5.3.1 Oral and topical suspensions
The following groups of products can be offered for stabilizing oral and topi-
cal suspensions.
A. Soluble Kollidon products Low concentrations, i.e. 2 – 5 , of
Kollidon 90 F suffice to stabilize aqueous suspensions. Fig. 4
demonstrates that it can comple- tely prevent sedimentation. The
example taken was a crospovidone suspension.
A combination consisting of 2 of Kollidon 90 F and 5 – 9 of Kollidon
CL-M has proved to be an effective system for stabilizing suspensions.
Kollidon 30 is also used for this pur- pose. It can be combined with all
conventional suspension stabilizers thickeners, surfactants, etc..
B. Kollidon CL-M The use of Kollidon CL-M as a sus-
pension stabilizer has nothing whatever to do with the principle of
increasing the viscosity. The addi- tion of 5 – 9 has practically no ef-
fect in changing the viscosity, but strongly reduces the rate of sedi-
mentation and facilitates the redis- persability, in particular, an effect
that is consistent with the low vis- cosity. One of the reasons for this
Kollidon CL-M effect is its low bulk density, which is only half of that of
conventional crospovidone, e.g. Kollidon CL. It can clearly be seen
from Fig. 5 that a relative volume of sediment of normal micronized
crospovidone of high bulk density = Crospovidone M is less and
more compact that of Kollidon CL-M, which undergoes hardly any
sedimentation.
In this book, a number of formulations for made-up suspensions or extem-
poraneous suspensions produced from instant granules or dry syrups
BASF Fine Chemicals Generic Drug Formulations 1998
100
50
without Povidone with 5 Kollidon 90 F
R e
la ti
v e
s e
d im
e n
t v
o lu
m e
2 4
h ,
Fig. 4 Effect of Kollidon 90 F on the volume of sediment in a crospovidone suspension 7.5 in water
see Chapter 4 illustrate the use of Kollidon CL-M.
C Lutrol F products The polyoxamers, Lutrol F 68 and
Lutrol F 12 7, in concentrations of 2 – 5 , expressed in terms of the
final weight of the suspension, of- fer a further opportunity of stabiliz-
ing suspensions. They also do not increase the viscosity when used in
these amounts and can be com- bined with all other conventional
suspension stabilizers.
5.3.2 Parenteral suspensions