July 28, 2021: Pharmaceutical Interview Questions and Answers

#BlendingAndMixing #BlendingAndMixingOperatingPrinciples #EquipmentClassificationsForBlendingAndMixing

1. What is Blending and Mixing?

Blending and Mixing is the process of reorientation of particles relative to one another in order to achieve uniformity.

2. What are the Operating Principles of different equipment for Blending and Mixing?

Types of Equipment	Operating Principles
Diffusion Blending (Tumble blending)	Particles are reoriented in relation to one another when they are placed in random motion and interparticular friction is reduced as the result of bed expansion (usually within a rotating container).
Convection Mixing (also known as paddle or plow mixing)	Particles are reoriented in relation to one another as a result of mechanical movement.
Pneumatic Mixing	Particles are reoriented in relation to one another as a result of the expansion of a powder bed by gas.

3. Equipment Classifications used for Blending and Mixing

Equipment type	Sub classification description	Sub classification
Diffusion Mixers (Tumble)	Diffusion mixer subclasses primarily are distinguished by geometric shape and the positioning of the axis of rotation.	• V-blenders • Double Cone Blenders • Slant Cone Blenders • Cube Blenders • Bin Blenders • Horizontal/ Vertical/ Drum Blenders • Static Continuous Blenders • Dynamic Continuous Blenders
Convection Mixers	Convection blender subclasses primarily are distinguished by vessel shape and impeller geometry.	• Ribbon Blenders • Orbiting Screw Blenders • Planetary Blenders • Forberg Blenders • Horizontal Double Arm Blenders • Horizontal High Intensity Mixers • Vertical High Intensity Mixers • Diffusion Mixers (Tumble) with Intensifier/Agitator
Pneumatic Mixers	Although pneumatic mixers may differ from one another in vessel geometry, air nozzle type, and air nozzle configuration, no pneumatic mixer subclasses have been identified.	No sub lass

Source: fda.gov