M1L9 - Powder mixing

Random mixing

This is achieved when the average of each particle type is close to the ideal mean, and variability is a small % of the mean

Diffusive mixing

This occurs when individual particles change position relative to neighbouring particles randomly

Convective mixing

This occurs when groups transfer between adjacent locations

Shear mixing

This occurs when particles are forced past each other by the mixing procedure, by contact with the blade/paddle/spatula

Segregation

This occurs when particles in a mixture separate, affected by particle size, shape, density, effect from gravity, and symmetrical movement

Percolation

This refers to small particles moving between voids of large particles

Trajectory

This refers to larger particles travelling further when impacted by the mixing procedure

Densification

This refers to the caking of fine particles after percolation

Dusting segregation

This occurs when fine powders become airborne during mixing, then settle on the top of the mixture

Interactive mixture

This is created when particles adhere to the surface of carrier particles in a controlled manner

Geometric dilution

This refers to a mixing process wherein a small amount of drug is added to a bulk, and slowly added, doubling amounts to prevent hotspots and ensure proper distribution

Thief probe sampling

This uses a multi-tube probe to collect samples from deep within containers