Oral and topical suspensions

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