In general the dissolution medium volume should be 3-10
times the saturation solubulity of the drug. Sink
conditions means thd drug which goes in to the solution is
not effected by the drug which not dissolved.
One of the requirements to conduct an appropriate drug
dissolution test is to use a sufficient volume of
dissolution medium, which should be able to dissolve the
expected amount of drug released from a product. This
ability of the medium to dissolve the expected amount of
drug is known as a “sink condition”.It is important to note
that a dissolution test should not be conducted in a volume
of the medium which would not dissolve the expected amount
of the drug completely and freely.