Solids 5

Spatulation

blending small amounts of powders by movement of a spatula through them on a sheet of paper or an ointment tile

Grinding/trituration

mixing powders with a mortar and pestle

Sifting

mixing powders by passing them through sifters resulting in a light, fluffy product

Tumbling

mixing powders in a rotating V chamber

Ribbon mixers

spiral ribbons are mounted on a shaft, located in the center of the mixing equipment. rotating of the ribbons mixes the powder

What blending methods are most suitable for small-scale mixing?

spatulation, grinding/trituration, sifting

Which methods are not suitable for powders with poor flowability?

sifting, tumbling

Which methods best avoid segregation of the mixture?

ribbon mixer, tumbling

Which methods are not acceptable for the incorporation of potent drugs into a diluent powder?

spatulation, sifting

Eutectic mixture

a homogenous solid mix of two or more chemical species that when mixed becomes sticky or may liquefy because of decreased melting point

Explosive mixture

reacts violently when mixed; special precautions must be taken