the powders can be obtained after a mixing time protraction of a few m inutes.