Oral formulations: crystals preformulation & powders 1

Question 1

What are the 4 fundamentals of powder flow?

Answer 1

gravity 
surface forces (surface area & surface energy) 
geometric factors (size, size distribution, shape, texture)
physical factors (solid bridges between particles, binder,crystallisation

Question 2

What are the four different flow types?

Answer 2

Mass flow, cone flow, arching, rat-holing

Question 3

Which is better for flow large or small article size?

Answer 3

large

Question 4

What is angle of repose? is a high a good flow or poor flow?

Answer 4

angle of free surface of a pile of powder with respect to horizontal plane
high a - poor flow
low a - good flow

Question 5

what is tan a?

Answer 5

co efficient of friction

Question 6

What is critical orifice diameter?

Answer 6

smallest hole through with powder flows

small values good

Question 7

What is the carr’s index equation?

Answer 7

= (tapped density - fluff density)/ tapped density x 100

Question 8

How can you increase flow?

Answer 8

bigger particle less cohesive 
sieve small particle 
granulate
spray drying - spherical particles
reduce electrostatic forces 
reduce moisture

Question 9

What do glidants do and name some examples?

Answer 9

reduce cohesion - talc, maize starch, colloidal silicone dioxide

Question 10

what do lubricants do? name some examples

Answer 10

reduce adhesion - talc, magnesium stearate, poly(ethylene) glycol (PEG)

Question 11

why are crystals good?

Answer 11

pure
simple characterisation
stable

Question 12

How is a stable and meta-stable system defined?

Answer 12

stable- lowest free energy state, cannot spontaneously change - graphite
meta - not quite lowest free energy state can spontaneously change - diamond