Study Set Content:
A typical problem for disintegrating products
Especially if hydrophobic
Cone Formation
Fluid interchange only at surface
Center of cone may be
saturated solution
may overcome problem OF CONE FORMATION
Increasing rotation speed
A small, loose piece of nonreactive material, such as not more than a few turns of wire helix, may be attached to dosage units that would otherwise float.
Sinkers
Alternative sinker devices
Sinkers
USP Apparatus 3 – Reciprocating Cylinder
Advantages:
-Programmable to run dissolution in different media and at
different speeds at various times
Attempt to stimulate pH changes in the GI tract e.g
pH 1, pH 4.5, pH 6.8
Disadvantages:
-
Not suitable for dosage forms that disintegrate into
small particles
Surfactants cause
foaming
Small vessel
volume
Media evaporation for tests of
long duration
USP Apparatus 4 – Flow through Cell
Volume of media
not limited
Suitable for
poorly soluble drugs
Gentle hydrodynamic
conditions
Disadvantages:
_____ with use of the apparatus – no USP monographs
Limited experience
influences the results
Pump precision
Specifications
•
Media temp:
37 +/- 0.5 C
is the preferred medium. With no enzymes incorporated.
Distilled water
Sample size: 6 units- _____, Retest _____, Retest _____
initial, 1 +6, 2 +12
Common Operating Speeds: _____ rpm for Basket, 50 rpm for paddle type.
100,50
