Changes in material properties accompanying the national formulary (NF) identity test for microcrystalline cellulose.

It has been found that the current NF identity test for microcrystalline cellulose is actually an assay of the response of the material to energy dissipation expended during the analysis procedure. The blending step needed to effect suspension of the material results in a disintegration of the microcrystalline particles and a concomitant increase in the viscosity of the slurry viscosity. These effects were shown not to be unique functions of either blender speed or blending time. The passage or failure of a given sample of microcrystalline cellulose under the conditions of the identity test was found to be a consequence of the test conditions used. Any given sample of microcrystalline cellulose can be made to pass the identity test if it is blended for a sufficiently long time or at a sufficiently high speed. The test is sufficient, however, to differentiate powdered cellulose from powdered cellulose.